Electronic apparatus including semiconductor package

An electronic apparatus includes a semiconductor package including a sensor unit that outputs a signal responding to an applied physical quantity, mounted on a mounting member. An island projected region is defined as a region in the mounting member obtained by projecting an outline of an island on which the sensor unit is mounted, and a part of or entire of the island projected region is configured as a through hole or a concave portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims the benefit of priority from earlier Japanese Patent Application No. 2020-154596 filed Sep. 15, 2020, the description of which is incorporated herein by reference.

BACKGROUND

Technical Field

The present disclosure relates to an electronic control apparatus including a semiconductor package mounted thereon, in which a sensor unit that outputs a signal responding to an applied physical quantity is provided.

Description of the Related Art

Conventionally, an electronic control apparatus is disclosed which is provided with a sensor body including a sensor unit in a concave section and a semiconductor package mounted on a printed wiring board, including a protection member that seals the sensor unit while covering the sensor unit without touching with the sensor unit. The sensor unit is configured as a micro electro mechanical system (i.e. MEMS) which outputs a signal, when a predetermined physical quantity such as an acceleration factor, a pressure, an angular velocity is applied, responding to the applied physical quantity.

SUMMARY

The present disclosure provides an electronic apparatus including: a semiconductor package including a sensor unit that outputs a signal responding to an applied physical quantity, an island on which the sensor unit is mounted, a lead frame having a plurality of leads and a sealing resin that covers a part of the lead frame and the sensor unit; and a mounting member including a substrate having a front surface that faces the semiconductor package and a back surface, the semiconductor package being mounted on the mounting member via a bonding material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Conventionally, as an electronic apparatus, for example, patent literature JP-A-2007-214440 discloses an electronic control apparatus provided with a sensor body including a sensor unit in a concave section and a semiconductor package mounted on a printed wiring board, including a protection member that seals the sensor unit while covering the sensor unit without touching with the sensor unit.

The sensor unit is configured as a micro electro mechanical system (i.e. MEMS) which outputs a signal, when a predetermined physical quantity such as an acceleration factor, a pressure, an angular velocity is applied, responding to the applied physical quantity.

According to the above-described electronic control apparatus, since the sensor unit is disposed in a cavity, the sensor unit is unlikely to be influenced by a stress caused by a difference of the linear expansion coefficient between devices on the printed wiring board and the sensor body even it is used in an environment having large temperature change. Hence, the signal output is stable. Note that a use of the above-described apparatus is not limited, but may be an on-vehicle use such as vehicles, for example.

In recent years, in the field of this type of electronic apparatus, further downsizing is required. However, in the case where the sensor is configured to have a cavity, since the dimension of the semiconductor package in the thickness direction becomes large, further downsizing of the electronic apparatus cannot be accomplished.

With reference to the drawings, embodiments of the present disclosure will be described. Note that mutually the same or equivalent portions in the respective embodiments will be described with the same reference numbers applied thereto.

First Embodiment

With reference toFIGS.1to4, an electronic apparatus1according to a first embodiment will be described.

InFIG.1, in order to view easily for recognizing the elements, a part of a land42and outline of an island projected region41cin the mounting member4(described later), which are hidden by the semiconductor package2in top view, are shown with a two-dot chain line. Also, inFIG.1, with the same purpose as described above, the outline of the sensor unit21which will be described later in the semiconductor package2is shown with a dotted line. InFIG.3, for ease of illustration, the outline of the sealing resin26which will be described later in the semiconductor package2is shown with a two-dot chain line, and the outline of the respective elements arranged in the sealing resin26are shown with a solid line.

Hereinafter, for convenience of explanation, as shown with an arrow inFIG.1, a direction towards the right on the paper surface is referred to as X direction, a direction orthogonal to the X direction on the same paper surface and towards the upper side on the paper surface is referred to as Y direction, and a direction orthogonal to a XY plane and towards the rear side of the paper surface is referred to as Z direction. In the drawings subsequent toFIG.1, the directions X, Y, Z correspond to respective directions X, Y, Z shown inFIG.1.

An electronic apparatus1according to the present embodiment is provided with a semiconductor package2having a sensor unit21that outputs a signal responding to an applied physical quantity, and a mounting member4to which the semiconductor package2is mounted. For the electronic apparatus1, for example, as shown inFIG.2, the semiconductor package2is mounted on a mounting member4via a bonding material3, and at least a region in the mounting member4, which is immediately below the sensor unit21of the semiconductor package2, is a through hole411. Thus, the electronic apparatus1is configured such that the semiconductor package2does not come into contact with the mounting member4in the case where the semiconductor package2is curved towards the mounting member4with thermal deformation.

As shown inFIGS.2and3, the semiconductor package2is provided with, a sensor unit21, a signal processing unit22, an adhesive material23, an island241, a lead frame24having a plurality of leads242, a wire25and a sealing resin26. In view of downsizing, as shown inFIG.3, for example, the semiconductor package2is configured as a QFN (quad flat non-leaded package) structure in which all of the leads242are disposed inside the outline of the sealing resin26. In other words, the semiconductor package2has a smaller planar size compared to that of a QFP (quad flat package) structure having outer leads protruding from the sealing resin26. Hence, the structure of the semiconductor package2is suitable for downsizing the electronic apparatus1.

The sensor unit21is an electronic component in which a MEMS sensor that outputs a signal responding to physical quantity applied externally is formed on a substrate made of Si (silicon) or a glass. When the sensor unit21is a MEMS sensor, the semiconductor package2, that is, the electronic apparatus1, can be further downsized. The sensor unit21functions as, for example, an inertial sensor such as an acceleration sensor and an angular velocity sensor, and outputs, when various physical quantity such as the acceleration factor, the angular velocity and the like are applied, a signal responding to the physical quantity. The sensor unit21is configured as, for example, as shown inFIG.2, a semiconductor element disposed on the signal processing unit22and connected to electrodes (not shown) of the signal processing unit22with any method such as a thermal bonding. Thus, the sensor unit21is configured such that the output signal to be outputted responding to the physical quantity when being applied, is transmitted to the signal processing unit22.

In the present specification, a case will be described as a typical example in which the sensor unit21is configured as an acceleration sensor outputting a signal responding to an acceleration factor in a thickness direction of the semiconductor package2, that is, Z direction. However, this is not limited to this example.

When the sensor unit21is configured as an acceleration sensor that detects an acceleration factor in the Z direction, that is, the gravitational acceleration, for example, as shown inFIG.4, the sensor unit is an electrostatic capacitance detection type MEMS sensor including a fixed electrode211, a movable electrode212, and a spring member213. In this case, the sensor unit21is configured to output a signal responding to a change in the electrostatic capacitance based on a change in the distance d1between the fixed electrode211and the movable electrode212. For example, the electrostatic capacitance C (unit: F) between the fixed electrode211and the movable electrode212which have the same area S (unit: m2) is calculated by the following equation (1), where the dielectric constant of the dielectric between the electrodes211and212is ε(unit: F/m).
C=ε·S/d1  (1)
where mass of the movable electrode21serving as a weight is nn (unit: kg), the spring constant of the spring member213is k (unit: N/nn), and a moving distance of the movable electrode212is d2(unit: nn) as shown inFIG.4.

Here, the acceleration a in the Z direction applied to the sensor unit21is calculated by the following equation (2).
α=k·d2/m(2)
Specifically, the distance d1between the fixed electrode211and the movable electrode212is calculated based on a change in the electrostatic capacitance C, and the moving distance d2of the movable electrode212is calculated based on the distance d1, whereby the acceleration a in the Z direction applied to the sensor unit21can be calculated. For example, the sensor unit21is configured such that the outer surface in the fixed electrode211side shown inFIG.4is bonded to the signal processing unit22, and the output signal thereof is directly transmitted to the signal processing unit22via a wiring connected to the fixed electrode211.

As a detection method of the acceleration factor of the acceleration sensor, a piezoresistance method and a thermal detection method can be used other than the electrostatic capacitance detection method. Since the sensor unit21of the electrostatic capacitance detection method can be accomplished by stable material such as glass or Si, the sensor characteristics in a temperature in an environment of the sensor unit21is stabilized. Hence, electrostatic capacitance detection method has superior temperature characteristics compared to other methods.

For example, the signal processing unit22is an electronic component provided with an integrated circuit (IC) which is not shown, processing the output signal transmitted from the sensor unit21, and that is a semiconductor element. For example, the signal processing unit22is configured to convert an analog signal outputted by the sensor unit21into a digital signal and output the converted digital signal externally. As shown inFIG.3, in the signal processing unit22, wires25are connected to electrodes (not shown), and a plurality of leads242are electrically connected to the signal processing unit22via the wires25. Thus, the signal processed by the signal processing unit22is transmitted externally via the leads242. As shown inFIG.2, the signal processing unit22is mounted on the island241by the adhesive material23, for example.

For the adhesive material23, for example, any materials which are generally used in a semiconductor packaging area can be used.

The lead frame24is provided with the island241on which the signal processing unit22and the sensor unit21are mounted, and the plurality of leads242separated from the island241. The lead frame24is made of, for example, any conductive materials including metals such as Cu (copper), Fe (iron) and composite materials thereof. For the lead frame24, the island241and the plurality of leads242are coupled by a tie bar (not shown) or the like before the forming process of the sealing resin26, and after forming the sealing resin26, a coupled portion is cut and removed by a punching process or the like, thereby separating the coupled portion.

As shown inFIG.2, for the island241, a surface on which the signal processing unit22is mounted and an opposite surface are exposed from the sealing resin26. Note that the island241has a symmetric shape such as rectangular shape where the center thereof in the top view is defined as the axis, and the island241is disposed such that the center thereof is overlapped with the center of the sensor unit21. However, the configuration is not limited thereto.

As shown inFIG.2, for the plurality of leads242, a first surface on which the wire25is connected and a second surface opposite to the first surface are exposed from the sealing resin26, serving as connection terminals to the mounting member4. For the plurality of leads242, a side surface connecting the first surface and the second surface, being opposite to a surface facing the island241is exposed from the sealing resin26. As shown inFIG.3, the plurality of leads242are arranged with a distance from the island241and apart from each other to surround the island241.

Note that the number of islands241and the leads242which constitute the lead frame24, the size and arrangement of the islands241and the leads242are not limited to the configurations shown inFIGS.2and3, but may be appropriately modified.

The wires25are each composed of any conductive material such as Au (gold) and each connected to the signal processing unit22and the lead242.

The sealing resin26is composed of any insulated resin material such as epoxy resin, and formed by any resin molding method such as a compression molding.

The sealing resin26touches all the area of the sensor unit21excluding a portion in the island241side. In other words, the sealing resin26is configured not to include a cavity for disposing the sensor unit21inside the semiconductor package2. That is, the semiconductor package2is configured as a QFN structure in which the sensor unit21is fully molded by the sealing resin26.

The bonding material3is made of any conductive bonding material used for bonding the semiconductor package2to the mounting member4, such as solder.

In order to distinguish the members and for the sake of convenience, a member for mounting the signal processing unit22onto the island241is referred to as an adhesive material23, and a member for mounting the semiconductor package2onto the mounting member4is referred to as a bonding material3. However, these materials may be formed of the same material.

As shown inFIG.2, the mounting member4is provided with a substrate41having a front surface41aand a back surface41b, a land42formed on the front surface41a, and an insulation layer43. The mounting member4is, for example, a printed circuit board. The mounting member4is not limited to the printed circuit board but may be any member as long as the semiconductor package2can be mounted. For the mounting member4, a region where the outline of the island241is projected along a normal line, with respect to the front surface41aof the substrate41, is referred to as an island projected region41c. All the area of the island projected region41cis formed as a through hole411which connects the front surface41aand the back surface41b. In other words, the mounting member4has a region as a through hole411, which is produced by projecting, in the Z direction, the outline of the island241provided with the sensor unit21mounted thereon, that is, a region located immediately below the island241. This structure prevents the semiconductor package2from coming into contact with the mounting member4when the semiconductor package2is curved towards the mounting member4because of temperature change, and stabilizes the sensor characteristics of the sensor unit21. This structure will be detailed later.

The substrate41is a plate-like member made of any insulation material such as glass epoxy resin, for example. As shown inFIG.2, the substrate41includes the land42and the insulation layer43that covers at least a part of the front surface41a, in the front surface31aside as a surface for mounting the semiconductor package2.

The substrate41can be configured such that the back surface41bside is exposed, but it is not limited to this configuration. The substrate41may be configured such that the land42and the insulation layer43are provided in the back surface41bside.

The land42is made of any conductive material such as Cu, and used for boding with other members. For example, the land42is constituted such that the one end side is bonded to the lead242of the semiconductor package2via the bonding material3, and the other end side is bonded to a wiring which is not shown. Note that the number of lands42, and the size and the shape of the lands42may be appropriately modified depending on an arrangement of the lead42of the semiconductor package2.

The insulation layer43covers at least a part of the front surface41aof the substrate41and the land42, and is made of any insulation resin material. The insulation layer43may be a solder resist generally used in a field of electronic substrates.

The basic configuration of the electronic apparatus1according to the present embodiment is described in the above.

The effects and advantages of the electronic apparatus1according to the present embodiment will be described with reference toFIGS.6and7. Firstly, with reference toFIGS.5A to5D, a problem in an electronic apparatus according to a comparative example (conventional art) will be described. The electronic apparatus100according to the comparative example is configured such that a QFN type semiconductor package2without through hole is mounted on the printed circuit board5.

InFIGS.5B and5C, the white arrow indicates a direction where the semiconductor package2and the printed circuit board5are expanded or contracted with a temperature in an environment of the electronic apparatus100according to the comparative example. Hereinafter, for the sake of convenience, the temperature in an environment of the electronic apparatus100according to the comparative example, or the electronic apparatus1according to the present embodiment is referred to as ambient temperature.

InFIG.5C, a dotted line indicates an outline of the semiconductor package2in a state where the semiconductor package2comes into contact with the printed circuit board5. InFIG.5D, for ease of illustration, the solid line indicates a graph showing the sensor output corresponding to a left side vertical axis, and the one dot chain line indicates a graph showing the ambient temperature corresponding to a right side vertical axis. The same applies toFIG.7.

As shown inFIG.5A, for example, the electronic apparatus100according to the comparative example is configured such that the QFN structured semiconductor package is bonded to the printed circuit board5via the bonding material3. The printed circuit board5is composed of a flat plate-shaped substrate51, a copper foil52disposed on the front surface51aof the substrate51, and a solder resist53that covers at least a part of the front surface51aand the copper foil52. The substrate51is made of any insulation material such as glass epoxy resin, and the concave section and the through hole are not provided in a region immediately below the semiconductor package2.

The ambient temperature which will be described below is not limited to the normal temperature, but may be an air temperature ranging from 15 deg. C. to 25 deg. C., for example. A high temperature is not limited to any value, but may be a temperature exceeding a normal air temperature (e.g. 50 deg. C. or higher). Further, a low temperature is not limited to any value, but may be a temperature below a normal air temperature (e.g. 0 deg. C. or lower).

In the electronic apparatus100according to the comparative example, when the ambient temperature changes from the normal temperature to the high temperature, as indicated by the white arrow inFIG.5B, the semiconductor package2and the printed circuit board5are expanded with the heat. At this time, a degree of thermal expansion of the printed circuit board5is larger than that of the semiconductor package2with the difference of the linear expansion coefficient between materials of the constituents thereof. As a result, in the semiconductor package2, one surface between the outer front surfaces thereof positioned in the printed circuit board5side is curved to be in a convex shape, and the island241including the sensor unit21mounted thereon comes into contact with the printed circuit board5as shown inFIG.5B.

The inventors have discovered, through diligent research into the electronic apparatus100of the comparative example, that the accuracy of the sensor is lowered and a discontinuity of the sensor output which will be described later occurs because of abutting and peeling between the semiconductor package2and the printed circuit board5.

Specifically, in the case where the semiconductor package2comes into contact with the printed circuit board5, an impact occurring when the semiconductor package2comes into contact with the printed circuit board5is propagated to the sensor unit21, and noise may be produced on the output signal from the sensor unit21. Also, in the state where the semiconductor package2is in contact with the printed circuit board5, in the sensor unit21, the fixed electrode211which is close to the printed circuit board5is more prevented from being deformed compared to the variable electrode212which is farther from the printed circuit board5than the fixed electrode211is. Thus, even in the case where the physical quantity is not applied, in the sensor unit21, the distance d1between the fixed electrode211and the variable electrode212becomes small, whereby the trend of the output signal changes and the accuracy of the sensor may be lowered.

On the other hand, in the electronic apparatus100according to the comparative example, when the ambient temperature changes from the normal temperature to the low temperature, as indicated by the white arrow inFIG.5C, the semiconductor package2and the printed circuit board5are contracted with the drop in temperature. At this time, a degree of thermal contraction of the printed circuit board5is larger than that of the semiconductor package2with the difference of the linear expansion coefficient between materials of the constituents thereof. As a result, in the semiconductor package2, the other surface opposite to the one surface between the outer front surfaces thereof is curved to be in a convex shape, and deformed receding from the printed circuit board5.

Here, as a result of inventor's research, when a solder is used as a bonding material4, it is found that the accuracy of the sensor unit21of the semiconductor package2is significantly lowered.

Specifically, when using a solder as the boding material3, for example, as shown inFIG.5C, a flux F may be flowing into a region immediately below the semiconductor package2in the printed circuit board5. As described above, when the semiconductor package2comes into contact with the printed circuit board5, the semiconductor package2is temporarily stuck to the printed circuit board5by the flux F having adhesiveness. Thereafter, when the ambient temperature becomes low, the semiconductor package2is temporarily prevented from being deformed with the stuck flux F, but when a degree of deformation reaches a certain level, the semiconductor package2detaches from the flux F and is deformed, rapidly separating from the printed circuit board5. At this moment, an unintended force is applied to sensor unit21other than the physical quantity from outside when the semiconductor package2is peeled off from the flux F, which is reflected to the output signal. Hence, as shown inFIG.5D, a discontinuous portion occurs in the sensor output of the sensor unit21.

In order to solve the above-described issues, the inventors of the present disclosure developed an electronic apparatus1configured such that portions other than the bonded portion in the semiconductor package2does not come into contact with the mounting member4even when the semiconductor package2is deformed because of the ambient temperature.

According to the electronic apparatus1of the present embodiment, an island projected region41cin the mounting member, positioned immediately below the island241where the sensor unit21of the semiconductor package2is mounted, serves as a through hole411. Hence, as shown inFIG.6, for example, even when the semiconductor package2is curved in an arched shape approaching to the mounting member4side, since a portion in a convex shape of the semiconductor package2is positioned above the through hole411, an unintended portion does not come into contact with the mounting member4. Further, since the island projected region41cserves as the through hole411, even when the bonding material is a solder, the flux F does not flow into a portion immediately below the semiconductor package2and does not stay in the portion immediately below the semiconductor package2.

Accordingly, the electronic apparatus1of the present disclosure has a configuration in which the accuracy of the sensor unit21is improved compared to the above-described comparative example. Also, in the electronic apparatus1, since an unintentional contact between the semiconductor package2and the mounting member4does not occur, even when a solder is used as the bonding material3, for example, as shown inFIG.7, the sensor output is stable and discontinuity of the sensor output does not occur.

Note that the semiconductor package may be configured to have a QFP structure and designed such that the thermal stress due to a difference of the linear expansion coefficients between the outer lead part protruding from the sealing resin and the mounting member is relaxed to prevent the semiconductor package from being deformed, thereby stabilizing the sensor output. However, in the case of the QFP structure, since the planar size becomes larger due to the outer lead part, it may be insufficient to satisfy a requirement of downsizing the electronic apparatus.

In contrast, the electronic apparatus1according to the present embodiment has a QFN structure for the semiconductor package2. Hence, since the outer lead protruding from the outline of the sealing resin26is not present, the planar size of the apparatus is smaller than that of the QFP structure.

According to the present embodiment, the semiconductor package2having QFN structure is mounted to the mounting member4in which the through hole411is the island projected region41cpositioned immediately below the island241where the sensor unit21is mounted, thereby constituting the electronic apparatus. Thus, even in the case where the semiconductor package2is deformed because of the ambient temperature, the semiconductor package2does not unintentionally come into contact with the mounting member4. Therefore, both of the downsizing of the electronic apparatus and a stable sensor output can be accomplished.

Modification of First Embodiment

The sensor unit21may be disposed not on the signal processing unit22, but disposed a distance away from the signal processing unit22and mounted to another region in the island241other than a region where the signal processing unit22is mounted. In this case, the sensor unit21is electrically connected to the signal processing unit22at an electrode portion (not shown) via a second wire252. Note that a first wire251connects between the signal processing unit22and the lead242. Thus, the output signal from the sensor unit21is transmitted to the signal processing unit22via the second wire252.

For the mounting member4, similar to the above-described embodiment, for example, as shown inFIG.9, the through hole411is defined as an island projected region41cproduced by projecting, in the Z direction, the outline of the island241provided with the sensor unit21mounted thereon.

According to the present modification, the same effect and advantages as those in the above-described first embodiment can be obtained.

Second Embodiment

An electronic apparatus1according to the second embodiment will be described with reference toFIG.10andFIG.11.

InFIG.10, in order to easily recognize the structure of the convex portion44(described later) in the mounting member4, the outline of the semiconductor package2is indicated by a two-dot chain line, the outline of the sensor unit21is indicated by a dotted line, and a hatching is applied to the convex portion44. Note that this hatching does not indicate a cross-section.

The electronic apparatus1according to the present embodiment differs from the first embodiment in that the mounting member4further includes a convex portion44used for adjusting a gap between the semiconductor package2and the substrate41. According to the present embodiment, this difference will be mainly described.

The convex portion44is a member for adjusting a gap such that the distance between the semiconductor package2and the substrate41is a predetermined distance or more when mounting the semiconductor package2on the mounting member4. The convex portion44further prevents the semiconductor package2and the substrate41from coming into contact with each other when the semiconductor package2is deformed due to changes in the ambient temperature.

For the convex portion44, for example, as shown inFIG.10, a plurality of convex portions44are arranged in a region in the substrate41which is formed by projecting the outline of the semiconductor package2in the Z direction, that is, a region immediately below the semiconductor package3and a region positioned outside the island projected region41c. Hereinafter, to simplify the explanation, the above-described region where the convex portions44are arranged within a region of the substrate41where the outline of the semiconductor package2is projected in the Z direction, may be referred to as convex portion arrangement portion. For example, four convex portions44are arranged to support the four corner portions of the semiconductor package2. However, it is not limited to this configuration as long as the gap between the semiconductor package2and the substrate41are adjusted, and the number of portions, the planar size, the height, the shape or the arrangement may be appropriately changed.

The height of the convex portion44in the convex portion arrangement region of the substrate41may be set corresponding to a predetermined distance or less such that a bonding failure does not occur between the semiconductor package2and the substrate41while protruding in the Z direction from other portions such as the land42and the insulation layer43.

For example, as shown inFIG.11, the convex portion44is formed on the insulation layer23. In this case, the convex portion44is formed using an insulation material which is film-formed by any method such as a dispenser coating or a silk printing. Note that the under coating of the convex portion44is not limited to the insulation layer23, but may be any coating such as a laminate of a dummy land and the insulation layer43, and the substrate41.

According to the present embodiment, in addition to the configuration in which the island projected region41cof the mounting member4is the through hole411, the convex portion44is provided for adjusting the gap. Hence, the semiconductor package2is unlikely to come into contact with the mounting portion4, thereby further improving the effects and advantages obtained from the first embodiment.

Third Embodiment

An electronic apparatus according to the third embodiment will be described with reference toFIG.12.

The electronic apparatus1according to the present embodiment differs from the first embodiment in that the island projected region41cin the mounting member4is the concave portion412. According to the present embodiment, this difference will be mainly described.

The mounting member4according to the present embodiment is configured as a concave portion412in which entire island projected region41cis recessed from the front surface41aof the substrate41towards the back surface41bof the substrate41. Thus, the semiconductor package is prevented from coming into contact with the substrate41because the island projected region41cis configured as the convex portion412, even when it is curved towards the substrate41side because of an influence of the ambient temperature. For the concave portion412, the depth, the shape and the planar size of may be appropriately changed, as long as the concave portion412is required to be configured such that the semiconductor package2curved towards the substrate41side does not come into contact with the substrate41. In the case where the island projected region41cis the concave portion412, when using a solder as the boding material3, the flux F stays in the bottom portion of the concave portion412, but never come into contact with the semiconductor package2.

According to the present embodiment, effects and advantages similar to those in the first embodiment can be obtained from the electronic apparatus1of the present embodiment.

Other Embodiments

The present disclosure has been described in accordance with the embodiments. However, the present disclosure is not limited to the embodiments and structure thereof. The present disclosure includes various modification examples and modifications within the equivalent configurations. Further, various combinations and modes and other combinations and modes including one element or more or less elements of those various combinations are within the range and technical scope of the present disclosure.

For example, according to the above-described respective embodiments, examples are described in which the entire island projected region41cin the mounting portion4is configured as the through hole411or the concave portion412. However, it is not limited to these examples. Specifically, the island projected region41cmay have a shape in which the semiconductor package2and the substrate51do not come into contact with each other when the semiconductor2is curved towards the substrate41side. Hence, a part of the island projected region41cmay be configured as the through hole411or the concave portion412. For example, the though hole411or the concave portion412may be configured as a region positioned immediately below a predetermined region in the island projected region41cincluding the center of the island241where the sensor unit21is mounted, or a part of a predetermined region immediately below the sensor unit21.

Conclusion

The present disclosure has been achieved in light of the above-described circumstance, and provides an electronic apparatus including a semiconductor package provided with a sensor unit outputting a signal responding to an applied physical quantity. The electronic apparatus accomplishes both of downsizing of the electronic apparatus and stable output of the sensor unit.

As a first aspect, the present disclosure provides an electronic apparatus including: a semiconductor package including a sensor unit that outputs a signal responding to an applied physical quantity, an island on which the sensor unit is mounted, a lead frame having a plurality of leads and a sealing resin that covers a part of the lead frame and the sensor unit; and a mounting member including a substrate having a front surface that faces the semiconductor package and a back surface, the semiconductor package being mounted on the mounting member via a bonding material. An island projected region is defined as a region in the substrate obtained by projecting an outline of the island along a normal line with respect to the front surface, and a part of or entire of the island projected region is configured as a through hole that connects between the front surface and the back surface, or configured as a concave portion recessed from the front surface towards the back surface.

Thus, according to the electronic apparatus of the present disclosure, even in a case where a stress due to a difference of thermal expansion or contraction between the semiconductor package and the mounting member occurs and causes the semiconductor package to be curved towards the mounting member side, the semiconductor package is prevented from coming into contact with the mounting member because of the curved shape thereof. Specifically, a part of or entire region in the mounting member immediately below the island where the semiconductor package is mounted, is configured as a through or a concave portion, whereby the semiconductor package does not come into contact with the mounting member when being curved and the sensor output is stabilized. Further, since the electronic apparatus is structured such that the semiconductor package, when being curved, does not come into contact with the mounting member, a cavity portion for disposing the sensor unit in the semiconductor package is not required to be provided. Hence, the electronic apparatus can be downsized in the thickness direction. Therefore, both of downsizing of the electronic apparatus and stable output of the sensor unit can be accomplished.