Magnetic sensor

A first conductor includes a first base section and a first narrow section. The area of the exterior surface of the first narrow section as viewed from a direction perpendicular or substantially perpendicular to an insulating layer is smaller than that of the first base section. The first base section and the first narrow section are provided side by side in the direction perpendicular or substantially perpendicular to the insulating layer. A stress relaxer including a material different from that of the first conductor is provided in a region which is surrounded by the exterior surface of the first narrow section and also by the exterior surface of the first base section, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetic sensor, and more particularly, to a magnetic sensor including magnetoresistance elements.

2. Description of the Related Art

Examples of the related art that disclose a magnetic sensor are Japanese Unexamined Patent Application Publication No. 2013-44641, International Publication No. 2015/182365, International Publication No. 2016/013345, International Publication No. 2007/119569, and Japanese Unexamined Patent Application Publication No. 2017-166925.

The magnetic sensor disclosed in Japanese Unexamined Patent Application Publication No. 2013-44641 includes first through fourth magnetoresistance elements formed in a meandering shape and connected with each other to form a bridge circuit. The surfaces of the first through fourth magnetoresistance elements are covered with an insulating film. A magnetic-flux converging film including a magnetic material is formed on the surfaces of the third and fourth magnetoresistance elements, which are fixed resistors, with the insulating film provided therebetween.

The magnetic sensors disclosed in International Publication No. 2015/182365 and International Publication No. 2016/013345 each include first and second magnetoresistance elements. The rate of a change in the resistance of the second magnetoresistance element is smaller than that of the first magnetoresistance element. The first magnetoresistance element, which is a magneto-sensitive element, includes concentrically provided patterns.

The magnetic sensor disclosed in International Publication No. 2007/119569 includes a semiconductor substrate and a magnet. The semiconductor substrate includes multiple Hall elements. The magnet has a magnetism amplifying function provided on the semiconductor substrate. An underlying layer, which serves as a base of the magnet, is provided on the semiconductor substrate. The coefficient of thermal expansion of the underlying layer is different from that of the multiple Hall elements. The underlying layer is large enough to at least partially cover a region where the multiple Hall elements are provided. The area of the magnet is larger than that of the underlying layer.

The magnetic sensor disclosed in Japanese Unexamined Patent Application Publication No. 2017-166925 includes a semiconductor substrate and a magnet. The semiconductor substrate includes multiple Hall elements. The magnet has a magnetic-flux converging function provided on the semiconductor substrate. An outer peripheral section of the magnet on the semiconductor substrate defines the exterior surface of the magnet in a longitudinal section. The outer peripheral section at least partially includes a curved portion and a portion substantially parallel with the semiconductor substrate. At least a portion of a structure including a non-magnetic material is embedded in the magnet.

In the magnetic sensor disclosed in Japanese Unexamined Patent Application Publication No. 2013-44641, each of the first and second magnetoresistance elements, which are magneto-sensitive elements, includes a meandering pattern. This decreases the isotropic characteristics in detecting a horizontal magnetic field.

In each of the magnetic sensors disclosed in International Publication No. 2015/182365 and International Publication No. 2016/013345, the first magnetoresistance element includes concentrically provided patterns. Because of this configuration, the magnetic sensors exhibit high isotropic characteristics in detecting a horizontal magnetic field. However, they are unable to detect a weak vertical magnetic field.

The magnetic sensors disclosed in International Publication No. 2007/119569 and Japanese Unexamined Patent Application Publication No. 2017-166925 are magnetic sensors including Hall elements, and are not intended to detect a horizontal magnetic field and a vertical magnetic field by using magnetoresistance elements.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide magnetic sensors each of which provide high isotropic characteristics in detecting a horizontal magnetic field and are also able to detect a weak vertical magnetic field by using magnetoresistance elements and also to regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements.

A magnetic sensor according to a preferred embodiment of the present invention includes a magneto-sensitive element, an insulating layer, a first conductor, a first magnet, and a member. The insulating layer covers the magneto-sensitive element. The first conductor is provided on the insulating layer. The first magnet is provided on the first conductor and covers the first conductor, as viewed from a direction perpendicular or substantially perpendicular to the insulating layer. The member is provided along a portion of the first conductor and includes a material different from that of the first conductor. The first conductor includes a first base section and a first narrow section. The area of the exterior surface of the first narrow section as viewed from the direction perpendicular or substantially perpendicular to the insulating layer is smaller than that of the first base section. The first base section and the first narrow section are provided side by side in the direction perpendicular or substantially perpendicular to the insulating layer. The member, which includes a material different from that of the first conductor, is provided in a region which is surrounded by the exterior surface of the first narrow section and also by the exterior surface of the first base section, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, in the direction perpendicular or substantially perpendicular to the insulating layer, the first narrow section of the first conductor is provided at an end portion of the first conductor closer to the insulating layer. The member, which includes a material different from that of the first conductor, is provided between the first base section and the insulating layer.

In a preferred embodiment of the present invention, in the direction perpendicular or substantially perpendicular to the insulating layer, the first narrow section of the first conductor is provided at an end portion of the first conductor closer to the first magnet. The member, which includes a material different from that of the first conductor, is provided between the first base section and the first magnet.

In a preferred embodiment of the present invention, in the direction perpendicular or substantially perpendicular to the insulating layer, the first base section of the first conductor is provided at an end portion of the first conductor closer to the insulating layer and is also provided at an end portion of the first conductor closer to the first magnet. In the direction perpendicular or substantially perpendicular to the insulating layer, the first narrow section of the first conductor is sandwiched between the first base sections of the first conductor. The member, which includes a material different from that of the first conductor, is sandwiched between the first base sections.

In a preferred embodiment of the present invention, the member, which includes a material different from that of the first conductor, is a stress relaxer.

In a preferred embodiment of the present invention, a first magnetoresistance element is provided as the magneto-sensitive element. The magnetic sensor further includes a second magnetoresistance element that is electrically connected to the first magnetoresistance element to define a bridge circuit. The second magnetoresistance element is covered by the insulating layer.

In a preferred embodiment of the present invention, the magneto-sensitive element has an outer peripheral edge. The first magnet is provided in a region farther inward than the outer peripheral edge of the magneto-sensitive element, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the first magnetoresistance element also has an inner peripheral edge. The second magnetoresistance element is provided in a region farther inward than the inner peripheral edge of the first magnetoresistance element and is covered by the first magnet, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the magnetic sensor further includes a second conductor and a second magnet. The second conductor is provided on the insulating layer and is different from the first conductor, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer. The second magnet is provided on the second conductor and covers the second conductor, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer. The second magnet is different from the first magnet. The second magnetoresistance element is provided in a region farther outward than the outer peripheral edge of the first magnetoresistance element and is covered by the second magnet.

In a preferred embodiment of the present invention, the second conductor includes a second base section and a second narrow section. The area of the exterior surface of the second narrow section as viewed from the direction perpendicular or substantially perpendicular to the insulating layer is smaller than that of the second base section. In the second conductor, the second base section and the second narrow section are provided side by side in the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, in the direction perpendicular or substantially perpendicular to the insulating layer, the second narrow section of the second conductor is provided at an end portion of the second conductor closer to the insulating layer.

In a preferred embodiment of the present invention, in the direction perpendicular or substantially perpendicular to the insulating layer, the second narrow section of the second conductor is provided at an end portion of the second conductor closer to the second magnet.

In a preferred embodiment of the present invention, in the direction perpendicular or substantially perpendicular to the insulating layer, the second base section of the second conductor is provided at an end portion of the second conductor closer to the insulating layer and is also provided at an end portion of the second conductor closer to the second magnet. In the direction perpendicular or substantially perpendicular to the insulating layer, the second narrow section of the second conductor is sandwiched between the second base sections of the second conductor.

A magnetic sensor according to a preferred embodiment of the present invention includes a magneto-sensitive element, an insulating layer, a first magnet, and a stress relaxer. The insulating layer covers the magneto-sensitive element. The first magnet is provided on the insulating layer. The stress relaxer is provided along a portion of the first magnet and includes a material different from that of the first magnet. The magneto-sensitive element has an outer peripheral edge. The first magnet is provided in a region farther inward than the outer peripheral edge of the magneto-sensitive element, as viewed from a direction perpendicular or substantially perpendicular to the insulating layer. The first magnet includes a first base section and a first narrow section. The area of the exterior surface of the first narrow section as viewed from the direction perpendicular or substantially perpendicular to the insulating layer is smaller than that of the first base section. In the first magnet, the first base section and the first narrow section are provided side by side in the direction perpendicular or substantially perpendicular to the insulating layer. In the direction perpendicular or substantially perpendicular to the insulating layer, the first narrow section of the first magnet is provided at an end portion of the first magnet closer to the insulating layer. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer, the stress relaxer is provided in a region which is surrounded by the exterior surface of the first narrow section and also by the exterior surface of the first base section, and is provided between the first base section and the insulating layer.

In a preferred embodiment of the present invention, a first magnetoresistance element is provided as the magneto-sensitive element. The magnetic sensor further includes a second magnetoresistance element. The second magnetoresistance element is electrically connected to the first magnetoresistance element to define a bridge circuit. The second magnetoresistance element is covered by the insulating layer.

In a preferred embodiment of the present invention, the first magnetoresistance element also has an inner peripheral edge. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer, the second magnetoresistance element is provided in a region farther inward than the inner peripheral edge of the first magnetoresistance element and is covered by the first magnet.

In a preferred embodiment of the present invention, the magnetic sensor further includes a second magnet. The second magnet is provided on the insulating layer and is different from the first magnet. The second magnetoresistance element is provided in a region farther outward than the outer peripheral edge of the first magnetoresistance element and is covered by the second magnet.

In a preferred embodiment of the present invention, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer, at least a portion of the first magnetoresistance element is located in at least a portion of the area from a position separated inward from the outer peripheral edge of the first magnet by about 2 μm to a position separated outward from the outer peripheral edge of the first magnet by y μm defined by the following expression (I):
y=−0.0008x2+0.2495x+6.6506  (I)

where the thickness of the first magnetoresistance element is x μm.

In a preferred embodiment of the present invention, the first magnet is provided concentrically with the outer peripheral edge of the first magnetoresistance element, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the second magnetoresistance element is provided in a region farther inward than the inner peripheral edge of the first magnetoresistance element and is covered by the first magnet, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer. The first magnet is provided in a region including the inner peripheral edge of the first magnetoresistance element and the area inward of the inner peripheral edge, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the second magnetoresistance element is provided in a region farther inward than the inner peripheral edge of the first magnetoresistance element and is covered by the first magnet, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer. The first magnet does not cover the first magnetoresistance element, but covers the second magnetoresistance element, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the second magnetoresistance element is located in the area from the center of the first magnet to the position separated inward from the outer peripheral edge of the first magnet by about 7 μm, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the second magnetoresistance element is provided in a region farther outward than the outer peripheral edge of the first magnetoresistance element and is covered by the second magnet, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer. The first magnet covers only a portion of the first magnetoresistance element among the first and the second magnetoresistance elements, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the second magnet does not cover the first magnetoresistance element, but covers the second magnetoresistance element, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the second magnetoresistance element is located in the area from the center of the second magnet to the position separated inward from the outer peripheral edge of the second magnet by about 7 μm, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

In a preferred embodiment of the present invention, the first magnetoresistance element includes multiple first patterns that are concentrically provided and are connected with each other, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer.

According to preferred embodiments of the present invention, high isotropic characteristics in detecting a horizontal magnetic field are able to be provided, a weak vertical magnetic field is able to be detected by magnetoresistance elements, and also a decrease in the output accuracy of a magnetic sensor, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements, is able to be regulated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Magnetic sensors according to preferred embodiments of the present invention will be described below with reference to the drawings. In the following description of the preferred embodiments, the same element or associated elements shown in the drawings are designated by like reference numeral, and an explanation thereof will not be repeated.

First Preferred Embodiment

FIG. 1is a perspective view showing a magnetic sensor according to a first preferred embodiment of the present invention.FIG. 2is a sectional view of the magnetic sensor inFIG. 1, as viewed from the direction indicated by the arrow of line II-II inFIG. 1.FIG. 3is a sectional view of the magnetic sensor inFIG. 2, as viewed from the direction indicated by the arrow of line III-III inFIG. 2.FIG. 4is a plan view of the magnetic sensor inFIG. 1, as viewed from the direction indicated by the arrow IV inFIG. 1.FIG. 5is an equivalent circuit diagram of the magnetic sensor according to the first preferred embodiment of the present invention.

InFIG. 1, the widthwise direction of a circuit substrate100, which will be discussed later, is the X-axis direction, the longitudinal direction thereof is the Y-axis direction, and the thickness direction thereof is the Z-axis direction. InFIG. 4, the outer edges of first magnets, which will be discussed later, are indicated by dotted lines. InFIG. 4, some elements, for example, a differential amplifier and a temperature compensation circuit, which will be discussed later, are not shown.

As shown inFIGS. 1 through 4, a magnetic sensor1according to the first preferred embodiment of the present invention includes the circuit substrate100and two first magnets40provided above the circuit substrate100. In the magnetic sensor1according to the first preferred embodiment of the present invention, two first conductors60are provided on the circuit substrate100. A first stress relaxer80is provided along a portion of each of the first conductors60. An insulating layer30is provided on the front layer of the circuit substrate100, and the two first conductors60and the first stress relaxers80are located on the insulating layer30, as will be described. The circuit substrate100includes a semiconductor substrate110.

Each of the first conductors60includes a first base section61and a first narrow section62. The area of the exterior surface of the first narrow section62as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30, is smaller than that of the first base section61. In the first conductor60, the first base section61and the first narrow section62are provided side by side in the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30. In the present preferred embodiment, the first narrow section62of the first conductor60is located at the end portion of the first conductor60closer to the insulating layer30in the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30. That is, the first narrow section62of the first conductor60contacts the insulating layer30on the circuit substrate100.

As viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30, the exterior surface of each of the first base section61and the first narrow section62is circular or substantially circular, for example. The diameter of the exterior surface of the first narrow section62is smaller than that of the first base section61. The first base section61and the first narrow section62are provided substantially coaxially. The first base section61is not restricted to the above-described shape and may have an elliptical or polygonal shape, for example, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The first narrow section62is not restricted to the above-described shape and may have any shape if the area of the exterior surface as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30, is smaller than that of the first base section61.

The first narrow section62in the first conductor60defines a gap partially between the first base section61and the insulating layer30. In the first preferred embodiment, the gap is provided between the first base section61and the insulating layer30all around the outer peripheral portion of the first conductor60. The first stress relaxer80is provided in this gap.

The two first magnets40are located on the two first conductors60in a one-on-one relationship. The first magnets40cover the associated first conductors60, as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30.

With a view to decreasing the distance between each first magnet40and the circuit substrate100, the thickness of the first conductor60in the Z-axis direction, that is, the total thickness of the first base section61and the first narrow section62in the Z-axis direction, is preferably about 2.0 μm or smaller, for example. As the distance between the first magnet40and the circuit substrate100is smaller, the magnetic shielding function of the first magnet40, which will be discussed later, is able to be provided more effectively. To form the first conductor60, patterning with a resist, for example, may be utilized.

In the first preferred embodiment, the first conductor is positioned on the insulating layer30and is preferably defined by, for example, a layer including titanium (Ti) and a layer including gold (Au) in this order from the bottom. The layer including titanium (Ti) is a contact layer. If the first magnet40is formed with electrolytic plating, the layer including gold (Au) defines and functions as an electrode reaction layer, that is, a seed layer. The first conductor60is not limited to the above-described features, and may include a layer including, for example, at least one of iron (Fe), molybdenum (Mo), tantalum (Ta), platinum (Pt), and copper (Cu), which are materials defining and functioning as a plating seed layer. If the first magnet40is formed by a method other than plating, for example, by vapor-deposition, the first conductor60may be defined by a conductor including at least one of a metal or a resin, for example.

Each of the first stress relaxers80is provided in a region T1which is surrounded by the exterior surface of the first narrow section62and also by the exterior surface of the first base section61, as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30. In the first preferred embodiment, the first stress relaxer80is sandwiched between the first base section61and the insulating layer30. The first stress relaxer80is located immediately under the outer peripheral portion of the first base section61. As viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30, the first stress relaxer80has a ring shape. The first stress relaxer80is not limited to this shape and may have an elliptical ring shape or a polygonal ring shape in horizontal cross section. To form the first stress relaxer80, patterning with a resist, for example, may be utilized.

The first stress relaxer80is made of a material different from that of the first conductor60. As the material of the first stress relaxer80, at least one of, for example, a material having a lower adhesiveness, a material having a lower elastic modulus, and a material having a lower tensile strength than the material of the first conductor60is able to be used. The adhesiveness is the adhesiveness of the first stress relaxer80with an adjacent component or element. In the first preferred embodiment, the adhesiveness is that of the first stress relaxer80with the insulating layer30.

If the first stress relaxer80includes a material having a low adhesiveness, a layer including a low-adhesiveness material is provided in contact with the insulating layer30. The material of the first stress relaxer80having a lower adhesiveness than that of the first conductor60is preferably, for example, gold (Au) or polyimide. For example, the first conductor60may be defined by a layer including titanium (Ti) on the insulating layer30and a layer including gold (Au) on the layer including titanium (Ti). The first stress relaxer80is defined only by a layer including gold (Au).

The material of the first stress relaxer80having an elastic modulus lower than that of the first conductor60is preferably a resin, for example, polyimide. The material of the first stress relaxer80having a tensile strength lower than that of the first conductor60is preferably SiO2or a low-density resin, for example. To form the first stress relaxer80including SiO2, SOG (Spin-on Glass) may be applied onto the insulating layer30.

As shown inFIGS. 4 and 5, four magnetoresistance elements electrically connected with each other by wiring to define a Wheatstone bridge circuit are provided on the circuit substrate100of the magnetic sensor1according to the first preferred embodiment of the present invention. The four magnetoresistance elements are defined by two pairs of first magnetoresistance elements and second magnetoresistance elements. More specifically, the magnetic sensor1includes first and second magnetoresistance elements120aand130aand first and second magnetoresistance elements120band130b. The first and second magnetoresistance elements120aand130adefine one pair. The first and second magnetoresistance elements120band130bdefine the other pair.

In the first preferred embodiment, the magnetic sensor preferably includes two pairs of first and second magnetoresistance elements. However, this is only an example. It is sufficient if the magnetic sensor1includes at least one pair of first and second magnetoresistance elements. If the magnetic sensor1includes one pair of first and second magnetoresistance elements, a half bridge circuit is provided on the circuit substrate100.

Each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bis preferably an AMR (Anisotropic Magneto Resistance) element, for example. Instead of the AMR element, each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bmay be another magnetoresistance element, for example, a GMR (Giant Magneto Resistance) element, a TMR (Tunnel Magneto Resistance) element, a BMR (Ballistic Magneto Resistance) element, or a CMR (Colossal Magneto Resistance) element.

The second magnetoresistance element130ais magnetically shielded by the first magnet40and hardly detects a magnetic field in the Z-axis direction (vertical magnetic field) and a magnetic field in the X-axis and Y-axis directions (horizontal magnetic field). That is, the second magnetoresistance element130ais a fixed resistor. This will be discussed later. The first magnetoresistance element120ais a magneto-sensitive resistor whose electrical resistance changes in response to the application of an external magnetic field. That is, the first magnetoresistance element120adefines and functions as a magneto-sensitive element, and the second magnetoresistance element130adoes not define or function as a magneto-sensitive element. The resistance change rate of the second magnetoresistance element130ain response to an external magnetic field is preferably lower than that of the first magnetoresistance element120a, for example.

Similarly, the second magnetoresistance element130bis magnetically shielded by the first magnet40and hardly detects a magnetic field in the Z-axis direction (vertical magnetic field) and a magnetic field in the X-axis and Y-axis directions (horizontal magnetic field). That is, the second magnetoresistance elements130bis a fixed resistor. This will be discussed later. The first magnetoresistance element120bis a magneto-sensitive resistor whose electrical resistance changes in response to the application of an external magnetic field. That is, the first magnetoresistance element120bdefines and functions as a magneto-sensitive element, and the second magnetoresistance element130bdoes not define or function as a magneto-sensitive element. The resistance change rate of the second magnetoresistance element130bin response to an external magnetic field is preferably lower than that of the first magnetoresistance element120b, for example.

The first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bare electrically connected with each other by wiring provided on the semiconductor substrate110. More specifically, the first and second magnetoresistance elements120aand130aare connected in series with each other by wiring146, while the first and second magnetoresistance elements120band130bare connected in series with each other by wiring150.

On the semiconductor substrate110of the circuit substrate100, nodes140and141, a power supply terminal (Vcc)142, a ground terminal (Gnd)143, and an output terminal (Out)144are also provided.

Each of the first and second magnetoresistance elements120aand130bis connected to the node140. More specifically, the first magnetoresistance element120ais connected to the node140by wiring145, while the second magnetoresistance element130bis connected to the node140by wiring152.

Each of the first and second magnetoresistance elements120band130ais connected to the node141. More specifically, the first magnetoresistance element120bis connected to the node141by wiring149, while the second magnetoresistance element130ais connected to the node141by wiring148.

The wiring146is connected to the power supply terminal (Vcc)142into which a current is input. The wiring150is connected to the ground terminal (Gnd)143.

As shown inFIG. 5, the magnetic sensor1also includes a differential amplifier160, a temperature compensation circuit161, a latch/switch circuit162, and a CMOS (Complementary Metal Oxide Semiconductor) driver163. The differential amplifier160, the temperature compensation circuit161, the latch/switch circuit162, and the CMOS driver163are provided on the semiconductor substrate110.

The input terminals of the differential amplifier160are connected to the nodes140and141, while the output terminal is connected to the temperature compensation circuit161. The differential amplifier160is also connected to the power supply terminal (Vcc)142and the ground terminal (Gnd)143.

The output terminal of the temperature compensation circuit161is connected to the latch/switch circuit162. The temperature compensation circuit161is also connected to the power supply terminal (Vcc)142and the ground terminal (Gnd)143.

The output terminal of the latch/switch circuit162is connected to the CMOS driver163. The latch/switch circuit162is also connected to the power supply terminal (Vcc)142and the ground terminal (Gnd)143.

The output terminal of the CMOS driver163is connected to the output terminal (Out)144. The CMOS driver163is also connected to the power supply terminal (Vcc)142and the ground terminal (Gnd)143.

With the above-described circuitry of the magnetic sensor1, a potential difference is generated between the nodes140and141in accordance with the strength of an external magnetic field. When the potential difference exceeds a preset detection level, a signal is output from the output terminal (Out)144.

FIG. 6is a sectional view of a multilayer structure of a connecting portion between the magnetoresistance elements and the wiring on the circuit substrate of the magnetic sensor according to the first preferred embodiment of the present invention. InFIG. 6, only the connecting portion between a region R defining and functioning as the magnetoresistance elements and a region L defining and functioning as the wiring is shown.

As shown inFIG. 6, each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bis provided on the semiconductor substrate110made of Si, for example, including a SiO2layer or a Si3N4layer on the front surface. The first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bare formed as a result of a magnetic layer10including an Ni—Fe alloy provided on the semiconductor substrate110being patterned by ion milling. The thickness of the magnetic layer10is preferably about 0.04 μm, for example.

The wiring145,146,148,149,150, and152is formed as a result of a conductive layer20including Au or Al, for example, provided on the semiconductor substrate110being patterned by wet etching. The conductive layer20is positioned immediately on the top of the magnetic layer10in the region L defining and functioning as the wiring and is not provided in the region R defining and functioning as the magnetoresistance elements. As shown inFIG. 6, at the connecting portion between the region R defining and functioning as the magnetoresistance elements and the region L defining and functioning as the wiring, the end portion of the conductive layer20is positioned immediately on the top of the magnetic layer10.

The nodes140and141, the power supply terminal (Vcc)142, the ground terminal (Gnd)143, and the output terminal (Out)144are defined by the conductive layer20positioned immediately on the top of the semiconductor substrate110. That is, each of the nodes140and141, the power supply terminal (Vcc)142, the ground terminal (Gnd)143, and the output terminal (Out)144is a pad provided on the semiconductor substrate110.

A Ti layer, for example, which is not shown, is provided immediately on the top of the conductive layer20. The insulating layer30made of SiO2, for example, is provided to cover the magnetic layer10and the conductive layer20. That is, the insulating layer30covers the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130b.

FIG. 7is a plan view showing a pattern of each of the first magnetoresistance elements of the magnetic sensor according to the first preferred embodiment of the present invention. As shown inFIGS. 4 and 7, a pattern120of each of the first magnetoresistance elements120aand120bincludes four first patterns. The four first patterns are provided along the circumference of an imaginary circle C1and side by side one another in the radial direction of the imaginary circle C1and are connected with each other, as viewed from a direction perpendicular or substantially perpendicular to the insulating layer30. The direction perpendicular or substantially perpendicular to the insulating layer30is the Z-axis direction and is parallel or substantially parallel with a direction perpendicular or substantially perpendicular to the top surface of the semiconductor substrate110.

The four first patterns are located along an imaginary C-shaped feature C11, which is opened at a portion where the wiring146,148,150, and152is positioned, on the circumference of the imaginary circle C1. The four first patterns are C-shaped patterns121concentrically provided along the imaginary C-shaped feature C11and side by side one another in the radial direction of the imaginary circle C1.

The four C-shaped patterns121are connected with each other alternately at one end and at the other end starting from the central side of the imaginary circle C1. The C-shaped patterns121connected with each other at one end are connected with each other by a semi-circular pattern122. The C-shaped patterns121connected with each other at the other end are connected with each other by a semi-circular pattern123.

The pattern120of each of the first magnetoresistance elements120aand120bincludes two semi-circular patterns122and one semi-circular pattern123. Accordingly, the four C-shaped patterns121are connected in series with each other. The semi-circular patterns122and123do not have any linearly extending portions and are defined only by curved portions.

Among the four C-shaped patterns121, regarding the C-shaped pattern positioned at the outermost side from the center of the imaginary circle C1, the end portion of this C-shaped pattern which is not connected to the semi-circular pattern122is connected to the wiring145or149defined by the conductive layer20. Similarly, among the four C-shaped patterns121, regarding the C-shaped pattern positioned at the innermost side from the center of the imaginary circle C1, the end portion of this C-shaped pattern which is not connected to the semi-circular pattern122is connected to the wiring146or150defined by the conductive layer20. The position at which the conductive layer20is formed, which is the position at which the conductive layer20is connected to the end portion of the C-shaped pattern121, is able to be changed to adjust the electrical resistance of each of the first magnetoresistance elements120aand120b.

More specifically, at the connecting portion between the region R defining and functioning as the magnetoresistance elements and the region L defining and functioning as the wiring shown inFIG. 6, the conductive layer20extends toward the region R to increase the region L. The electrical resistance of the first magnetoresistance elements120aand120bis thus able to be reduced. Conversely, at the connecting portion between the region R defining and functioning as the magnetoresistance elements and the region L defining and functioning as the wiring, the conductive layer20retreats toward the region L to decrease the region L. The electrical resistance of the first magnetoresistance elements120aand120bis thus able to be increased.

The above-described adjustment of the electrical resistance of the first magnetoresistance elements120aand120bis performed by partially removing or adding the conductive layer20, and is thus preferably done before the insulating layer30is formed, for example.

Among the four C-shaped patterns121, the outer peripheral edge of the C-shaped pattern121positioned at the outermost side from the center of the imaginary circle C1is the outer peripheral edge of each of the first magnetoresistance elements120aand120b. Among the four C-shaped patterns121, the inner peripheral edge of the C-shaped pattern121positioned at the innermost side from the center of the imaginary circle C1is the inner peripheral edge of each of the first magnetoresistance elements120aand120b.

As shown inFIG. 4, the orientation of the circumferential direction of the first magnetoresistance element120aand that of the first magnetoresistance element120bare different from each other so that the orientations of the two imaginary C-shaped features C11become different. That is, the orientation of the circumferential direction of the pattern120of the first magnetoresistance element120aand that of the first magnetoresistance element120bare different from each other so that the orientation of the C-shaped patterns121of the first magnetoresistance element120aand that of the first magnetoresistance element120bbecome different.

In the first preferred embodiment, the orientation of the circumferential direction of the pattern120of the first magnetoresistance element120aand that of the first magnetoresistance element120bdiffer from each other by about 90°, for example, so that the orientation of the C-shaped patterns121of the first magnetoresistance element120aand that of the first magnetoresistance element120bbecome different from each other by about 90°.

FIG. 8is a plan view showing a pattern of each of the second magnetoresistance elements of the magnetic sensor according to the first preferred embodiment of the present invention. As shown inFIGS. 4 and 8, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the second magnetoresistance element130ais positioned at the central side of the imaginary circle C1and is surrounded by the first magnetoresistance element120a, while the second magnetoresistance element130bis positioned at the central side of the imaginary circle C1and is surrounded by the first magnetoresistance element120b. That is, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the second magnetoresistance element130ais located farther inward than the inner peripheral edge of the first magnetoresistance element120a, while the second magnetoresistance element130bis located farther inward than the inner peripheral edge of the first magnetoresistance element120b.

The second magnetoresistance element130ais connected to the wiring146and148defined by the conductive layer20provided from the central side of the imaginary circle C1to the outer side of the imaginary circle C1. The second magnetoresistance element130bis connected to the wiring150and152defined by the conductive layer20provided from the central side of the imaginary circle C1to the outer side of the imaginary circle C1.

Each of the second magnetoresistance elements130aand130bhas a double-spiral pattern130, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The double-spiral pattern130includes spiral patterns131and132and a reversed-S-shaped pattern133. The spiral pattern131is one of two second patterns, while the spiral pattern132is the other one of the two second patterns. The reversed-S-shaped pattern133connects the spiral patterns131and132at the central portion of the double-spiral pattern130. The reversed-S-shaped pattern133does not have any linearly extending portions and are defined only by curved portions.

The double-spiral pattern130has the same or substantially the same thickness as the pattern120. The spiral patterns131and132accordingly have the same or substantially the same thickness as each of the four C-shaped patterns121.

As shown inFIG. 8, the double-spiral pattern130is substantially point-symmetrical with respect to the center of the imaginary circle C1. That is, the double-spiral pattern130is rotationally symmetrical with respect to the center of the imaginary circle C1by about 180°.

As shown inFIG. 4, the orientation of the circumferential direction of the double-spiral pattern130of the second magnetoresistance element130aand that of the second magnetoresistance element130bare different from each other so that the orientation of the reversed-S-shaped pattern133of the second magnetoresistance element130aand that of the second magnetoresistance element130bbecome different.

In the first preferred embodiment, the orientation of the circumferential direction of the double-spiral pattern130of the second magnetoresistance element130aand that of the second magnetoresistance element130bare different from each other by about 90° so that the orientation of the reversed-S-shaped pattern133of the second magnetoresistance element130aand that of the second magnetoresistance element130bbecome different from each other by about 90°.

In the magnetic sensor1according to the first preferred embodiment, each of the first magnetoresistance elements120aand120bhas the C-shaped patterns121. The C-shaped patterns121are formed of arcs. The adjacent C-shaped patterns121are connected with each other by the semi-circular pattern122or123. Accordingly, the first magnetoresistance elements120aand120bdo not have any linearly extending portions, thus reducing the anisotropic characteristics in detecting a magnetic field.

Additionally, in the magnetic sensor1according to present preferred embodiment, the orientation of the circumferential direction of the pattern120of the first magnetoresistance element120aand that of the first magnetoresistance element120bare different from each other so that the orientation of the C-shaped patterns121of the first magnetoresistance element120aand that of the first magnetoresistance element120bbecome different, thus improving the isotropic characteristics in detecting a magnetic field.

In the magnetic sensor1according to the first preferred embodiment, each of the second magnetoresistance elements130aand130bhas the double-spiral pattern130. The double-spiral pattern130is formed principally by winding substantially circular-arc curved portions. The shape of a circular arc approximates a shape having an infinite number of corners of a polygon. Thus, the direction of a current flowing through the double-spiral pattern130covers about 360° in the horizontal direction. The horizontal direction is a direction parallel or substantially parallel with the top surface of the semiconductor substrate110.

In the magnetic sensor1according to the first preferred embodiment, the center of the double-spiral pattern130is the reversed-S-shaped pattern133defined only by curved portions. Accordingly, the second magnetoresistance elements130aand130bdo not have any linearly extending portions, thus reducing the anisotropic characteristics of the magnetoresistance effect.

In the magnetic sensor1according to the first preferred embodiment, the orientation of the circumferential direction of the double-spiral pattern130of the second magnetoresistance element130aand that of the second magnetoresistance element130bare different from each other so that the orientation of the reversed-S-shaped pattern133of the second magnetoresistance element130aand that of the second magnetoresistance element130bbecome different, thus improving the isotropic characteristics of the magnetoresistance effect.

As discussed above, the double-spiral pattern130is rotationally symmetrical with respect to the center of the imaginary circle C1by about 180°. Accordingly, the second magnetoresistance elements130aand130bslightly exhibit the anisotropic characteristics of the magnetoresistance effect.

To compensate for the anisotropic characteristics, the orientation of the circumferential direction of the double-spiral pattern130of the second magnetoresistance element130aand that of the second magnetoresistance element130bare different from each other. Accordingly, the anisotropic characteristics of the magnetoresistance effect of the second magnetoresistance element130aand that of the second magnetoresistance element130bare able to be offset from each other and be reduced to a smaller level.

If the orientation of the circumferential direction of the double-spiral pattern130of the second magnetoresistance element130aand that of the second magnetoresistance element130bdiffer from each other by about 90°, the anisotropic characteristics of the magnetoresistance effect of each of the second magnetoresistance elements130aand130bare able to be significantly reduced.

Accordingly, the direction in which the second magnetoresistance element130abecomes most sensitive coincides with that in which the second magnetoresistance element130bbecomes least sensitive, and the direction in which the second magnetoresistance element130abecomes least sensitive coincides with that in which the second magnetoresistance element130bbecomes most sensitive. As a result, the potential difference generated between the nodes140and141when an external magnetic field is applied to the magnetic sensor1is less likely to vary depending on the application direction of the external magnetic field.

The double-spiral pattern130includes a shape with a high density per unit area. With such a double-spiral pattern130, the pattern of each of the second magnetoresistance elements130aand130bprovided within the imaginary circle C1is able to be elongated to increase the resistance of the second magnetoresistance elements130aand130b. As the electrical resistance of the second magnetoresistance elements130aand130bis higher, the current consumed in the magnetic sensor1is able to be reduced by a greater amount.

As stated above, as a result of distributing the orientation of the current flowing through the double-spiral pattern130in the horizontal direction, the anisotropic characteristics of the magnetoresistance effect of each of the second magnetoresistance elements130aand130bis reduced. Thus, output variations of the magnetic sensor1when the external magnetic field is 0, which would be caused by the influence of residual magnetization, are able to be significantly reduced.

The double-spiral pattern130may be wound in the opposite direction, in which case, the central portion of the double-spiral pattern130is an S-shaped pattern defined only by curved portions. That is, the two spiral patterns are connected with each other by the S-shaped pattern.

In the magnetic sensor1according to the first preferred embodiment, the second magnetoresistance elements130aand130bare provided inward of the first magnetoresistance elements120aand120b, respectively, and thus the size of the magnetic sensor is able to be significantly reduced. Additionally, in the magnetic sensor1, it is not necessary to three-dimensionally lay the wiring to connect the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130b. Thus, the circuit substrate100is able to be manufactured with a simple manufacturing process.

In the magnetic sensor1according to the first preferred embodiment, the two first magnets40are provided above the insulating layer30and are provided side by side in the Y-axis direction. The thickness x of each first magnet40is preferably about 10 μm or greater, for example, and more preferably, about 20 μm to about 150 μm, for example. If the thickness x of the first magnet40is about 10 μm or greater, a vertical magnetic field deflected substantially in the horizontal direction by the first magnet40is able to be detected by each of the first magnetoresistance elements120aand120b. This will be discussed later. If the thickness x of the first magnet40is about 20 μm or greater, a vertical magnetic field is able to be more effectively deflected substantially in the horizontal direction by the first magnet40, so that the first magnetoresistance elements120aand120bare able to each detect a weaker vertical magnetic field. If the thickness x of the first magnet40is about 150 μm or smaller, the time needed to form the first magnet40is able to be reduced, and thus the mass-production of the magnetic sensors1is able to be maintained.

As shown inFIG. 4, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets40have an externally circular or substantially circular shape and are located in the regions farther inward than the outer peripheral edges of the first magnetoresistance elements120aand120b. The regions farther inward than the outer peripheral edges of the first magnetoresistance elements120aand120bare regions surrounded by the outer peripheral edges of the first magnetoresistance elements120aand120bwhen both ends of the outer peripheral edge of each of the first magnetoresistance elements120aand120bare connected with each other by an imaginary line, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. Preferably, for example, at least about one half, and more preferably, for example, at least about ⅔, of the region farther inward than the outer peripheral edge of each of the first magnetoresistance elements120aand120boverlaps the corresponding first magnet40, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In the first preferred embodiment, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets40are located in the regions farther inward than the inner peripheral edges of the first magnetoresistance elements120aand120b. The regions farther inward than the inner peripheral edges of the first magnetoresistance elements120aand120bare regions surrounded by the inner peripheral edges of the first magnetoresistance elements120aand120bwhen both ends of the inner peripheral edge of each of the first magnetoresistance elements120aand120bare connected with each other by an imaginary line, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The first magnets40may be each located in a region including the inner peripheral edge of the corresponding one of the first magnetoresistance elements120aand120band the area inward of the inner peripheral edge, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. Preferably, for example, at least about one half, and more preferably, for example, at least about ⅔, of the region farther inward than the inner peripheral edge of each of the first magnetoresistance elements120aand120boverlaps the corresponding first magnet40, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In the first preferred embodiment, the first magnets40are positioned concentrically with the outer peripheral edges of the first magnetoresistance elements120aand120b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In the first preferred embodiment, the first magnets40do not cover the first magnetoresistance elements120aand120b, but cover the second magnetoresistance elements130aand130b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The first magnets40are thus surrounded by the first magnetoresistance elements120aand120b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The first magnets40are made of a magnetic material having a high permeability and a high saturation magnetic flux density, for example, electromagnetic steel, mild steel, silicon steel, permalloy, supermalloy, a nickel alloy, an iron alloy, or ferrite. These magnetic materials preferably have low magnetic coercivity, for example.

If a magnetic material whose permeability increases at high temperatures and decreases at low temperatures, for example, an Fe-78Ni alloy, is preferably used as the magnetic material for the first magnets40, the temperature dependence of the resistance change rate of the first magnetoresistance elements120aand120bis able to be reduced.

The first magnets40are formed by plating, for example. A thin layer may be provided between the insulating layer30and the first magnets40.

A description will be provided of a first example in which the influence of the first magnet40on the distribution of a vertical magnetic field and that of a horizontal magnetic field is verified by simulations. In the first example, the exterior surface of the first magnet40was a cylinder having a diameter of about 140 μm and a thickness x of about 100 μm. The first magnet40included permalloy. The first magnets40were provided over the second magnetoresistance elements130aand130band did not cover the first magnetoresistance elements120aand120b, but did cover the second magnetoresistance elements130aand130b. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the inner peripheral edges of the first magnetoresistance elements120aand120bwere located adjacent to and outward of the outer peripheral edges of the first magnets40. The strength of a vertical magnetic field or a horizontal magnetic field to be applied to the magnetic sensor1was about 30 mT.

FIG. 9is a magnetic flux diagram showing a distribution of the magnetic flux density when a vertical magnetic field is applied to the magnetic sensor according to the first example.FIG. 10is a magnetic flux diagram showing a distribution of the magnetic flux density when a horizontal magnetic field is applied to the magnetic sensor according to the first example.FIG. 11is a graph showing a relationship between the distance from the outer peripheral edge of the first magnet in the horizontal direction and the magnetic field strength in the horizontal direction when a vertical magnetic field or a horizontal magnetic field is applied to the magnetic sensor according to the first example.FIGS. 9 and 10show the magnetic sensor1as viewed from the horizontal direction and show only the first magnet40, the first magnetoresistance elements120aand120b, and the second magnetoresistance elements130aand130b.

InFIG. 11, the vertical axis indicates the magnetic field strength (mT) in the horizontal direction, while the horizontal axis indicates the distance (μm) from the outer peripheral edge of the first magnet in the horizontal direction. Regarding the distance from the outer peripheral edge of the first magnet in the horizontal direction, the distance outward from the outer peripheral edge of the first magnet40is represented by a positive value, while the distance inward from the outer peripheral edge of the first magnet40is represented by a negative value. The distribution of the magnetic field strength in the horizontal direction when a vertical magnetic field is applied is indicated by the solid line V, while that when a horizontal magnetic field is applied is indicated by the solid line H.

As shown inFIG. 9, when a vertical magnetic field heading from upward to downward was applied to the magnetic sensor of the first example, the magnetic flux was attracted and concentrated toward the first magnet40having a high permeability on its top surface. The magnetic flux entering the first magnet40passed through the first magnet40in the vertical direction and was output from its bottom surface while diffusing.

Accordingly, the magnetic field was applied substantially in the vertical direction to each of the second magnetoresistance elements130aand130bpositioned immediately under the first magnet40. The second magnetoresistance elements130aand130bhardly detected the vertical magnetic field. In contrast, the magnetic field deflected substantially in the horizontal direction, as indicated by the arrows inFIG. 9, was applied to each of the first magnetoresistance elements120aand120bpositioned downward from the outer peripheral edge of the first magnet40. The first magnetoresistance elements120aand120bwere thus able to detect the vertical magnetic field as a magnetic field deflected substantially in the horizontal direction.

As shown inFIG. 10, when a horizontal magnetic field heading from left to right was applied to the magnetic sensor of the first example, the magnetic flux was attracted and concentrated toward the first magnet40on its left surface. The magnetic flux entering the first magnet40passed through the first magnet40in the horizontal direction and was output from its right surface while diffusing.

Accordingly, the horizontal-direction magnetic field was hardly applied to each of the second magnetoresistance elements130aand130bpositioned immediately under the first magnet40, as indicated by the arrow inFIG. 10. The second magnetoresistance elements130aand130bthus hardly detected the horizontal magnetic field. In contrast, the horizontal-direction magnetic field was applied to each of the first magnetoresistance elements120aand120bpositioned downward from the outer peripheral edge of the first magnet40. The first magnetoresistance elements120aand120bwere thus able to detect the horizontal magnetic field.

FIG. 11shows that, in a certain area of positions outward of the outer peripheral edge of the first magnet40, the horizontal-direction magnetic field strength exceeds about 30 mT, which is the strength of the vertical magnetic field or the horizontal magnetic field applied to the magnetic sensor1. More specifically, in the case of the application of the vertical magnetic field, the horizontal-direction magnetic field strength exceeds about 30 mT, which is the strength of the applied vertical magnetic field, in the area from the position separated inward from the outer peripheral edge of the first magnet40by about 2 μm to the position separated outward from the outer peripheral edge of the first magnet40by about 10 μm. In the case of the application of the horizontal magnetic field, too, the horizontal-direction magnetic field strength exceeds about 30 mT, which is the strength of the applied horizontal magnetic field, at positions separated outward from the outer peripheral edge of the first magnet40. The magnetic field attracted and concentrated toward the first magnet40was output from the first magnet40in the horizontal direction at a high magnetic field strength. This horizontal-direction magnetic field having a high magnetic field strength was applied to the first magnetoresistance elements120aand120b.

FIG. 11shows that the horizontal-direction magnetic field strength is about ⅓ or lower of the strength of the applied vertical magnetic field or horizontal magnetic field, which is about 30 mT, at positions separated inward from the outer peripheral edge of the first magnet40by about 7 μm or greater. Thus, the second magnetoresistance elements130aand130bare preferably provided at positions separated inward from the outer peripheral edge of the first magnet40by about 7 μm or greater, for example.

As described above, the horizontal-direction magnetic field strength exceeds about 30 mT, which is the strength of the applied vertical magnetic field or horizontal magnetic field, in the area from the position separated inward from the outer peripheral edge of the first magnet40by about 2 μm to the position separated outward from the outer peripheral edge of the first magnet40by about 10 μm. At least a portion of each of the first magnetoresistance elements120aand120bis preferably provided in at least a portion of this area, for example. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, each of the first magnetoresistance elements120aand120bprovided in this area surrounds preferably, for example, at least about ½, and more preferably, for example, at least about ⅔, of the entirety of the outer peripheral portion of the first magnet40.

As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets40are located concentrically with the outer peripheral edges of the first magnetoresistance elements120aand120band are surrounded by the first magnetoresistance elements120aand120b. Accordingly, the horizontal-direction magnetic field output outward from the outer peripheral edge of the first magnet40was applied to each of the first magnetoresistance elements120aand120bsubstantially equally in the circumferential direction.

The results of the first example show that the magnetic sensor1of the first preferred embodiment of the present invention is able to significantly increase the detection sensitivity of the first magnetoresistance elements120aand120bfor a vertical magnetic field while reducing a change in the resistance of the second magnetoresistance elements130aand130bin response to a vertical magnetic field. That is, the first magnetoresistance elements120aand120bis able to detect a weak vertical magnetic field. The results of the first example also show that the magnetic sensor1of the first preferred embodiment of the present invention is able to significantly increase the detection sensitivity of the first magnetoresistance elements120aand120bfor a horizontal magnetic field while reducing a change in the resistance of the second magnetoresistance elements130aand130bin response to a horizontal magnetic field. That is, the first magnetoresistance elements120aand120bare able to detect a weak horizontal magnetic field.

A description will now be provided of a second example. In the second example, the influence of the thickness of the first magnet on the relationship between the distance from the outer peripheral edge of the first magnet in the horizontal direction and the horizontal-direction magnetic field strength when a vertical magnetic field was applied to a magnetic sensor was verified by simulations.

FIG. 12is a graph showing the influence of the thickness of the first magnet on the relationship between the distance from the outer peripheral edge of the first magnet in the horizontal direction and the horizontal-direction magnetic field strength when a vertical magnetic field is applied to the magnetic sensor according to the second example. InFIG. 12, the vertical axis indicates the magnetic field strength (mT) in the horizontal direction, while the horizontal axis indicates the distance (μm) from the outer peripheral edge of the first magnet in the horizontal direction.FIG. 13is a graph showing a relationship between the thickness of the first magnet and the distance outward from the outer peripheral edge of the first magnet in the horizontal direction at which the horizontal-direction magnetic field strength reaches about ⅓ of its peak value. InFIGS. 12 and 13, regarding the distance from the outer peripheral edge of the first magnet in the horizontal direction, the distance outward from the outer peripheral edge of the first magnet40is represented by a positive value, while the distance inward from the outer peripheral edge of the first magnet40is represented by a negative value.

In the second example, the exterior surface of the first magnet40was a cylinder having a diameter of about 140 μm. As the thickness x of the first magnet40, five values were set, for example, about 10 μm, about 20 μm, about 50 μm, about 100 μm, and about 150 μm. The first magnet40was made of permalloy. The first magnet40was provided similarly to the first example. The strength of a vertical magnetic field to be applied to the magnetic sensor was about 30 mT.

As shown inFIG. 12, as the thickness x of the first magnet40becomes greater, the peak value of the horizontal-direction magnetic field strength becomes higher. As long as the permeability of permalloy is in a range of about 10000 to about 100000, the result shown in the graph ofFIG. 12is not considerably influenced by the permeability of the first magnet40and remains substantially the same even when the permeability of the first magnets40is changed.

To provide stable output from the bridge circuit of the magnetic sensor1, the strength of a horizontal-direction magnetic field applied to the first magnetoresistance elements120aand120bis preferably, for example, about ⅓ or higher of its peak value, while the strength of a horizontal-direction magnetic field applied to the second magnetoresistance elements130aand130bis preferably, for example, about 1/10 or lower of its peak value.

As shown inFIG. 12, regardless of the thickness x of the first magnet40, the horizontal-direction magnetic field strength is about ⅓ or higher of its peak value in the area of the positions separated inward from the outer peripheral edge of the first magnet40by about 2 μm or smaller.

As shown inFIG. 13, as the thickness x of the first magnet40becomes thicker, the distance y outward from the outer peripheral edge of the first magnet40in the horizontal direction at which the horizontal-direction magnetic field strength reaches about ⅓ of its peak value is greater. The relationship between the thickness x and the distance y is represented by the following approximate expression (I).
y=−0.0008x2+0.2495x+6.6506  (I)

That is, in the area within y μm outward from the outer peripheral edge of the first magnet40in the horizontal direction, the horizontal-direction magnetic field strength becomes about ⅓ or higher of its peak value. Thus, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the horizontal-direction magnetic field strength becomes about ⅓ or higher of its peak value in the area from the position separated inward from the outer peripheral edge of the first magnet40by about 2 μm to the position separated outward from the outer peripheral edge of the first magnet40by y μm indicated in the above-described expression (I).

As shown inFIG. 12, regardless of the thickness x of the first magnet40, the horizontal-direction magnetic field strength is about 1/10 or lower of its peak value in the area inward from the outer peripheral edge of the first magnet40by about 7 μm or greater. That is, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the horizontal-direction magnetic field strength becomes about 1/10 or lower of its peak value in the area from the center of the first magnet40to the position separated inward from the outer peripheral edge of the first magnet40by about 7 μm.

As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, at least a portion of each of the first magnetoresistance elements120aand120bis preferably located, for example, in at least a portion of the area from the position separated inward from the outer peripheral edge of the first magnet40by about 2 μm to the position separated outward from the outer peripheral edge of the first magnet40by y μm defined by the above-described expression (I).

As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, each of the second magnetoresistance elements130aand130bis preferably located, for example, in the area from the center of the first magnet40to the position separated inward from the outer peripheral edge of the first magnet40by about 7 μm.

As described above, the magnetic sensor1according to the first preferred embodiment of the present invention is able to detect a vertical magnetic field and a horizontal magnetic field with high sensitivity. In the magnetic sensor1according to the first preferred embodiment of the present invention, each of the first magnetoresistance elements120aand120bincludes concentrically provided multiple first patterns, thus improving the isotropic characteristics in detecting a horizontal magnetic field.

In the first preferred embodiment, the double-spiral patterns130of the second magnetoresistance elements130aand130bare formed with the same or substantially the same thickness as the patterns120of the first magnetoresistance elements120aand120b. Accordingly, even if the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bare formed in the same step, variations in the processing precision of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bare reduced. Thus, the output characteristics of the magnetic sensor1are able to be stabilized.

However, the double-spiral patterns130may be narrower than the patterns120. Accordingly, the magnetoresistance effect of the second magnetoresistance elements130aand130bbecomes even smaller than that of the first magnetoresistance elements120aand120b. As a result, the magnetoresistance effect of the second magnetoresistance elements130aand130bis lessened, thus considerably decreasing the resistance change rate of the second magnetoresistance elements130aand130b.

Accordingly, the potential difference generated between the nodes140and141when an external magnetic field is applied to the magnetic sensor1is able to be significantly increased, thus improving the detection sensitivity of the magnetic sensor1. Additionally, since the electrical resistance of the second magnetoresistance elements130aand130bis high, there is only a relatively small decrease in the potential difference generated between the nodes140and141when an external magnetic field having a high magnetic field strength is applied to the magnetic sensor1, thus stabilizing the output characteristics of the magnetic sensor1.

In the present preferred embodiment, the second magnetoresistance elements130aand130bare magnetically shielded by the first magnets40and hardly detect vertical magnetic fields and horizontal magnetic fields. The resistance change rate of the second magnetoresistance elements130aand130bmay not necessarily be smaller than that of the first magnetoresistance elements120aand120b.

In the magnetic sensor1according to the first preferred embodiment of the present invention, the first conductor60and the first stress relaxer80are provided between the first magnet40and the circuit substrate100. The first conductor60includes the first base section61and the first narrow section62, and the first narrow section62contacts the circuit substrate100. More specifically, the first narrow section62contacts the insulating layer30provided on the front layer of the circuit substrate100. The first stress relaxer80is provided in a gap between the first base section61and the insulating layer30. The first stress relaxer80is made of a material different from that of the first conductor60. The first stress relaxer80is preferably made of at least one of, for example, a material having a lower adhesiveness, a material having a lower elastic modulus, and a material having a lower tensile strength than the material of the first conductor60.

Accordingly, the contact area between the first conductor60and the circuit substrate100is able to be significantly reduced, thus decreasing a stress applied from the first magnet40to each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bvia the first conductor60. The first stress relaxer80is provided immediately under the outer peripheral portion of the first base section61. The first stress relaxer80is able to thus relax a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to be applied to the circuit substrate100.

More specifically, if the first stress relaxer80is made of a material having a lower adhesiveness than the material of the first conductor60, when the first stress relaxer80is subjected to a stress caused by a distortion produced at the outer peripheral portion of the first magnet40, it separates from a component or element adjacent to the first stress relaxer80. Accordingly, transmission of the stress to the adjacent component or element via the first stress relaxer80is significantly reduced or prevented.

If the first stress relaxer80is made of a material having a lower elastic modulus than the material of the first conductor60, when the first stress relaxer80is subjected to a stress caused by a distortion produced at the outer peripheral portion of the first magnet40, it elastically deforms to absorb the stress. Accordingly, transmission of the stress to a component or element adjacent to the first stress relaxer80via the first stress relaxer80is significantly reduced or prevented.

If the first stress relaxer80is made of a material having a lower tensile strength than the material of the first conductor60, when the first stress relaxer80is subjected to a stress caused by a distortion produced at the outer peripheral portion of the first magnet40, it cracks and separates from a component or element adjacent to the first stress relaxer80. Accordingly, transmission of the stress to the adjacent component or element via the first stress relaxer80is significantly reduced or prevented.

Thus, the first stress relaxer80relaxes a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to be applied from the first magnet40to each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bvia the first conductor60. Accordingly, a decrease in the output accuracy of the magnetic sensor1is able to be regulated. It is also less likely that the insulating layer30cracks due to a stress applied from the first magnet40to the insulating layer30via the first conductor60. Thus, the reliability of the magnetic sensor1is able to be maintained.

In the first preferred embodiment, a gap is provided between the first base section61and the insulating layer30all around the outer peripheral portion of the first conductor60, and the first stress relaxer80is provided in the entirety or substantially the entirety of this gap. Accordingly, the application of a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to the circuit substrate100via the first conductor60is able to be significantly reduced.

As described above, the magnetic sensor1according to the first preferred embodiment of the present invention provides high isotropic characteristics in detecting a horizontal magnetic field and is also able to detect a weak vertical magnetic field by using magnetoresistance elements. The magnetic sensor1is able to also regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements. According to the thickness x of the first magnet40for a portion of the first magnet40positioned on the first conductor60, the verification results based on the first and second examples are able to be utilized.

Second Preferred Embodiment

A magnetic sensor according to a second preferred embodiment of the present invention will be described below with reference to the drawing. The magnetic sensor according to the second preferred embodiment of the present invention is different from the magnetic sensor1of the first preferred embodiment of the present invention mainly in the first conductor and the arrangement of the stress relaxer. An explanation of elements similar to those of the magnetic sensor1of the first preferred embodiment of the present invention will not be repeated.

FIG. 14is a sectional view showing the magnetic sensor according to the second preferred embodiment of the present invention. InFIG. 14, the magnetic sensor as viewed from the same or substantially the same direction as that inFIG. 2is shown.

As shown inFIG. 14, in a magnetic sensor1aaccording to the second preferred embodiment of the present invention, a first conductor60ais provided on the circuit substrate100. The first conductor60aincludes a first base section61and a first narrow section62. In the first conductor60a, the first base section61and the first narrow section62are provided side by side in the direction perpendicular or substantially perpendicular to the insulating layer30. In the second preferred embodiment, the first narrow section62of the first conductor60ais positioned at the end portion of the first conductor60acloser to the first magnet40in the direction perpendicular or substantially perpendicular to the insulating layer30. That is, the first narrow section62of the first conductor60acontacts the first magnet40.

The first narrow section62in the first conductor60aprovides a gap partially between the first base section61and the first magnet40. In the second preferred embodiment, the gap is provided between the first base section61and the first magnet40all around the outer peripheral portion of the first conductor60a. The first stress relaxer80is provided in this gap.

The first stress relaxer80is provided in a region which is surrounded by the exterior surface of the first narrow section62and also by the exterior surface of the first base section61, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. In the second preferred embodiment, the first stress relaxer80is sandwiched between the first base section61and the first magnet40. The first stress relaxer80is located immediately under the outer peripheral portion of the first magnet40. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first stress relaxer80has a ring shape.

In the magnetic sensor1aaccording to the second preferred embodiment of the present invention, the first conductor60aand the first stress relaxer80are provided between the first magnet40and the circuit substrate100. The first conductor60aincludes the first base section61and the first narrow section62, and the first narrow section62contacts the first magnet40. The first stress relaxer80is provided in a gap between the first base section61and the first magnet40. The first stress relaxer80is a component or element including a material different from that of the first conductor60a. The first stress relaxer80is preferably made of, for example, at least one of a material having a lower adhesiveness, a material having a lower elastic modulus, and a material having a lower tensile strength than the material of the first conductor60a.

Accordingly, the contact area between the first conductor60aand the first magnet40is able to be significantly reduced, thus decreasing a stress applied from the first magnet40to each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bvia the first conductor60a. The first stress relaxer80is provided immediately under the outer peripheral portion of the first magnet40. The first stress relaxer80is able to thus relax a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to be applied to the circuit substrate100.

Thus, the first stress relaxer80is able to relax a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to be applied from the first magnet40to each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bvia the first conductor60a. Accordingly, a decrease in the output accuracy of the magnetic sensor1ais able to be regulated. It is also less likely that the insulating layer30cracks due to a stress applied from the first magnet40to the insulating layer30via the first conductor60a. Thus, the reliability of the magnetic sensor1ais able to be maintained.

In the second preferred embodiment, a gap is provided between the first base section61and the first magnet40all around the outer peripheral portion of the first conductor60a, and the first stress relaxer80is provided in the entirety or substantially the entirety of the gap. Thus, the application of a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to the circuit substrate100via the first conductor60ais able to be significantly reduced.

Third Preferred Embodiment

A magnetic sensor according to a third preferred embodiment of the present invention will be described below with reference to the drawing. The magnetic sensor according to the third preferred embodiment of the present invention is different from the magnetic sensor1of the first preferred embodiment of the present invention mainly in the first conductor and the structure and location of the stress relaxer. An explanation of elements similar to those of the magnetic sensor1of the first preferred embodiment of the present invention will not be repeated.

FIG. 15is a front view showing the magnetic sensor according to the third preferred embodiment of the present invention. InFIG. 15, the magnetic sensor as viewed from the same or substantially the same direction as that inFIG. 2is shown.

As shown inFIG. 15, in a magnetic sensor1baccording to the third preferred embodiment of the present invention, a first conductor60bis provided on the circuit substrate100. The first conductor60bincludes first base sections61and a first narrow section62. In the first conductor60b, the first base sections61and the first narrow section62are provided side by side in the direction perpendicular or substantially perpendicular to the insulating layer30. In the third preferred embodiment, the first base section61of the first conductor60bis located at the end portion of the first conductor60bcloser to the insulating layer and that closer to the first magnet40in the direction perpendicular or substantially perpendicular to the insulating layer30. The first narrow section62of the first conductor60bis sandwiched between the first base sections61of the first conductor60bin the direction perpendicular or substantially perpendicular to the insulating layer30.

The provision of the first narrow section62in the first conductor60bprovides a gap partially between the first base sections61. In the third preferred embodiment, the gap is provided between the first base sections61all around the outer peripheral portion of the first conductor60b. The first stress relaxer80is provided in the gap.

The first stress relaxer80is provided in a region which is surrounded by the exterior surface of the first narrow section62and also by the exterior surface of the first base section61, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. In the third preferred embodiment, the first stress relaxer80is sandwiched between the first base sections61. The first stress relaxer80is located immediately under the outer peripheral portion of the first base section61positioned at the end portion of the first base sections61closer to the first magnet40. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first stress relaxer80has a ring shape.

In the magnetic sensor1baccording to the third preferred embodiment of the present invention, the first conductor60band the first stress relaxer80are provided between the first magnet40and the circuit substrate100. The first conductor60bincludes the first narrow section62between the first base sections61. The first stress relaxer80is provided in a gap between the first base sections61. The first stress relaxer80includes a material different from that of the first conductor60b. The first stress relaxer80is preferably made of, for example, at least one of a material having a lower adhesiveness, a material having a lower elastic modulus, and a material having a lower tensile strength than the material of the first conductor60b.

Accordingly, the first stress relaxer80is able to relax a stress within the first conductor60b, thus decreasing a stress applied from the first magnet40to each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bvia the first conductor60b. The first stress relaxer80is provided immediately under the outer peripheral portion of the first base section61positioned at the end portion of the first conductor60bcloser to the first magnet40. Thus, the first stress relaxer80relaxes a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to be applied to the circuit substrate100.

Thus, the first stress relaxer80relaxes a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to be applied from the first magnet40to each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130bvia the first conductor60b. Accordingly, a decrease in the output accuracy of the magnetic sensor1bis able to be regulated. It is also less likely that the insulating layer30cracks due to a stress applied from the first magnet40to the insulating layer30via the first conductor60b. Thus, the reliability of the magnetic sensor1bis able to be maintained.

In the third preferred embodiment, a gap is provided between the first base sections61all around the outer peripheral portion of the first conductor60b, and the first stress relaxer80is provided in the entirety or substantially the entirety of this gap. Thus, the application of a stress caused by a distortion produced at the outer peripheral portion of the first magnet40to the circuit substrate100via the first conductor60bis able to be significantly reduced.

Fourth Preferred Embodiment

A magnetic sensor according to a fourth preferred embodiment of the present invention will be described below with reference to the drawing. The magnetic sensor according to the fourth preferred embodiment of the present invention is different from the magnetic sensor1of the first preferred embodiment of the present invention mainly in the first magnet and the omission of the first conductor. An explanation of elements similar to those of the magnetic sensor1of the first preferred embodiment of the present invention will not be repeated.

FIG. 16is a sectional view showing the magnetic sensor according to the fourth preferred embodiment of the present invention. InFIG. 16, the magnetic sensor as viewed from the same or substantially the same direction as that inFIG. 2is shown.

As shown inFIG. 16, in a magnetic sensor1caccording to the fourth preferred embodiment of the present invention, a first magnet40ais provided on the circuit substrate100. The first magnet40aincludes a first base section41and a first narrow section42. The area of the exterior surface of the first narrow section42is smaller than that of the first base section41, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. In the first magnet40a, the first base section41and the first narrow section42are provided side by side in the direction perpendicular or substantially perpendicular to the insulating layer30. In the fourth preferred embodiment, the first narrow section42of the first magnet40ais positioned at the end portion of the first magnet40acloser to the insulating layer30in the direction perpendicular or substantially perpendicular to the insulating layer30. That is, the first narrow section42of the first magnet40acontacts the circuit substrate100.

As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the exterior surface of each of the first base section41and the first narrow section42is circular. The diameter of the exterior surface of the first narrow section42is smaller than that of the first base section41. The first base section41and the first narrow section42are provided substantially coaxially. The first base section41is not restricted to the above-described shape and may have an elliptical or polygonal shape, for example. The first narrow section42is not restricted to the above-described shape and may have any shape as long as the area of the exterior surface as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30is smaller than that of the first base section41.

The first narrow section42in the first magnet40aprovides a gap partially between the first base section41and the circuit substrate100. In the fourth preferred embodiment, the gap is provided between the first base section41and the circuit substrate100all around the outer peripheral portion of the first magnet40a. The first stress relaxer80is provided in the gap.

With a view to decreasing the distance between the first magnet40aand the circuit substrate100, the thickness of the first narrow section42in the Z-axis direction is preferably about 2.0 μm or smaller, for example. As the distance between the first base section41of the first magnet40aand the circuit substrate100is smaller, the magnetic shielding function of the first magnet40ais able to be provided more effectively.

To form the first narrow section42, patterning with a resist or etching with a sacrificial layer, for example, may be utilized.

The first stress relaxer80is provided in a region which is surrounded by the exterior surface of the first narrow section42and also by the exterior surface of the first base section41, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. In the fourth preferred embodiment, the first stress relaxer80is sandwiched between the first base section41and the insulating layer30. The first stress relaxer80is located immediately under the outer peripheral portion of the first base section41. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first stress relaxer80has a ring shape.

The first stress relaxer80includes a material different from that of the first magnet40a. The first stress relaxer80is preferably made of, for example, at least one of a material having a lower adhesiveness, a material having a lower elastic modulus, and a material having a lower tensile strength than the material of the first magnet40a.

In the magnetic sensor1caccording to the fourth preferred embodiment of the present invention, the first narrow section42of the first magnet40acontacts the circuit substrate100. Thus, the contact area between the first magnet40aand the circuit substrate100is able to be reduced, thus decreasing a stress applied from the first magnet40ato each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130b. The first stress relaxer80is provided immediately under the outer peripheral portion of the first base section41. Thus, the first stress relaxer80thus relaxes a stress caused by a distortion produced at the outer peripheral portion of the first magnet40ato be applied to the circuit substrate100.

Thus, the first stress relaxer80relaxes a stress caused by a distortion produced at the outer peripheral portion of the first magnet40ato be applied from the first magnet40ato each of the first magnetoresistance elements120aand120band the second magnetoresistance elements130aand130b. Accordingly, a decrease in the output accuracy of the magnetic sensor1cis able to accordingly be regulated. It is also less likely that the insulating layer30cracks due to a stress applied from the first magnet40ato the insulating layer30. Thus, the reliability of the magnetic sensor1cis able to be maintained.

In the fourth preferred embodiment, a gap is provided between the first base section41of the first magnet40aand the circuit substrate100all around the outer peripheral portion of the first magnet40a, and the first stress relaxer80is provided in the entirety or substantially the entirety of the gap. Thus, the application of a stress caused by a distortion produced at the outer peripheral portion of the first magnet40ato the circuit substrate100is able to be significantly reduced. According to the thickness x of the first magnet40afor the first base section41, the verification results based on the first and second examples are able to be utilized.

Fifth Preferred Embodiment

A magnetic sensor according to a fifth preferred embodiment of the present invention will be described below with reference to the drawings. The magnetic sensor according to the fifth preferred embodiment of the present invention is different from the magnetic sensor1of the first preferred embodiment of the present invention mainly in the pattern of second magnetoresistance elements. An explanation of elements similar to those of the magnetic sensor1of the first preferred embodiment of the present invention will not be repeated.

FIG. 17is a plan view of the magnetic sensor according to the fifth preferred embodiment of the present invention.FIG. 18is a plan view showing a pattern of a second magnetoresistance element of the magnetic sensor according to the fifth preferred embodiment of the present invention. As shown inFIG. 17, a magnetic sensor2according to the fifth preferred embodiment of the present invention includes a circuit substrate200and two first magnets40provided above the circuit substrate200. In the magnetic sensor2according to the fifth preferred embodiment of the present invention, on the circuit substrate200, two first conductors are provided. A first stress relaxer is provided along a portion of each of the first conductors. The first magnets40cover the associated first conductors, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

As shown inFIGS. 17 and 18, a pattern of each of first magnetoresistance elements120aand120bof the magnetic sensor2according to the fifth preferred embodiment of the present invention includes three first patterns. The three first patterns are provided along the circumference of an imaginary circle C2and side by side one another in the radial direction of the imaginary circle C2and are connected with each other, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The three first patterns are located along an imaginary C-shaped feature C21, which is opened at a portion where wiring146,148,150, and152is positioned, on the circumference of the imaginary circle C2. The three first patterns are C-shaped patterns provided along the imaginary C-shaped feature C21and side by side one another in the radial direction of the imaginary circle C2.

As shown inFIG. 17, the orientation of the circumferential direction of the first magnetoresistance element120aand that of the first magnetoresistance element120bare different from each other so that the orientations of the two imaginary C-shaped features C21become different. That is, the orientation of the circumferential direction of the pattern of the first magnetoresistance element120aand that of the first magnetoresistance element120bare different from each other so that the orientation of the circumferential direction of the C-shaped patterns of the first magnetoresistance element120aand that of the first magnetoresistance element120bbecome different.

In the fifth preferred embodiment, the orientation of the circumferential direction of the pattern of the first magnetoresistance element120aand that of the first magnetoresistance element120bdiffer from each other by about 90°, for example, so that the orientation of the C-shaped patterns of the first magnetoresistance element120aand that of the first magnetoresistance element120bbecome different from each other by about 90°.

As shown inFIGS. 17 and 18, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, a second magnetoresistance element230ais positioned at the central side of the imaginary circle C2and is surrounded by the first magnetoresistance element120a, while a second magnetoresistance element230bis positioned at the central side of the imaginary circle C2and is surrounded by the first magnetoresistance element120b. That is, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the second magnetoresistance element230ais located farther inward than the inner peripheral edge of the first magnetoresistance element120a, while the second magnetoresistance element230bis located farther inward than the inner peripheral edge of the first magnetoresistance element120b.

Each of the second magnetoresistance elements230aand230bincludes a pattern230. The pattern230includes fourteen semi-circular patterns231, which are second patterns, provided along the circumference of the imaginary circle C2line-symmetrically to each other and side by side one another in the radial direction of the imaginary circle C2. The pattern230preferably has the same or substantially the same thickness as that of the pattern120of each of the first magnetoresistance elements120aand120b. However, the pattern230may be thinner than the pattern120.

The fourteen semi-circular patterns231are connected with each other alternately at one end and at the other end starting from inward. The semi-circular patterns231connected with each other at one end are connected with each other by a semi-circular pattern232. The semi-circular patterns231connected with each other at the other end are connected with each other by a semi-circular pattern233. The semi-circular patterns231positioned at the innermost side line-symmetrically to each other are connected with each other at one end by a linearly extending portion234. The length of the linearly extending portion234is preferably shorter than about 10 μm, for example.

The pattern230of each of the second magnetoresistance elements230aand230bincludes the six semi-circular patterns232, the six semi-circular patterns233, and the linearly extending portion234. Accordingly, the fourteen semi-circular patterns231are connected in series with each other. The semi-circular patterns232and233do not have any linearly extending portions and are defined only by curved portions.

In the magnetic sensor2according to the fifth preferred embodiment, each of the second magnetoresistance elements230aand230bincludes the semi-circular patterns231. The semi-circular patterns231are formed of arcs. The two adjacent semi-circular patterns231are connected with each other by the semi-circular pattern232or233. Each of the second magnetoresistance elements230aand230bincludes the linearly extending portion234preferably having a length shorter than about 10 μm, for example. Thus, the anisotropic characteristics in detecting a magnetic field are able to be significantly reduced.

The orientation of the circumferential direction of the pattern230of the second magnetoresistance element230aand that of the second magnetoresistance element230bare different from each other. In the fifth preferred embodiment, the orientation of the circumferential direction of the pattern230of the second magnetoresistance element230aand that of the second magnetoresistance element230bare different from each other by about 90°, for example. Accordingly, the anisotropic characteristics of the magnetoresistance effect of the second magnetoresistance element230aand that of the second magnetoresistance element230bare able to be offset from each other and be reduced to a smaller level.

In the magnetic sensor2according to the fifth preferred embodiment, the second magnetoresistance elements230aand230bare provided inward of the first magnetoresistance elements120aand120b, respectively, and thus the size of the magnetic sensor is able to be significantly reduced. Additionally, in the magnetic sensor2, too, it is not necessary to three-dimensionally lay the wiring to connect the first magnetoresistance elements120aand120band the second magnetoresistance elements230aand230b. Hence, the circuit substrate200is able to be manufactured with a simple manufacturing process.

As shown inFIG. 17, the first magnets40do not cover the first magnetoresistance elements120aand120b, but cover the second magnetoresistance elements230aand230b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

The magnetic sensor2according to the fifth preferred embodiment is also able to detect a vertical magnetic field and a horizontal magnetic field with high sensitivity. In the magnetic sensor2according to the fifth preferred embodiment of the present invention, each of the first magnetoresistance elements120aand120bincludes concentrically provided multiple first patterns, thus improving the isotropic characteristics in detecting a horizontal magnetic field.

In the fifth preferred embodiment, the second magnetoresistance elements230aand230bare magnetically shielded by the first magnets40and hardly detect vertical magnetic fields and horizontal magnetic fields. The resistance change rate of the second magnetoresistance elements230aand230bmay not necessarily be smaller than that of the first magnetoresistance elements120aand120b.

The magnetic sensor2according to the fifth preferred embodiment of the present invention also provides high isotropic characteristics in detecting a horizontal magnetic field and is also able to detect a weak vertical magnetic field by using magnetoresistance elements. The magnetic sensor2is able to also regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements.

Sixth Preferred Embodiment

A magnetic sensor according to a sixth preferred embodiment of the present invention will be described below with reference to the drawings. The magnetic sensor according to the sixth preferred embodiment of the present invention is different from the magnetic sensor1of the first preferred embodiment of the present invention mainly in the patterns of the first and second magnetoresistance elements, the structure and location of the second magnetoresistance elements, and the addition of second conductors. An explanation of elements similar to those of the magnetic sensor1of the first preferred embodiment of the present invention will not be repeated.

FIG. 19is a perspective view showing the magnetic sensor according to the sixth preferred embodiment of the present invention.FIG. 20is a sectional view of the magnetic sensor inFIG. 19, as viewed from the direction indicated by the arrow of line XX-XX inFIG. 19.FIG. 21is a sectional view of the magnetic sensor inFIG. 20, as viewed from the direction indicated by the arrow of line XXI-XXI inFIG. 20.FIG. 22is a plan view of the magnetic sensor inFIG. 19, as viewed from the direction indicated by the arrow XXII inFIG. 19.

As shown inFIGS. 19 through 22, a magnetic sensor3according to the sixth preferred embodiment of the present invention includes a circuit substrate300, and two first magnets40and two second magnets50provided above the circuit substrate300. In the magnetic sensor3according to the sixth preferred embodiment of the present invention, on the circuit substrate300, two first conductors60and two second conductors70are provided. A first stress relaxer80is provided along a portion of each of the first conductors60. A second stress relaxer90is provided along a portion of each of the second conductors70. An insulating layer30is provided on the front layer of the circuit substrate300, and the two first conductors60, the two second conductors70, the first stress relaxers80, and the second stress relaxers90are located on the insulating layer30.

Each of the second conductors70includes a second base section71and a second narrow section72. The area of the exterior surface of the second narrow section72as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30, is smaller than that of the second base section71. In the second conductor70, the second base section71and the second narrow section72are provided side by side in the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30. In the sixth preferred embodiment, the second narrow section72of the second conductor70is positioned at the end portion of the second conductor70closer to the insulating layer30in the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30. That is, the second narrow section72of the second conductor70contacts the insulating layer30on the circuit substrate300.

As viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30, the exterior surface of each of the second base section71and the second narrow section72is a rectangle or substantially a rectangle having bending corners. The width of the exterior surface of the second narrow section72is smaller than that of the second base section71. The second base section71and the second narrow section72are provided coaxially or substantially coaxially. The second base section71is not restricted to the above-described shape and may have a circular or polygonal shape, for example. The second narrow section72is not restricted to the above-described shape and may have any shape if the area of the exterior surface as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30, is smaller than that of the second base section71.

The second narrow section72in the second conductor70provides a gap partially between the second base section71and the insulating layer30. In the sixth preferred embodiment, the gap is provided between the second base section71and the insulating layer30all around the outer peripheral portion of the second conductor70. The second stress relaxer90is provided in the gap.

The two second magnets50are located on the two second conductors70in a one-on-one relationship. The second magnets50cover the associated second conductors70, as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30.

With a view to decreasing the distance between each second magnet50and the circuit substrate300, the thickness of the second conductor70in the Z-axis direction, that is, the total thickness of the second base section71and the second narrow section72in the Z-axis direction, is preferably about 2.0 μm or smaller, for example. As the distance between the second magnet50and the circuit substrate300is smaller, the magnetic shielding function of the second magnet50is able to be provided more effectively. To form the second conductor70, patterning with a resist, for example, may be utilized.

In the sixth preferred embodiment, the second conductor is positioned on the insulating layer30and is preferably defined by, for example, a layer including titanium (Ti) and a layer including gold (Au) in this order from the bottom. The layer including titanium (Ti) is a contact layer. If the second magnet50is formed with electrolytic plating, the layer including gold (Au) defines and functions as an electrode reaction layer, that is, a seed layer. The second conductor70is not limited to the above-described features, and may include a layer made of at least one of iron (Fe), molybdenum (Mo), tantalum (Ta), platinum (Pt), and copper (Cu), which are materials defining and functioning as a plating seed layer. If the second magnet50is formed by a method other than plating, for example, by vapor-deposition, the second conductor70may be defined by a conductor including at least one of a metal or a resin.

Each of the second stress relaxers90is provided in a region T2which is surrounded by the exterior surface of the second narrow section72and also by the exterior surface of the second base section71, as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30. In the sixth preferred embodiment, the second stress relaxer90is sandwiched between the second base section71and the insulating layer30. The second stress relaxer90is located immediately under the outer peripheral portion of the second base section71. As viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30, the second stress relaxer90has a polygonal angular-ring shape in horizontal cross section. The second stress relaxer90is not limited to this shape. To form the second stress relaxer90, patterning with a resist, for example, may be utilized.

The second stress relaxer90is made of a material different from that of the second conductor70. As the material for the second stress relaxer90, at least one of a material having a lower adhesiveness, a material having a lower elastic modulus, and a material having a lower tensile strength than the material of the second conductor70may preferably be used.

If the second stress relaxer90includes a material having a low adhesiveness, a layer including a low-adhesiveness material is provided in contact with the insulating layer30. The material of the second stress relaxer90having a lower adhesiveness than that of the second conductor70is preferably, for example, gold (Au) or polyimide. For example, the second conductor70is preferably defined by a layer including titanium (Ti) on the insulating layer30and a layer including gold (Au) on the layer including titanium (Ti). The second stress relaxer90is defined only by a layer including gold (Au).

The material of the second stress relaxer90having an elastic modulus lower than that of the second conductor70is preferably a resin, for example, polyimide. The material of the second stress relaxer90having a tensile strength lower than that of the second conductor70is preferably, for example, SiO2or a low-density resin. To form the second stress relaxer90including SiO2, SOG (Spin-on Glass) may be applied onto the insulating layer30.

As shown inFIG. 22, four magnetoresistance elements electrically connected with each other by wiring to define a Wheatstone bridge circuit are provided on the circuit substrate300of the magnetic sensor3according to the sixth preferred embodiment of the present invention. The four magnetoresistance elements are defined by two pairs of first magnetoresistance elements and second magnetoresistance elements. More specifically, the magnetic sensor3includes first and second magnetoresistance elements320aand330aand first and second magnetoresistance elements320band330b. The first and second magnetoresistance elements320aand330adefine one pair. The first and second magnetoresistance elements320band330bdefine the other pair.

FIG. 23is a plan view showing a pattern of each of the first magnetoresistance elements of the magnetic sensor according to the sixth preferred embodiment of the present invention. As shown inFIGS. 22 and 23, each of the first magnetoresistance elements320aand320bhas a double-spiral pattern320, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The double-spiral pattern320includes two first patterns. The two first patterns are concentrically provided along the circumference of an imaginary circle and side by side one another in the radial direction of the imaginary circle and are connected with each other, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

The double-spiral pattern320includes spiral patterns321and322and an S-shaped pattern323. The spiral pattern321is one of the two first patterns, while the spiral pattern322is the other one of the two first patterns. The S-shaped pattern323connects the spiral patterns321and322at the central portion of the double-spiral pattern320. The S-shaped pattern323does not have any linearly extending portions and are defined only by curved portions.

The double-spiral pattern320includes a length-adjusting surplus section324at one end of the spiral pattern321and a length-adjusting surplus section325at one end of the spiral pattern322. The length-adjusting surplus sections324and325adjust the length of the double-spiral pattern320. The end of the spiral pattern321is curved and bends back at its end to define the length-adjusting surplus section324. The end of the spiral pattern322is curved and bends back at its end to define the length-adjusting surplus section325. The length-adjusting surplus section324provided at the spiral pattern321and the length-adjusting surplus section325provided at the spiral pattern322are located at the opposite sides in the radial direction of the double-spiral pattern320. Each of the length-adjusting surplus sections324and325does not have any linearly extending portions and is defined only by curved portions.

The double-spiral pattern320is connected at its length-adjusting surplus sections324and325to the conductive layer20forming the wiring. The connecting positions between the length-adjusting surplus sections324and325and the conductive layer20are able to be changed to adjust the electrical resistance of the first magnetoresistance elements320aand320b.

More specifically, at the connecting portion between the region R defining and functioning as the magnetoresistance elements and the region L defining and functioning as the wiring shown inFIG. 6, the conductive layer20extends toward the region R to increase the region L. Thus, the electrical resistance of the first magnetoresistance elements320aand320bis able to be reduced. Conversely, at the connecting portion between the region R defining and functioning as the magnetoresistance elements and the region L defining and functioning as the wiring, the conductive layer20retreats toward the region L to decrease the region L. Thus, the electrical resistance of the first magnetoresistance elements320aand320bis able to be increased.

The above-described adjustment of the electrical resistance of the first magnetoresistance elements320aand320bis performed by partially removing or adding the conductive layer20, and is thus preferably done before the insulating layer30is formed, for example.

As shown inFIG. 23, the double-spiral pattern320is substantially point-symmetrical with respect to the center of the double-spiral pattern320. That is, the double-spiral pattern320is rotationally symmetrical with respect to the center of the double-spiral pattern320by about 180°.

As shown inFIG. 22, the orientation of the circumferential direction of the double-spiral pattern320of the first magnetoresistance element320aand that of the first magnetoresistance element320bare different from each other so that the orientation of the S-shaped pattern323of the first magnetoresistance element320aand that of the first magnetoresistance element320bbecome different.

In the sixth preferred embodiment, the orientation of the circumferential direction of the double-spiral pattern320of the first magnetoresistance element320aand that of the first magnetoresistance element320bare different from each other by about 90°, for example, so that the orientation of the S-shaped pattern323of the first magnetoresistance element320aand that of the first magnetoresistance element320bbecome different from each other by about 90°, for example.

The double-spiral pattern320may be wound in the opposite direction, in which case, the central portion of the double-spiral pattern320is a reversed-S-shaped pattern defined only by curved portions. That is, one spiral pattern321and the other spiral pattern322are connected with each other by the reversed-S-shaped pattern.

FIG. 24is a plan view showing a pattern of each second magnetoresistance element of the magnetic sensor according to the sixth preferred embodiment of the present invention.FIG. 25is a plan view showing a second pattern included in the pattern of each second magnetoresistance element of the magnetic sensor according to the sixth preferred embodiment of the present invention. InFIG. 24, among three patterns330having the same or substantially the same shape included in each of the second magnetoresistance elements330aand330b, only one pattern330is shown.

As shown inFIGS. 22 and 24, the second magnetoresistance elements330aand330bare located farther outward than the outer peripheral edges of the first magnetoresistance elements320aand320b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In each of the second magnetoresistance elements330aand330b, the three patterns330having the same or substantially the same shape and each including eight second patterns370are connected in series with each other. Each second pattern370includes bending portions. In the second magnetoresistance element330a, the three patterns330having the same or substantially the same shape are connected with each other by wiring147. In the second magnetoresistance element330b, the three patterns330having the same or substantially the same shape are connected with each other by wiring151. The patterns330are formed thinner than the double-spiral patterns320. Accordingly, a predetermined electrical resistance in the second magnetoresistance elements330aand330bis able to be provided. As the electrical resistance of the second magnetoresistance elements330aand330bis higher, the current consumed in the magnetic sensor3is able to be reduced by a greater amount.

As shown inFIG. 24, the eight second patterns370are provided on an imaginary circle C3and are connected with each other. As shown inFIG. 25, each second pattern370has fourteen bending portions B1through B14and fifteen linearly extending portions L1through L15in a region from a starting portion370ato a terminating portion370bso that it bends back at the corners. The second pattern370has a bag shape using the starting portion370aand the terminating portion370bto form the mouth portion of the bag.

In the sixth preferred embodiment, the second pattern370bends at a right angle at each of the fourteen bending portions B1through B14. The second pattern370does not include any linearly extending portions having a length of about 10 μm or longer. That is, each of the fifteen linearly extending portions L1through L15preferably has a length shorter than about 10 μm, for example.

However, the second magnetoresistance elements330aand330bare not limited to the above-described pattern and may any pattern if they each include at least one second pattern defined by plural bending portions without having any linearly extending portion of a length of about 10 μm or longer.

With the above-described pattern, the magnetoresistance effect of the second magnetoresistance elements330aand330bis reduced to significantly decrease their resistance change rate. As a result, the resistance change rate of the second magnetoresistance elements330aand330bbecomes smaller than that of the first magnetoresistance elements320aand320b.

In the magnetic sensor3according to the sixth preferred embodiment, each of the first magnetoresistance elements320aand320bhas the double-spiral pattern320. The double-spiral pattern320is provided principally by winding substantially circular-arc curved portions. The shape of a circular arc approximates to a shape having an infinite number of corners of a polygon. Thus, the direction of a current flowing through the double-spiral pattern320covers about 360° in the horizontal direction. The first magnetoresistance elements320aand320bare thus able to detect an external magnetic field at about 360° in the horizontal direction.

In the magnetic sensor3according to the sixth preferred embodiment, the center of the double-spiral pattern320is the S-shaped pattern323defined only by curved portions, and the peripheral portions are the length-adjusting surplus sections324and325defined by curved portions. Accordingly, the first magnetoresistance elements320aand320bdo not have any linearly extending portions, thus reducing the anisotropic characteristics in detecting a magnetic field.

In the magnetic sensor3according to the sixth preferred embodiment, the orientation of the circumferential direction of the double-spiral pattern320of the first magnetoresistance element320aand that of the first magnetoresistance element320bare different from each other so that the orientation of the S-shaped pattern323of the first magnetoresistance element320aand that of the first magnetoresistance element320bbecome different, thus improving the isotropic characteristics in detecting a magnetic field.

In the magnetic sensor3according to the sixth preferred embodiment, each of the second magnetoresistance elements330aand330bincludes the following second patterns370. The second pattern370bends at a right angle at each of the fourteen bending portions B1through B14without having any linearly extending portion having a length of about 10 μm or longer to define a bag shape using the starting portion370aand the terminating portion370bto form the mouth portion of the bag.

Accordingly, the orientation of the current flowing through the second pattern370is able to be distributed in the horizontal direction, thus reducing the anisotropic characteristics of the magnetoresistance effect of each of the second magnetoresistance elements330aand330b. Thus, output variations of the magnetic sensor3when the external magnetic field is 0, which would be caused by the influence of residual magnetization, are able to be significantly reduced.

Additionally, the plural second patterns370are provided on the imaginary circle C3to distribute the orientation of the current flowing through the pattern330in the horizontal direction, thus reducing the anisotropic characteristics of the magnetoresistance effect of each of the second magnetoresistance elements330aand330b.

In the magnetic sensor3according to the sixth preferred embodiment, it is not necessary to three-dimensionally lay the wiring to connect the first magnetoresistance elements320aand320band the second magnetoresistance elements330aand330b. Thus, the circuit substrate300is able to be manufactured with a simple manufacturing process.

The pattern330is thinner than the double-spiral pattern320. Accordingly, the magnetoresistance effect of the second magnetoresistance elements330aand330bis able to be significantly reduced, to thus significantly decrease their resistance change rate.

Therefore, the potential difference generated between the nodes140and141may be increased when an external magnetic field is applied to the magnetic sensor3, thus improving the detection sensitivity of the magnetic sensor3. Additionally, since the electrical resistance of the second magnetoresistance elements330aand330bis high, there is only a relatively small decrease in the potential difference generated between the nodes140and141when an external magnetic field having a high magnetic field strength is applied to the magnetic sensor3, thus stabilizing the output characteristics of the magnetic sensor3.

In the magnetic sensor3according to the sixth preferred embodiment, the two first magnets40and the two second magnets50are provided on the insulating layer30. The thickness of each of the first magnets40and the second magnets50is preferably about 10 μm or greater, for example, and more preferably, for example, about 20 μm to about 150 μm. The thicknesses of the first and second magnets40and50may be different from each other. However, if the two first magnets40and the two second magnets50have the same or substantially the same thickness, they may be formed in the same step, thus facilitating the formation of the two first magnets40and the two second magnets50.

As shown inFIG. 22, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets40have an externally circular or substantially circular shape and are located in the regions farther inward than the outer peripheral edges of the first magnetoresistance elements320aand320b. In the sixth preferred embodiment, the first magnets40are located concentrically with the outer peripheral edges of the first magnetoresistance elements320aand320b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In the sixth preferred embodiment, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets40cover only the central portions of the first magnetoresistance elements320aand320bamong the first magnetoresistance elements320aand320band the second magnetoresistance elements330aand330b. The first magnets40are thus surrounded by the outer peripheral portions of the first magnetoresistance elements320aand320b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the second magnets50do not cover the first magnetoresistance elements320aand320b, but cover the second magnetoresistance elements330aand330b. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, each of the second magnetoresistance elements330aand330bis preferably positioned, for example, in the area from the center of the second magnet50to the position separated inward from the outer peripheral edge of the second magnet50by about 7 μm. The second magnets50are preferably made of a magnetic material having a high permeability and a high saturation magnetic flux density, for example, electromagnetic steel, mild steel, silicon steel, permalloy, supermalloy, a nickel alloy, an iron alloy, or ferrite. These magnetic materials preferably have low magnetic coercivity, for example.

The magnetic sensor3of the sixth preferred embodiment of the present invention is able to significantly improve the detection sensitivity of the first magnetoresistance elements320aand320bfor a vertical magnetic field by using the first magnets while reducing a change in the resistance of the second magnetoresistance elements330aand330bin response to a vertical magnetic field.

The magnetic sensor3of the sixth preferred embodiment of the present invention is able to also significantly improve the detection sensitivity of the first magnetoresistance elements320aand320bfor a horizontal magnetic field by using the first magnets while reducing a change in the resistance of the second magnetoresistance elements330aand330bin response to a horizontal magnetic field by using the second magnets50.

The significant improvement in detection sensitivity of the first magnetoresistance elements320aand320bfor a horizontal magnetic field by the first magnets40is described below. The strength of a horizontal magnetic field applied to the central portion of each of the first magnetoresistance elements320aand320bis low because the central portion thereof is covered by the first magnet40. Yet, a horizontal-direction magnetic field output from the first magnet40at a high magnetic field strength is applied to the outer peripheral portion of each of the first magnetoresistance elements320aand320b, which has a longer circumference and has a higher resistance ratio to that of the entire pattern than the central portion. As a whole, the strength of the horizontal magnetic field applied from the first magnets40to the first magnetoresistance elements320aand320bbecomes high.

The magnetic sensor3according to the sixth preferred embodiment is also able to detect a vertical magnetic field and a horizontal magnetic field with high sensitivity. In the magnetic sensor3according to the sixth preferred embodiment of the present invention, each of the first magnetoresistance elements320aand320bincludes concentrically provided multiple first patterns, thus improving the isotropic characteristics in detecting a horizontal magnetic field.

In the present preferred embodiment, the second magnetoresistance elements330aand330bare magnetically shielded by the second magnets50and hardly detect vertical magnetic fields and horizontal magnetic fields. The resistance change rate of the second magnetoresistance elements330aand330bmay not necessarily be smaller than that of the first magnetoresistance elements320aand320b.

In the magnetic sensor3according to the sixth preferred embodiment of the present invention, the second conductors70and the second stress relaxers90are provided between the second magnets50and the circuit substrate300. Each second conductor includes the second base section71and the second narrow section72, and the second narrow section72of the second conductor70contacts the circuit substrate300. The second stress relaxer90is provided in a gap between the second base section71and the insulating layer30. The second stress relaxer90is a component or element including a material different from the second conductor70. The second stress relaxer90includes at least one of a material having a lower adhesiveness, a material having a lower elastic modulus, and a material having a lower tensile strength than the material of the second conductor70.

Accordingly the contact area between the second conductor70and the circuit substrate300is able to be significantly increased, thus decreasing a stress applied from the second magnet50to each of the second magnetoresistance elements330aand330bvia the second conductor70. Additionally, the second stress relaxer90is provided immediately under the outer peripheral portion of the second base section71. The second stress relaxer90is able to thus relax a stress caused by a distortion produced at the outer peripheral portion of the second magnet50to be applied to the circuit substrate300.

More specifically, if the second stress relaxer90is made of a material having a lower adhesiveness than the material of the second conductor70, when the second stress relaxer90is subjected to a stress caused by a distortion produced at the outer peripheral portion of the second magnet50, it separates from a component or element adjacent to the second stress relaxer90. Accordingly, transmission of the stress to the adjacent component or element via the second stress relaxer90is significantly reduced or prevented.

If the second stress relaxer90is made of a material having a lower elastic modulus than the material of the second conductor70, when the second stress relaxer90is subjected to a stress caused by a distortion produced at the outer peripheral portion of the second magnet50, it elastically deforms to absorb the stress. Accordingly, transmission of the stress to a component or element adjacent to the second stress relaxer90via the second stress relaxer90is significantly reduced or prevented.

If the second stress relaxer90is made of a material having a lower tensile strength than the material of the second conductor70, when the second stress relaxer90is subjected to a stress caused by a distortion produced at the outer peripheral portion of the second magnet50, it cracks and separates from a component or element adjacent to the second stress relaxer90. Accordingly, transmission of the stress to the adjacent component or element via the second stress relaxer90is significantly reduced or prevented.

Thus, the second stress relaxer90is able to relax a stress caused by a distortion produced at the outer peripheral portion of the second magnet50to be applied from the second magnet50to each of the second magnetoresistance elements130aand130bvia the second conductor70. Accordingly, a decrease in the output accuracy of the magnetic sensor3is able to be regulated. It is also less likely that the insulating layer30cracks due to a stress applied from the second magnet50to the insulating layer30via the second conductor70. Thus, the reliability of the magnetic sensor3is able to be maintained.

In the sixth preferred embodiment, a gap is provided between the second base section71and the insulating layer30all around the outer peripheral portion of the second conductor70. Thus, the application of a stress caused by a distortion produced at the outer peripheral portion of the second magnet50to the circuit substrate300via the second conductor70is able to be significantly reduced.

The magnetic sensor3according to the sixth preferred embodiment of the present invention also provides high isotropic characteristics in detecting a horizontal magnetic field and is also able to detect a weak vertical magnetic field by using magnetoresistance elements. The magnetic sensor3is also able to regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements.

Features, components, and elements of the first conductor60aaccording to the second preferred embodiment may be applied to the second conductor70. Accordingly, the second narrow section of the second conductor is located at the end portion of the second conductor closer to the second magnet50in the direction perpendicular or substantially perpendicular to the insulating layer30.

The second stress relaxer90is provided in a region which is surrounded by the exterior surface of the second narrow section72and also by the exterior surface of the second base section71of the second conductor, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The second stress relaxer90is sandwiched between the second base section71and the second magnet50. The second stress relaxer90is located immediately under the outer peripheral portion of the second magnet50.

Alternatively, the features, components, and elements of the first conductor60baccording to the third preferred embodiment may be applied to the second conductor70. Accordingly, the second base section71of the second conductor70is located at the end portion of the second conductor70closer to the insulating layer and that closer to the second magnet50in the direction perpendicular or substantially perpendicular to the insulating layer30. The second narrow section72of the second conductor is sandwiched between the second base sections71of the second conductor in the direction perpendicular or substantially perpendicular to the insulating layer30.

The second stress relaxer90is provided in a region which is surrounded by the exterior surface of the second narrow section72and also by the exterior surface of the second base section71of the second conductor, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The second stress relaxer90is sandwiched between the second base sections71. The second stress relaxer90is located immediately under the outer peripheral portion of the second base section71positioned at the end portion of the second conductor closer to the second magnet50.

Alternatively, the features, components, and elements of the first magnet40aaccording to the fourth preferred embodiment may be applied to the second magnet50. Accordingly, the magnetic sensor3does not include the second conductor70. The second magnet includes a second base section and a second narrow section. The area of the exterior surface of the second narrow section is smaller than that of the second base section, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. In the second magnet, the second base section and the second narrow section are provided side by side in the direction perpendicular or substantially perpendicular to the insulating layer30. The second narrow section of the second magnet is positioned at the end portion of the second magnet closer to the insulating layer30in the direction perpendicular or substantially perpendicular to the insulating layer30.

The second stress relaxer90is provided in a region which is surrounded by the exterior surface of the second narrow section and also by the exterior surface of the second base section of the second magnet, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The second stress relaxer90is sandwiched between the second base section of the second magnet and the insulating layer30. The second stress relaxer90is located immediately under the outer peripheral portion of the second base section of the second magnet. The second stress relaxer90is made of a material different from the second magnet. The second stress relaxer90is preferably made of, for example, at least one of a material having a lower adhesiveness, a material having a lower elastic modulus, and a material having a lower tensile strength than the material of the second magnet.

Seventh Preferred Embodiment

A magnetic sensor according to a seventh preferred embodiment of the present invention will be described below with reference to the drawings. The magnetic sensor according to the seventh preferred embodiment of the present invention is different from the magnetic sensor3of the sixth preferred embodiment of the present invention mainly in the patterns of first and second magnetoresistance elements. An explanation of elements similar to those of the magnetic sensor3of the sixth preferred embodiment of the present invention will not be repeated.

FIG. 26is a perspective view showing the magnetic sensor according to the seventh preferred embodiment of the present invention.FIG. 27is a plan view of the magnetic sensor inFIG. 26, as viewed from the direction indicated by the arrow XXVII inFIG. 26. As shown inFIGS. 26 and 27, a magnetic sensor4according to the seventh preferred embodiment of the present invention includes a circuit substrate400and two first magnets40and two second magnets50provided above the circuit substrate400. In the magnetic sensor4according to the seventh preferred embodiment of the present invention, on the circuit substrate400, two first conductors60and two second conductors70are provided. A first stress relaxer80is provided along a portion of each of the first conductors60. A second stress relaxer90is provided along a portion of each of the second conductors70. An insulating layer30is provided on the front layer of the circuit substrate400, and the two first conductors60, the two second conductors70, the first stress relaxers80, and the second stress relaxers90are located on the insulating layer30. The first magnets40cover the associated first conductors60, as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30. The second magnets50cover the associated second conductors70, as viewed from the Z-axis direction, which is perpendicular or substantially perpendicular to the insulating layer30.

Four magnetoresistance elements electrically connected with each other by wiring to define a Wheatstone bridge circuit are provided on the circuit substrate400of the magnetic sensor4according to the seventh preferred embodiment of the present invention. The four magnetoresistance elements are defined by two pairs of first magnetoresistance elements and second magnetoresistance elements. More specifically, the magnetic sensor4includes first and second magnetoresistance elements420aand430aand first and second magnetoresistance elements420band430b.

Each of the first magnetoresistance elements420aand420bhas a double-spiral pattern, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The double-spiral pattern includes two first patterns. The two first patterns are concentrically provided along the circumference of an imaginary circle and side by side one another in the radial direction of the imaginary circle and are connected with each other, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

The double-spiral pattern includes two spiral patterns, which are the two first patterns, and an S-shaped pattern. The S-shaped pattern connects the two spiral patterns at the central portion of the double-spiral pattern. The S-shaped pattern does not have any linearly extending portions and are defined only by curved portions.

The orientation of the circumferential direction of the double-spiral pattern of the first magnetoresistance element420aand that of the first magnetoresistance element420bare different from each other so that the orientation of the S-shaped pattern of the first magnetoresistance element420aand that of the first magnetoresistance element420bbecome different.

In the seventh preferred embodiment, the orientation of the circumferential direction of the double-spiral pattern of the first magnetoresistance element420aand that of the first magnetoresistance element420bare different from each other by about 90° so that the orientation of the S-shaped pattern of the first magnetoresistance element420aand that of the first magnetoresistance element420bbecome different from each other by about 90°, for example.

The double-spiral pattern may be wound in the opposite direction, in which case, the central portion of the double-spiral pattern is a reversed-S-shaped pattern defined only by curved portions. That is, one spiral pattern and the other spiral pattern are connected with each other by the reversed-S-shaped pattern.

As shown inFIG. 27, the second magnetoresistance elements430aand430bare located farther outward than the outer peripheral edges of the first magnetoresistance elements420aand420b, respectively, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The second magnetoresistance elements430aand430beach have a meandering pattern, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The meandering patterns of the second magnetoresistance elements430aand430bpreferably have the same or substantially the same thickness as the double-spiral patterns of the first magnetoresistance elements420aand420b. However, these meandering patterns may be thinner than the double-spiral patterns of the first magnetoresistance elements420aand420b.

As shown inFIG. 27, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets40have an externally circular shape and are located in the regions farther inward than the outer peripheral edges of the first magnetoresistance elements420aand420b. In the seventh preferred embodiment, the first magnets40are located concentrically with the outer peripheral edges of the first magnetoresistance elements420aand420b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In the seventh preferred embodiment, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets40cover only the central portions of the first magnetoresistance elements420aand420bamong the first magnetoresistance elements420aand420band the second magnetoresistance elements430aand430b. The first magnets40are thus surrounded by the outer peripheral portions of the first magnetoresistance elements420aand420b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the second magnets50do not cover the first magnetoresistance elements420aand420b, but cover the second magnetoresistance elements430aand430b.

The magnetic sensor4of the seventh preferred embodiment of the present invention is able to significantly improve the detection sensitivity of the first magnetoresistance elements420aand420bfor a vertical magnetic field by using the first magnets40while reducing a change in the resistance of the second magnetoresistance elements430aand430bin response to a vertical magnetic field.

The magnetic sensor4of the seventh preferred embodiment of the present invention is also able to significantly improve the detection sensitivity of the first magnetoresistance elements420aand420bfor a horizontal magnetic field by using the first magnets40while reducing a change in the resistance of the second magnetoresistance elements430aand430bin response to a horizontal magnetic field by using the second magnets50.

The magnetic sensor4according to the seventh preferred embodiment is also able to detect a vertical magnetic field and a horizontal magnetic field with high sensitivity. In the magnetic sensor4according to the seventh preferred embodiment of the present invention, each of the first magnetoresistance elements420aand420bincludes concentrically provided multiple first patterns, thus improving the isotropic characteristics in detecting a horizontal magnetic field.

In the present preferred embodiment, the second magnetoresistance elements430aand430bare magnetically shielded by the second magnets50and hardly detect vertical magnetic fields and horizontal magnetic fields. The resistance change rate of the second magnetoresistance elements430aand430bmay not necessarily be smaller than that of the first magnetoresistance elements420aand420b.

The magnetic sensor4according to the seventh preferred embodiment of the present invention also provides high isotropic characteristics in detecting a horizontal magnetic field and is also able to detect a weak vertical magnetic field by using magnetoresistance elements. The magnetic sensor4is also able to regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements.

Eighth Preferred Embodiment

A magnetic sensor according to an eighth preferred embodiment of the present invention will be described below with reference to the drawings. The magnetic sensor according to the eighth preferred embodiment of the present invention is different from the magnetic sensor1of the first preferred embodiment of the present invention mainly in the patterns of the first and second magnetoresistance elements and the first magnets. An explanation of elements similar to those of the magnetic sensor1of the first preferred embodiment of the present invention will not be repeated.

FIG. 28is a plan view showing the magnetic sensor according to the eighth preferred embodiment of the present invention.FIG. 29is a plan view showing a pattern of a first magnetoresistance element of the magnetic sensor according to the eighth preferred embodiment of the present invention.FIG. 30is a plan view showing a pattern of a second magnetoresistance element of the magnetic sensor according to the eighth preferred embodiment of the present invention.

As shown inFIG. 28, a magnetic sensor5of the eighth preferred embodiment of the present invention includes a circuit substrate500and two first magnets45provided above the circuit substrate500. In the magnetic sensor5according to the eighth preferred embodiment of the present invention, on the circuit substrate500, two first conductors are provided. A first stress relaxer is provided along a portion of each of first conductors60. The first magnets45cover the associated first conductors, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

As shown inFIGS. 28 and 29, a pattern of each of first magnetoresistance elements520aand520bof the magnetic sensor5of the eighth preferred embodiment of the present invention includes four first patterns. The four first patterns are provided along the circumference of an imaginary circle C5and side by side one another in the radial direction of the imaginary circle C5and are connected with each other, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The four first patterns are located along an imaginary C-shaped feature C51, which is opened at a portion where wiring146,148,150, and152is positioned, on the circumference of the imaginary circle C5. The four first patterns are C-shaped patterns521concentrically provided along the imaginary C-shaped feature C51and side by side one another in the radial direction of the imaginary circle C5.

The four C-shaped patterns521are connected with each other alternately at one end and at the other end starting from inward. The C-shaped patterns521connected with each other at one end are connected with each other by a linear pattern522extending in the radial direction of the imaginary circle C5. The C-shaped patterns521connected with each other at the other end are connected with each other by a linear pattern523extending in the radial direction of the imaginary circle C5.

The pattern520of each of the first magnetoresistance elements520aand520bincludes two linear patterns522and one linear pattern523. Accordingly, the four C-shaped patterns521are connected in series with each other.

The outer peripheral edge of the C-shaped pattern521positioned at the outermost side is the outer peripheral edge of each of the first magnetoresistance elements520aand520b. The inner peripheral edge of the C-shaped pattern521positioned at the innermost side is the inner peripheral edge of each of the first magnetoresistance elements520aand520b.

As shown inFIG. 28, the orientation of the circumferential direction of the first magnetoresistance element520aand that of the first magnetoresistance element520bare different from each other so that the orientations of the imaginary C-shaped features C51become different. That is, the orientation of the circumferential direction of the pattern520of the first magnetoresistance element520aand that of the first magnetoresistance element520bare different from each other so that the orientation of the C-shaped patterns521of the first magnetoresistance element520aand that of the first magnetoresistance element520bbecome different.

In the eighth preferred embodiment, the orientation of the circumferential direction of the pattern520of the first magnetoresistance element520aand that of the first magnetoresistance element520bdiffer from each other by about 90°, for example, so that the orientation of the C-shaped patterns521of the first magnetoresistance element520aand that of the first magnetoresistance element520bbecome different from each other by about 90°.

As shown inFIGS. 28 and 30, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, a second magnetoresistance element530ais positioned at the central side of the imaginary circle C5and is surrounded by the first magnetoresistance element520a, while a second magnetoresistance element530bis positioned at the central side of the imaginary circle C5and is surrounded by the first magnetoresistance element520b. That is, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the second magnetoresistance element530ais located farther inward than the inner peripheral edge of the first magnetoresistance element520a, while the second magnetoresistance element530bis located farther inward than the inner peripheral edge of the first magnetoresistance element520b.

The second magnetoresistance element530ais connected to the wiring146and148provided from the central side of the imaginary circle C5to the outer side of the imaginary circle C5. The second magnetoresistance element530bis connected to the wiring150and152provided from the central side of the imaginary circle C5to the outer side of the imaginary circle C5.

Each of the second magnetoresistance elements530aand530bhas a double-spiral pattern530, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The double-spiral pattern530includes spiral patterns531and532and a reversed-S-shaped pattern533. The spiral pattern531is one of two second patterns, while the spiral pattern532is the other one of the two second patterns. The reversed-S-shaped pattern533connects the spiral patterns531and532at the central portion of the double-spiral pattern530. The reversed-S-shaped pattern533is defined by multiple linearly extending portions having a length shorter than about 10 μm.

The double-spiral pattern530has the same or substantially the same thickness as the pattern520. The spiral patterns531and532accordingly have the same or substantially the same thickness as each of the four C-shaped patterns521. However, the double-spiral pattern530may be thinner than the pattern520.

As shown inFIG. 30, the double-spiral pattern530is substantially point-symmetrical with respect to the center of the imaginary circle C5. That is, the double-spiral pattern530is rotationally symmetrical with respect to the center of the imaginary circle C5by about 180°.

As shown inFIG. 28, the orientation of the circumferential direction of the double-spiral pattern530of the second magnetoresistance element530aand that of the second magnetoresistance element530bare different from each other so that the orientation of the reversed-S-shaped pattern533of the second magnetoresistance element530aand that of the second magnetoresistance element530bbecome different.

In the eighth preferred embodiment, the orientation of the circumferential direction of the double-spiral pattern530of the second magnetoresistance element530aand that of the second magnetoresistance element530bare different from each other by about 90°, for example, so that the orientation of the reversed-S-shaped pattern533of the second magnetoresistance element530aand that of the second magnetoresistance element530bbecome different from each other by about 90°, for example.

In the magnetic sensor5according to the eighth preferred embodiment, each of the first magnetoresistance elements520aand520bhas the C-shaped patterns521. The C-shaped patterns521are each defined by almost seven sides among the eight sides of a substantially regular octagon. Accordingly, the first magnetoresistance elements520aand520bare defined by most of the sides of a polygon, thus reducing the anisotropic characteristics in detecting a magnetic field.

Additionally, in the magnetic sensor5according to the eighth preferred embodiment, the orientation of the circumferential direction of the pattern520of the first magnetoresistance element520aand that of the first magnetoresistance element520bare different from each other so that the orientation of the C-shaped patterns521of the first magnetoresistance element520aand that of the first magnetoresistance element520bbecome different, thus improving the isotropic characteristics in detecting a magnetic field.

In the magnetic sensor5according to the eighth preferred embodiment, each of the second magnetoresistance elements530aand530bhas the double-spiral pattern530. The double-spiral pattern530is formed principally by winding the sides forming a substantially regular octagon.

In the magnetic sensor5according to the eighth preferred embodiment, the orientation of the circumferential direction of the double-spiral pattern530of the second magnetoresistance element530aand that of the second magnetoresistance element530bare different from each other so that the orientation of the reversed-S-shaped pattern533of the second magnetoresistance element530aand that of the second magnetoresistance element530bbecome different, thus improving the isotropic characteristics of the magnetoresistance effect.

In the magnetic sensor5according to the eighth preferred embodiment, the second magnetoresistance elements530aand530bare provided inward of the first magnetoresistance elements520aand520b, respectively, and thus the size of the magnetic sensor5is able to be significantly reduced.

Additionally, in the magnetic sensor5, it is not necessary to three-dimensionally lay the wiring to connect the first magnetoresistance elements520aand520band the second magnetoresistance elements530aand530b. Thus, the circuit substrate500is able to be manufactured with a simple manufacturing process.

In the magnetic sensor5according to the eighth preferred embodiment, the two first magnets45are provided above the insulating layer30. As shown inFIG. 28, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets45each have an externally regular-octagonal shape and are located in the regions farther inward than the outer peripheral edges of the first magnetoresistance elements520aand520b. The regions farther inward than the outer peripheral edges of the first magnetoresistance elements520aand520bare regions surrounded by the outer peripheral edges of the first magnetoresistance elements520aand520bwhen both ends of the outer peripheral edge of each of the first magnetoresistance elements520aand520bare connected with each other by an imaginary line, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. Preferably, for example, at least about one half, and more preferably, for example, at least about ⅔, of the region farther inward than the outer peripheral edge of each of the first magnetoresistance elements520aand520boverlaps the corresponding first magnet45, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the first magnets45are located in the regions farther inward than the inner peripheral edges of the first magnetoresistance elements520aand520b. The first magnets45may be each located in a region including the inner peripheral edge of the corresponding one of the first magnetoresistance elements520aand520band the area inward of the inner peripheral edge, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. The regions farther inward than the inner peripheral edges of the first magnetoresistance elements520aand520bare regions surrounded by the inner peripheral edges of the first magnetoresistance elements520aand520bwhen both ends of the inner peripheral edge of each of the first magnetoresistance elements520aand520bare connected with each other by an imaginary line, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. Preferably, for example, at least about one half, and more preferably, for example, at least about ⅔, of the region farther inward than the inner peripheral edge of each of the first magnetoresistance elements520aand520boverlaps the corresponding first magnet45, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In the eighth preferred embodiment, the first magnets45are positioned concentrically with the outer peripheral edges of the first magnetoresistance elements520aand520b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In the eighth preferred embodiment, the first magnets45do not cover the first magnetoresistance elements520aand520b, but cover the second magnetoresistance elements530aand530b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. As viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, for example, at least about ½ of the entirety of the outer peripheral portion of each of the first magnet45is preferably surrounded by the corresponding first magnetoresistance elements520aand520b.

The magnetic sensor5according to the eighth preferred embodiment is also able to detect a vertical magnetic field and a horizontal magnetic field with high sensitivity. In the magnetic sensor5according to the eighth preferred embodiment of the present invention, each of the first magnetoresistance elements520aand520bincludes multiple first patterns formed in a polygonal shape, thus improving the isotropic characteristics in detecting a horizontal magnetic field.

Although in the eighth preferred embodiment the first magnetoresistance elements520aand520b, the second magnetoresistance elements530aand530b, and the first magnets45have concentric regular-octagonal shapes, they may be have any concentric polygonal shape. With more corners of this polygonal shape, the isotropic characteristics of the first magnetoresistance elements520aand520bin detecting a horizontal magnetic field is able to be improved.

In the eighth preferred embodiment, the second magnetoresistance elements530aand530bare magnetically shielded by the first magnets45and hardly detect vertical magnetic fields and horizontal magnetic fields. The resistance change rate of the second magnetoresistance elements530aand530bmay not necessarily be smaller than that of the first magnetoresistance elements520aand520b.

The magnetic sensor5according to the eighth preferred embodiment of the present invention also provides high isotropic characteristics in detecting a horizontal magnetic field and is also able to detect a weak vertical magnetic field by using magnetoresistance elements. The magnetic sensor5is also able to regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements.

Ninth Preferred Embodiment

A magnetic sensor according to a ninth preferred embodiment of the present invention will be described below with reference to the drawings. The magnetic sensor according to the ninth preferred embodiment of the present invention is different from the magnetic sensor1cof the fourth preferred embodiment of the present invention mainly in the patterns of the first and second magnetoresistance elements. An explanation of elements similar to those of the magnetic sensor1cof the fourth preferred embodiment of the present invention will not be repeated.

FIG. 31is a plan view of the magnetic sensor according to the ninth preferred embodiment of the present invention.FIG. 32is a plan view showing a pattern of a first magnetoresistance element and that of a second magnetoresistance element of the magnetic sensor according to the ninth preferred embodiment of the present invention. InFIGS. 31 and 32, the inner peripheral edges and the outer peripheral edges of first magnets are indicated by the dotted lines.

As shown inFIG. 31, a magnetic sensor6according to the ninth preferred embodiment of the present invention includes a circuit substrate600and two first magnets40aprovided above the circuit substrate600. In the magnetic sensor6according to the ninth preferred embodiment of the present invention, a gap is provided between a first base section41of the first magnet40aand the circuit substrate600all around the outer peripheral portion of the first magnet40a. A first stress relaxer is provided in the entirety of this gap.

As shown inFIGS. 31 and 32, a pattern620of each of first magnetoresistance elements620aand620bof the magnetic sensor6according to the ninth preferred embodiment of the present invention includes one first pattern. The first pattern is a C-shaped pattern621located along an imaginary C-shaped feature C61, which is opened at a portion where wiring146,148,150, and152is positioned, on the circumference of an imaginary circle C6, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. As the distance between the inner peripheral edge of each of the first magnetoresistance elements620aand620band the outer peripheral edge of the first base section41of the first magnet40a, a sufficiently large distance is provided so that the first magnetoresistance elements620aand620bdo not overlap the first magnets40aeven if the positions of the first magnets40awhen being formed by plating are varied.

As shown inFIG. 31, the orientation of the circumferential direction of the first magnetoresistance element620aand that of the first magnetoresistance element620bare different from each other so that the orientations of the imaginary C-shaped features C61become different. That is, the orientation of the circumferential direction of the pattern620of the first magnetoresistance element620aand that of the first magnetoresistance element620bare different from each other so that the orientation of the C-shaped pattern621of the first magnetoresistance element620aand that of the first magnetoresistance element620bbecome different.

In the ninth preferred embodiment, the orientation of the circumferential direction of the pattern620of the first magnetoresistance element620aand that of the first magnetoresistance element620bdiffer from each other by about 135°, for example, so that the orientation of the C-shaped pattern621of the first magnetoresistance element620aand that of the first magnetoresistance element620bbecome different from each other by about 135°, for example.

As shown inFIG. 31, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, a second magnetoresistance element630ais positioned at the central side of the imaginary circle C6and is surrounded by the first magnetoresistance element620a, while a second magnetoresistance element630bis positioned at the central side of the imaginary circle C6and is surrounded by the first magnetoresistance element620b. That is, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the second magnetoresistance element630ais located farther inward than the inner peripheral edge of the first magnetoresistance element620a, while the second magnetoresistance element630bis located farther inward than the inner peripheral edge of the first magnetoresistance element620b.

Each of the second magnetoresistance elements630aand630bhas a pattern630. The pattern630includes two arc patterns631, which are second patterns, provided along the circumference of the imaginary circle C6line-symmetrically to each other and side by side one another in the radial direction of the imaginary circle C6. The two arc patterns631are connected with each other at one end by a semi-circular pattern632and at the other end by a semi-circular pattern633. In the second magnetoresistance element630a, the arc pattern631positioned on the outermost side from the center of the imaginary circle C6is connected to the wiring146and148by a linearly extending portion634having a length shorter than about 10 μm, for example. In the second magnetoresistance element630b, the arc pattern631positioned on the outermost side from the center of the imaginary circle C6is connected to the wiring150and152by a linearly extending portion634having a length shorter than about 10 μm, for example.

In the second magnetoresistance element630aand630b, as the distance between the inner peripheral edge of the arc pattern631positioned closer to the center of the imaginary circle C6and the outer peripheral edge of the first narrow section42of the first magnet40a, a sufficiently large distance is provided so that the second magnetoresistance elements630aand630bdo not overlap the first narrow sections42of the first magnets40aeven if the positions of the first magnets40awhen being formed by plating are varied.

The patterns630of the second magnetoresistance elements630aand630bhave the same or substantially the same thickness as the patterns620of the first magnetoresistance elements620aand620b. However, the patterns630may be thinner than the patterns620.

In the magnetic sensor6according to the ninth preferred embodiment, each of the second magnetoresistance elements630aand630bhas the arc patterns631. The arc patterns631are formed of arcs. The two adjacent arc patterns631are connected with each other by the semi-circular patterns632and633. Each of the second magnetoresistance elements630aand630bincludes the linearly extending portion634merely having a length shorter than about 10 μm, for example. Thus, the anisotropic characteristics in detecting a magnetic field are able to be significantly reduced.

The orientation of the circumferential direction of the pattern630of the second magnetoresistance element630aand that of the second magnetoresistance element630bare different from each other. In the ninth preferred embodiment, the orientation of the circumferential direction of the pattern630of the second magnetoresistance element630aand that of the second magnetoresistance element630bare different from each other by about 135°. Accordingly, the anisotropic characteristics of the magnetoresistance effect of the second magnetoresistance element630aand that of the second magnetoresistance element630bare able to be offset from each other and be reduced to a smaller level.

In the magnetic sensor6according to the ninth preferred embodiment, too, the second magnetoresistance elements630aand630bare provided inward of the first magnetoresistance elements620aand620b, respectively, and thus the size of the magnetic sensor6is able to be significantly reduced. Additionally, in the magnetic sensor6, too, it is not necessary to three-dimensionally lay the wiring to connect the first magnetoresistance elements620aand620band the second magnetoresistance elements630aand630b. Thus, the circuit substrate600is able to be manufactured with a simple manufacturing process.

As shown inFIG. 31, the first magnets40ado not cover the first magnetoresistance elements620aand620b, but cover the second magnetoresistance elements630aand630b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

The magnetic sensor6according to the ninth preferred embodiment is also able to detect a vertical magnetic field and a horizontal magnetic field with high sensitivity. In the magnetic sensor6according to the ninth preferred embodiment of the present invention, each of the first magnetoresistance elements620aand620bincludes the first pattern provided along the circumference thereof, thus improving the isotropic characteristics in detecting a horizontal magnetic field.

In this preferred embodiment, the second magnetoresistance elements630aand630bare magnetically shielded by the first magnets40aand hardly detect vertical magnetic fields and horizontal magnetic fields. The resistance change rate of the second magnetoresistance elements630aand630bmay not necessarily be smaller than that of the first magnetoresistance elements620aand620b.

The magnetic sensor6according to the ninth preferred embodiment of the present invention also provides high isotropic characteristics in detecting a horizontal magnetic field and is also able to detect a weak vertical magnetic field by using magnetoresistance elements. The magnetic sensor6is also able to regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements.

In the magnetic sensor6according to the ninth preferred embodiment, as the distance between the inner peripheral edge of each of the first magnetoresistance elements620aand620band the outer peripheral edge of the first base section41of the first magnet40a, a sufficiently large distance is provided so that the first magnetoresistance elements620aand620bdo not overlap the first magnets40aeven if the positions of the first magnets40awhen being formed by plating are varied. Thus, a stress is less likely to be applied from the first magnets40ato the first magnetoresistance elements620aand620bvia the corresponding stress relaxers.

In the magnetic sensor6according to the ninth preferred embodiment, as the distance between the inner peripheral edge of the arc pattern631positioned closer to the center of the imaginary circle C6and the outer peripheral edge of the first narrow section42of the first magnet40a, a sufficiently large distance is provided so that the second magnetoresistance elements630aand630bdo not overlap the first narrow sections42of the first magnets40aeven if the positions of the first magnets40awhen being formed by plating are varied. Thus, a stress is less likely to be applied from the first narrow sections42of the first magnets40ato the second magnetoresistance elements630aand630b.

Tenth Preferred Embodiment

A magnetic sensor according to a tenth preferred embodiment of the present invention will be described below with reference to the drawings. The magnetic sensor according to the tenth preferred embodiment of the present invention is different from the magnetic sensor6of the ninth preferred embodiment of the present invention mainly in the pattern of the first magnetoresistance elements and the first magnets. An explanation of elements similar to those of the magnetic sensor6of the ninth preferred embodiment of the present invention will not be repeated.

FIG. 33is a plan view of the magnetic sensor according to the tenth preferred embodiment of the present invention. FIG.34is a plan view showing a pattern of a first magnetoresistance element and that of a second magnetoresistance element of the magnetic sensor according to the tenth preferred embodiment of the present invention. InFIGS. 33 and 34, the inner peripheral edges and the outer peripheral edges of the first magnets are indicated by the dotted lines.

As shown inFIG. 33, a magnetic sensor7according to the tenth preferred embodiment of the present invention includes a circuit substrate700and two first magnets40bprovided above the circuit substrate700. Each first magnet40bincludes a first base section41band a first narrow section42. The area of the exterior surface of the first narrow section42as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30is smaller than that of the first base section41b. The first base section41bas viewed from the direction perpendicular or substantially perpendicular to the insulating layer30preferably has an externally octagonal shape, for example. In the magnetic sensor7according to the tenth preferred embodiment of the present invention, a gap is provided between the first base section41bof the first magnet40band the circuit substrate700all around the outer peripheral portion of the first magnet40b. A first stress relaxer is provided in the entirety or substantially the entirety of the gap.

As shown inFIGS. 33 and 34, a pattern720of each of first magnetoresistance elements720aand720bof the magnetic sensor7according to the tenth preferred embodiment of the present invention includes one first pattern. The first pattern is a C-shaped pattern721located along an imaginary C-shaped feature C61, which is opened at a portion where wiring146,148,150, and152is positioned, on the circumference of an imaginary circle C6, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. As the distance between the inner peripheral edge of each of the first magnetoresistance elements720aand720band the outer peripheral edge of the first base section41bof the first magnet40b, a sufficiently large distance is provided so that the first magnetoresistance elements720aand720bdo not overlap the first magnets40beven if the positions of the first magnets40bwhen being formed by plating are varied.

As shown inFIG. 33, the orientation of the circumferential direction of the first magnetoresistance element720aand that of the first magnetoresistance element720bare different from each other so that the orientations of the imaginary C-shaped features C61become different. That is, the orientation of the circumferential direction of the pattern720of the first magnetoresistance element720aand that of the first magnetoresistance element720bare different from each other so that the orientation of the C-shaped pattern721of the first magnetoresistance element720aand that of the first magnetoresistance element720bbecome different.

In the tenth preferred embodiment, the orientation of the circumferential direction of the pattern720of the first magnetoresistance element720aand that of the first magnetoresistance element720bdiffer from each other by about 135°, for example, so that the orientation of the C-shaped pattern721of the first magnetoresistance element720aand that of the first magnetoresistance element720bbecome different from each other by about 135°, for example.

The patterns630of the second magnetoresistance elements630aand630bpreferably have the same or substantially the same thickness as the patterns720of the first magnetoresistance elements720aand720b. However, the patterns630may be thinner than the patterns720.

In the magnetic sensor7according to the tenth preferred embodiment, the second magnetoresistance elements630aand630bare provided inward of the first magnetoresistance elements720aand720b, respectively, and thus the size of the magnetic sensor is able to be significantly reduced. Additionally, in the magnetic sensor7, too, it is not necessary to three-dimensionally lay the wiring to connect the first magnetoresistance elements720aand720band the second magnetoresistance elements630aand630b. Thus, the circuit substrate700is able to be manufactured with a simple manufacturing process.

As shown inFIG. 33, the first magnets40bdo not cover the first magnetoresistance elements720aand720b, but cover the second magnetoresistance elements630aand630b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

The magnetic sensor7according to the tenth preferred embodiment is also able to detect a vertical magnetic field and a horizontal magnetic field with high sensitivity. In the magnetic sensor7according to the tenth preferred embodiment of the present invention, each of the first magnetoresistance elements720aand720bincludes the first pattern provided along the circumference thereof, thus improving the isotropic characteristics in detecting a horizontal magnetic field.

In the tenth preferred embodiment, the second magnetoresistance elements630aand630bare magnetically shielded by the first magnets40band hardly detect vertical magnetic fields and horizontal magnetic fields. The resistance change rate of the second magnetoresistance elements630aand630bmay not necessarily be smaller than that of the first magnetoresistance elements720aand720b.

The magnetic sensor7according to the tenth preferred embodiment of the present invention also provides high isotropic characteristics in detecting a horizontal magnetic field and is also able to detect a weak vertical magnetic field by using magnetoresistance elements. The magnetic sensor7is also able to regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements.

In the magnetic sensor7according to the tenth preferred embodiment, as the distance between the inner peripheral edge of each of the first magnetoresistance elements720aand720band the outer peripheral edge of the first base section41bof the first magnet40b, a sufficiently large distance is provided so that the first magnetoresistance elements720aand720bdo not overlap the first magnets40beven if the positions of the first magnets40bwhen being formed by plating are varied. Thus, a stress is less likely to be applied from the first magnets40bto the first magnetoresistance elements720aand720bvia the corresponding stress relaxers.

Eleventh Preferred Embodiment

A magnetic sensor according to an eleventh preferred embodiment of the present invention will be described below with reference to the drawings. The magnetic sensor according to the eleventh preferred embodiment of the present invention is different from the magnetic sensor6of the ninth preferred embodiment of the present invention mainly in the pattern of the second magnetoresistance elements and the first magnets. An explanation of elements similar to those of the magnetic sensor6of the ninth preferred embodiment of the present invention will not be repeated.

FIG. 35is a plan view of the magnetic sensor according to the eleventh preferred embodiment of the present invention.FIG. 36is a plan view showing a pattern of a first magnetoresistance element and that of a second magnetoresistance element of the magnetic sensor according to the eleventh preferred embodiment of the present invention. InFIGS. 35 and 36, the inner peripheral edges and the outer peripheral edges of the first magnets are indicated by the dotted lines.

As shown inFIG. 35, a magnetic sensor8according to the eleventh preferred embodiment of the present invention includes a circuit substrate800and two first magnets40cprovided above the circuit substrate800. Each first magnet40cincludes a first base section41and a first narrow section42c. The area of the exterior surface of the first narrow section42cas viewed from the direction perpendicular or substantially perpendicular to the insulating layer30is smaller than that of the first base section41. The first base section41and the first narrow section42cas viewed from the direction perpendicular or substantially perpendicular to the insulating layer30each have an externally circular shape. The first narrow section42cis eccentric from the first base section41, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. In the magnetic sensor8according to the eleventh preferred embodiment of the present invention, a gap is provided between the first base section41of the first magnet40cand the circuit substrate800all around the outer peripheral portion of the first magnet40c. A first stress relaxer is provided in the entirety of this gap.

As shown inFIG. 36, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, a second magnetoresistance element830ais positioned at the central side of the imaginary circle C6and is surrounded by a first magnetoresistance element620a, while a second magnetoresistance element830bis positioned at the central side of the imaginary circle C6and is surrounded by a first magnetoresistance element620b. That is, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the second magnetoresistance element830ais located farther inward than the inner peripheral edge of the first magnetoresistance element620a, while the second magnetoresistance element830bis located farther inward than the inner peripheral edge of the first magnetoresistance element620b.

Each of the second magnetoresistance elements830aand830bhas a pattern830. The pattern830includes two arc patterns831, which are second patterns, provided along the circumference of the imaginary circle C6line-symmetrically to each other and side by side one another in the radial direction of the imaginary circle C6. The two arc patterns831are connected with each other at one end by a semi-circular pattern832and at the other end by a semi-circular pattern833. In the second magnetoresistance element830a, the arc pattern831positioned on the outermost side from the center of the imaginary circle C6is connected to the wiring146and148by a linearly extending portion834having a length shorter than about 10 μm, for example. In the second magnetoresistance element830b, the arc pattern831positioned on the outermost side from the center of the imaginary circle C6is connected to the wiring150and152by a linearly extending portion834having a length shorter than about 10 μm, for example.

In the second magnetoresistance element830a, as the distance between the inner peripheral edge of the arc pattern831positioned closer to the center of the imaginary circle C6and the outer peripheral edge of the first narrow section42cof the first magnet40c, a sufficiently large distance is provided so that the second magnetoresistance elements830aand830bdo not overlap the first narrow sections42cof the first magnets40ceven if the positions of the first magnets40cwhen being formed by plating are varied.

The patterns830of the second magnetoresistance elements830aand830bpreferably have the same or substantially the same thickness as the patterns620of the first magnetoresistance elements620aand620b. However, the patterns830may be thinner than the patterns620.

In the magnetic sensor8according to the eleventh preferred embodiment, each of the second magnetoresistance elements830aand830bhas the arc patterns831. The arc patterns831are formed of arcs. The two adjacent arc patterns831are connected with each other by the semi-circular patterns832and833. Each of the second magnetoresistance elements830aand830bincludes the linearly extending portion834merely having a length shorter than about 10 μm. Accordingly, the anisotropic characteristics in detecting a magnetic field are able to be significantly reduced.

The orientation of the circumferential direction of the pattern830of the second magnetoresistance element830aand that of the second magnetoresistance element830bare different from each other. In the eleventh preferred embodiment, the orientation of the circumferential direction of the pattern830of the second magnetoresistance element830aand that of the second magnetoresistance element830bare different from each other by about 135°, for example. Accordingly, the anisotropic characteristics of the magnetoresistance effect of the second magnetoresistance element830aand that of the second magnetoresistance element830bare able to be offset from each other and be reduced to a smaller level.

In the magnetic sensor8according to the eleventh preferred embodiment, too, the second magnetoresistance elements830aand830bare provided inward of the first magnetoresistance elements620aand620b, respectively, and thus the size of the magnetic sensor8is able to be significantly reduced. Additionally, in the magnetic sensor8, too, it is not necessary to three-dimensionally lay the wiring to connect the first magnetoresistance elements620aand620band the second magnetoresistance elements830aand830b. Thus, the circuit substrate800is able to be manufactured with a simple manufacturing process.

As shown inFIG. 35, the first magnets40cdo not cover the first magnetoresistance elements620aand620b, but cover the second magnetoresistance elements830aand830b, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30.

In the eleventh preferred embodiment, the second magnetoresistance elements830aand830bare magnetically shielded by the first magnets40cand hardly detect vertical magnetic fields and horizontal magnetic fields. The resistance change rate of the second magnetoresistance elements830aand830bmay not necessarily be smaller than that of the first magnetoresistance elements620aand620b.

The magnetic sensor8according to the eleventh preferred embodiment of the present invention also provides high isotropic characteristics in detecting a horizontal magnetic field and is also able to detect a weak vertical magnetic field by using magnetoresistance elements. The magnetic sensor8is also able to regulate a decrease in the output accuracy, which would be caused by a stress applied to the magnetoresistance elements from a structure provided above the magnetoresistance elements.

In the magnetic sensor8according to the eleventh preferred embodiment, as the distance between the inner peripheral edge of the arc pattern831positioned closer to the center of the imaginary circle C6and the outer peripheral edge of the first narrow section42cof the first magnet40c, a sufficiently large distance is provided so that the second magnetoresistance elements830aand830bdo not overlap the first narrow sections42cof the first magnets40ceven if the positions of the first magnets40cwhen being formed by plating are varied. Thus, a stress is less likely to be applied from the first narrow sections42cof the first magnets40cto the second magnetoresistance elements830aand830b.

In the magnetic sensor8according to the eleventh preferred embodiment, the first narrow section42cis eccentric from the first base section41, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30. Accordingly, as viewed from the direction perpendicular or substantially perpendicular to the insulating layer30, the shortest distance between the center of the first narrow section42cand the second magnetoresistance elements830aand830bis longer than that between the center of the first base section41and the second magnetoresistance elements830aand830b. Thus, the second magnetoresistance elements830aand830bare able to be located immediately under a vicinity of the center of the first base section41of the first magnet40cwhich exhibits a high shielding effect, while a stress is even less likely to be applied from the first narrow section42cof the first magnet40cto the second magnetoresistance elements830aand830b.

In the above-described preferred embodiments, some of the features, components, and elements may be combined with each other within a technically possible range.

The preferred embodiments described herein are provided only for the purposes of illustration, but are not intended to be exhaustive or to limit the invention to the precise forms disclosed. It is intended that the scope of the invention be defined, not by the foregoing preferred embodiments, but by the following claims. The scope of the present invention is to be accorded the broadest interpretation to encompass all such modifications and equivalent structures and functions.