Patent Description:
Conventionally, it has been known that a semiconductor element is placed on a conductor layer of a substrate, and a front surface of the semiconductor element and a terminal are connected to each other with a connector via a conductive adhesive such as solder (<CIT>). Since the solder placed between the connector and the front surface of the semiconductor element tends to have a crack at a peripheral edge, it is preferable to increase a thickness of the peripheral edge. On the other hand, necessity of increasing a thickness of the solder is not very high at an area other than the peripheral edge.

Further, demand for flowing a large capacity of current into a semiconductor device is not small, which may increase a size of the semiconductor element or the connector. When a large semiconductor element or connector is mounted, a thickness of the conductive adhesive such as solder is required to be increased in order to secure reliability tolerance due to temperature change or the like. For that purpose, it is necessary to increase a coating amount of the conductive adhesive such as solder. On the other hand, an increase in the coating amount of the conductive adhesive causes higher risk of a solder bridge between electrodes on the front surface of the semiconductor element.

<CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT> disclose prior art.

In view of the above, it is an object of the present invention to provide a highly reliable electronic device that secures a thickness of a conductive adhesive while using an appropriate amount of the conductive adhesive, and to provide a connection body that can be used for such an electronic device.

According to the present invention, since the configuration has the second projection and the first projection, it is possible to increase a thickness of the conductive adhesive such as solder to a certain extent at an area not provided with the first projection, and to further increase the thickness of the conductive adhesive at an area not provided with the second projection and the first projection. Further, since the configuration has the second projection and the first projection, usage of the conductive adhesive can be reduced. Furthermore, the second projection can also be used to secure a width of a current path.

The invention is disclosed in the Second Embodiment.

As shown in <FIG>, a semiconductor device as an example of an electronic device of this embodiment has a substrate <NUM> made of an insulating material, and a conductor layer <NUM> provided on the substrate <NUM> and made of copper or the like. A back surface of the substrate <NUM> may be provided with a heat radiating plate <NUM> (see <FIG>) made of copper or the like. As shown in <FIG>, the semiconductor device has a sealing part <NUM> (see <FIG>) made of sealing resin or the like, a semiconductor element <NUM> provided in the sealing part <NUM> and a connection body <NUM> having a head part <NUM> connected to a front surface of the semiconductor element <NUM> via a conductive adhesive <NUM> such as solder (see <FIG>). In the present embodiment, as shown in <FIG>, the connection body <NUM> has a connector <NUM> having the head part <NUM> and a base end part <NUM> that is connected to a first main terminal <NUM> via the conductor layer <NUM>. In an aspect shown in <FIG>, the front surface sensing terminal <NUM> is electrically connected to the base end part <NUM> by a wire or the like (not shown). The semiconductor device may have the first main terminal <NUM> protruding outward from the sealing part <NUM>, and a second main terminal <NUM> protruding outward from the sealing part <NUM>.

In the present embodiment, explanation will be made using a semiconductor device as an electronic device, and the semiconductor element <NUM> as an electronic element. However, the present invention is not limited to this, and not particularly required to be a "semiconductor".

As shown in <FIG>, <FIG>, and <FIG>, the head part <NUM> has a second projection <NUM> protruding toward the semiconductor element <NUM>, and a first projection <NUM> protruding from the second projection <NUM> toward the semiconductor element <NUM>. While only one each of the first projection <NUM> and the second projection <NUM> are provided in this aspect, a plurality of the first projections <NUM> and a plurality of the second projections <NUM> may be provided as shown in <FIG> and <FIG>. Further, as shown in <FIG> and <FIG>, an aspect may be such that a part of a plurality of the second projections <NUM> is not provided with the first projection <NUM>.

When only one first projection <NUM> is provided, this first projection <NUM> may be positioned at a center position of the second projection <NUM> (see <FIG> and <FIG>). The first projection <NUM> being positioned at the center position of the second projection <NUM> means that the first projection <NUM> is positioned at a center of the second projection <NUM>, in a first direction and a width direction orthogonal to the first direction.

In the aspect shown in <FIG>, the second main terminal <NUM> is connected to the conductor layer <NUM>, and the second main terminal <NUM> is connected to a back surface of the semiconductor element <NUM> via the conductor layer <NUM>. On a peripheral edge of a connecting point of the second main terminal <NUM> with the conductor layer <NUM>, a resist (not shown) may be provided to prevent a conductive adhesive such as solder from flowing out. The back surface of the semiconductor element <NUM> and the conductor layer <NUM> may be connected via a conductive adhesive such as solder.

In the semiconductor element <NUM> shown in <FIG>, the front surface is electrically connected to the first main terminal <NUM>, and the back surface is electrically connected to the second main terminal <NUM>. In the present embodiment, there are provided a sensing terminal <NUM> on the front surface side (hereinafter referred to as a "front surface sensing terminal <NUM>") projecting outward from the sealing part <NUM> and used for sensing on a source side, and a connecting part <NUM> formed integrally with the head part <NUM> and electrically connected to the front surface sensing terminal <NUM>. In the present embodiment, explanation will be made while the first main terminal <NUM> through which a main current flows is used as a first terminal, and the front surface sensing terminal <NUM> through which a main current flows is used as a second terminal. However, the present invention is not limited to this. It is also possible to adopt an aspect in which the main current does not flow to the first terminal, or an aspect in which the second terminal is not used for sensing. Further, in the present embodiment, "coupled" includes an aspect of being "integrated".

In an aspect in which the connector <NUM> is used, the base end part <NUM> may have a supporting surface <NUM> and a recess <NUM> that is provided at a peripheral edge of the supporting surface <NUM>, as shown in <FIG>. The recess <NUM> may be provided to surround the entire supporting surface <NUM>, or may be formed to continuously surround three sides of the supporting surface <NUM> on the base end side, as shown in <FIG>. Additionally, the recess <NUM> may be formed to surround the supporting surface <NUM> intermittently, not continuously. Further, the base end part <NUM> may have a bent part <NUM> bent and extending toward the front surface side (an upper side in <FIG>). The recess <NUM> may extend to the front surface side along the bent part <NUM> extending from the supporting surface <NUM> to the front surface side. When adopting an aspect in which the recess <NUM> extends toward the front surface side along the bent part <NUM> in this way, it is advantageous in that a conductive adhesive can be provided along the recess <NUM> provided to the bent part <NUM>, and a fillet can be easily formed.

In an aspect in which the connector <NUM> is used, when a straight line connecting a center of the base end part <NUM> in a width direction (a vertical direction in <FIG>) and a center of the head part <NUM> in the width direction is defined as a first direction (a horizontal direction in <FIG>), a length of the supporting surface <NUM> along the first direction may be shorter than a length of the second projection <NUM> along the first direction (see <FIG>).

The first projection <NUM> may be positioned at the center in the width direction of the head part <NUM>.

The semiconductor element <NUM> may have a withstand voltage structure such as a guard ring. When the semiconductor element <NUM> has such a withstand voltage structure, as shown in <FIG>, there may be provided avoidance parts <NUM> and <NUM> that are integrally formed with the head part <NUM> and to avoid contact with the withstand voltage structure.

As shown in <FIG>, the avoidance parts <NUM> and <NUM> may have a first avoidance part <NUM> provided between the first main terminal <NUM> and the head part <NUM>, and a second avoidance part <NUM> provided between the front surface sensing terminal <NUM> and the head part <NUM>. The first avoidance part <NUM> may be a first recess 31a recessed so as to be separated from the semiconductor element <NUM>, and the second avoidance part <NUM> may be a second recess 32a recessed so as to be separated from the semiconductor element <NUM>. Note that <FIG> shows an aspect in which a recess is not used.

The first main terminal <NUM> and the second main terminal <NUM> may be power terminals through which a large current flows. When the first main terminal <NUM> and the second main terminal <NUM> are such power terminals, since a current flowing through the connector <NUM> is large, a size of the connector <NUM> is increased. This causes the connector <NUM> to easily sink into the conductive adhesive <NUM>.

As shown in <FIG> and the like, the front surface sensing terminal <NUM> and the connecting part <NUM> may be integrally formed with the head part <NUM>. However, the present invention is not limited to this, and for example, as shown in <FIG>, the connecting part <NUM> and the front surface sensing terminal <NUM> may be formed separately while the connecting part <NUM> and the head part <NUM> are formed integrally. As an example, the back surface of the connecting part <NUM> may be electrically connected to the front surface of the front surface sensing terminal <NUM> via a conductive adhesive or the like. Further, the first main terminal <NUM> and the head part <NUM> may be integrally formed. In addition, the front surface sensing terminal <NUM> and the first main terminal <NUM> may be provided extending in an opposite direction from the head part <NUM>.

In the aspect shown in <FIG>, as an example, a width of the connecting part <NUM> is larger than a width of the front surface sensing terminal <NUM>. Further, widths of the first avoidance part <NUM>, the head part <NUM>, and the second avoidance part <NUM> are larger than the width of the connecting part <NUM>, while widths of the first main terminal <NUM> and the second main terminal <NUM> are larger than the widths of the first avoidance part <NUM>, the head part <NUM>, and the second avoidance part <NUM>.

In an aspect shown in <FIG>, the second main terminal <NUM>, the front surface sensing terminal <NUM>, a back surface sensing terminal <NUM>, and a control terminal <NUM> protrude from one side surface of the sealing part <NUM> from outside, while the first main terminal <NUM> protrudes outward from another side surface of the sealing part <NUM>. The first main terminal <NUM>, the second main terminal <NUM>, the front surface sensing terminal <NUM>, the back surface sensing terminal <NUM>, and the control terminal <NUM> are bent toward the front surface side, and connected to a control substrate <NUM> provided on the front surface side. This control substrate <NUM> is used for controlling the semiconductor element <NUM>.

A structure inside the sealing part <NUM> of the semiconductor device may be line symmetrical. As an example, each of the first main terminal <NUM>, the second main terminal <NUM>, the front surface sensing terminal <NUM>, the back surface sensing terminal <NUM>, the control terminal <NUM>, and the conductor layer <NUM> may be arranged to be line symmetrical with respect to any given straight line. In addition, a wire <NUM> is also shown in <FIG>.

In an aspect in which the connector <NUM> is used, as shown in <FIG>, the aspect may be such that the base end part <NUM> of the connector <NUM> has a plurality of protrusions <NUM> in contact with the conductor layer <NUM>.

Next, functions and effects according to the present embodiment having the above-described configuration will be described.

According to the present embodiment, as shown in <FIG>, <FIG>, and the like, since the configuration has the second projection <NUM> and the first projection <NUM>, it is possible to increase a thickness of the conductive adhesive <NUM> such as solder to a certain extent at an area not provided with the first projection <NUM>, and to further increase the thickness of the conductive adhesive <NUM> at an area not provided with the second projection <NUM> and the first projection <NUM>. Further, since the configuration has the second projection <NUM> and the first projection <NUM>, usage of the conductive adhesive <NUM> can be reduced. Furthermore, the second projection <NUM> can also be used to secure a width of a current path. In particular, when the head part <NUM> sinks into the conductive adhesive <NUM> due to a weight of the connector <NUM>, and the first projection <NUM> and the front surface of the semiconductor element <NUM> are in contact with each other, setting widths (heights) of the first projection <NUM> and the second projection <NUM> to an appropriate value allows providing of the conductive adhesive <NUM> having an appropriate thickness, between the head part <NUM> and the front surfaces of the semiconductor element <NUM>. Note that <FIG> and <FIG> show an aspect in which the second projection <NUM> is not provided.

Further, there is a restriction on an amount of the conductive adhesive <NUM> that can be applied to the front surface of the semiconductor element <NUM>, and a size of the head part <NUM> that can be placed on the front surface of the semiconductor element <NUM>. In this regard, by providing the second projection <NUM> having a size (in an in-plane direction) of an only necessary contact area with the conductive adhesive <NUM>, an appropriate contact area with the conductive adhesive <NUM> can be secured, and the amount of the conductive adhesive <NUM> can be made appropriate.

Further, in an aspect the connector <NUM> is used, as shown in <FIG>, when the base end part <NUM> has the supporting surface <NUM>, even when the head part <NUM> sinks into the conductive adhesive <NUM> due to the weight of the connector <NUM>, the base end part <NUM> can contact with the conductor layer <NUM> with the supporting surface <NUM>, or float in balance on the conductive adhesive <NUM> (before curing). When the supporting surface <NUM> contacts with the conductor layer <NUM>, it is possible to more reliably prevent loss of balance of the connector <NUM>. On the other hand, when the supporting surface <NUM> is floating on the conductive adhesive <NUM>, the base end part <NUM> and the conductor layer <NUM> can be bonded more reliably when the conductive adhesive <NUM> is cured.

In an aspect in which the base end part <NUM> is connected to the conductor layer <NUM> via the conductive adhesive <NUM> such as solder, when adopting an aspect in which the base end part <NUM> has the supporting surface <NUM> and the recess <NUM> that is provided on the peripheral edge of the supporting surface <NUM>, the conductive adhesive <NUM> can be inserted into the recess <NUM>, and a fillet (e.g., a solder fillet) can be easily formed by the conductive adhesive <NUM>. Therefore, cracks and the like can be prevented after the amount of the conductive adhesive <NUM> becomes insufficient and the conductive adhesive <NUM> is cured. In particular, when the connector <NUM> is heavy to an extent where the supporting surface <NUM> contacts with the conductor layer <NUM>, providing such the recess <NUM> is advantageous in that the base end part <NUM> and the conductor layer <NUM> can be bonded by the conductive adhesive <NUM>.

By adopting an aspect in which the length of the supporting surface <NUM> along the first direction is shorter than the length of the second projection <NUM> along the first direction, a size of the base end part <NUM> can be reduced (see <FIG>). In addition, by making the length along the first direction shorter than that of the second projection <NUM>, but longer than that of the first projection <NUM>, the supporting surface <NUM> can prevent loss of balance.

Adopting an aspect in which the first projection <NUM> is positioned at the center in the width direction of the head part <NUM> can prevent inclination of the head part <NUM> in the width direction. In particular, in an aspect in which the head part <NUM> sinks into the conductive adhesive <NUM> due to the weight of the connector <NUM>, and the first projection <NUM> and the front surface of the semiconductor element <NUM> are in contact with each other, the head part <NUM> may incline in the width direction with the first projection <NUM> as the center. In this regard, adopting this aspect can reduce possibility of inclination of the head part <NUM> in the width direction.

When adopting an aspect in which only one first projection <NUM> is provided, it is advantageous in that the conductive adhesive <NUM> can be positioned at an area not provided with the first projection <NUM>, and the conductive adhesive <NUM> can more reliably fix the head part <NUM> to the semiconductor element <NUM>.

In addition, when adopting an aspect in which the first projection <NUM> is positioned at the center position of the second projection <NUM>, it is possible to position the conductive adhesive <NUM> in a well-balanced manner around the first projection <NUM>, and furthermore, it is possible to prevent the head part <NUM> from being inclined with respect to the front surface of the semiconductor element <NUM>.

In a case where the semiconductor element <NUM> has a withstand voltage structure, when there are provided the avoidance parts <NUM> and <NUM> that are integrally formed with the head part <NUM> and to avoid contact with the withstand voltage structure as shown in <FIG> and the like, it is possible to prevent electrical contact in advance between the withstand voltage structure of the semiconductor element <NUM> and the connection body <NUM>.

The first main terminal <NUM> and the front surface sensing terminal <NUM> may be integrally formed with the head part <NUM>, or the first main terminal <NUM> and the second main terminal <NUM> may be integrally formed with the head part <NUM>. In particular, when adopting an aspect in which the first main terminal <NUM> as the first terminal is integrally formed with the front surface sensing terminal <NUM> as the second terminal on an extended line connecting the first terminal and the head part <NUM>, the first main terminal <NUM> and the front surface sensing terminal <NUM> can be utilized as a jig receiver to receive a jig <NUM> (see <FIG>), at a time of manufacturing. Therefore, it is possible to prevent the head part <NUM> from being inclined with respect to the front surface of the semiconductor element <NUM>. However, the present invention is not limited thereto, and it is only necessary that the front surface sensing terminal <NUM> and the connecting part <NUM> extend in a different direction from that of the first main terminal <NUM> as viewed from the head part <NUM>. For example, the front surface sensing terminal <NUM> and the connecting part <NUM>, and the first main terminal <NUM> may extend so as to form <NUM> degrees or an angle greater than <NUM> degrees (obtuse angle).

Hereinafter, a second embodiment disclosing the present invention will be described.

Explanation has been made using the aspect in which the first projection <NUM> has a hemispherical shape in the first embodiment. In the second embodiment, as shown in <FIG> and <FIG>, an aspect is such that a first projection <NUM> has a linear part 41a located on a base side of the first projection <NUM> and having a linear vertical cross-sectional shape, and a hemispherical shape part 41b positioned on a tip end side of the linear part 41a and having a hemispherical or circular-arc vertical cross-sectional shape.

Other configurations are similar to those in the first embodiment. In the second embodiment, same or similar members and the like to the first embodiment are denoted by the same reference numerals, and description thereof is omitted. This embodiment can also provide an effect similar to the effect to be realized by the first embodiment.

In the present embodiment, since the first projection <NUM> has the linear part 41a located on the base side of the first projection <NUM> and having the linear vertical cross-sectional shape, and the hemispherical shape part 41b positioned on the tip end side of the linear part 41a, a diameter of the hemispherical shape part 41b can be reduced. Therefore, even when a head part <NUM> sinks into a conductive adhesive <NUM> and the first projection <NUM> comes into contact with a front surface of a semiconductor element <NUM>, the first projection <NUM> and the front surface of the semiconductor element <NUM> can be brought into contact with each other with a smaller area (point). This can increase an amount of the conductive adhesive <NUM> located between the head part <NUM> and the front surface of the semiconductor element <NUM>, enabling prevention in advance of occurrence of problems such as cracking in the conductive adhesive <NUM> upon curing.

As shown in <FIG>, when adopting an aspect having a tapered shape as the linear part 41a, in which a width decreases toward a tip end, it is possible to increase the conductive adhesive <NUM> on the tip end side. Therefore, it is possible to prevent in advance of occurrence of problems such as cracking in the conductive adhesive <NUM> upon curing, on the tip side close to the semiconductor element <NUM>. Further, since the amount of the conductive adhesive <NUM> can be gradually increased toward the tip end side, the conductive adhesive <NUM> can be evenly and reliably positioned around the first projection <NUM>. Therefore, when the connector <NUM> is adopted, possibility of inclination of the head part <NUM> can be reduced. Note that the linear part 41a has a cylindrical shape in an aspect shown in <FIG>.

Claim 1:
An electronic device comprising:
an insulating substrate (<NUM>);
a conductor layer (<NUM>) provided on the insulating substrate (<NUM>);
an electronic element (<NUM>) provided on the conductor layer (<NUM>);
a connection body (<NUM>) having a head part (<NUM>) connected to a front surface of the electronic element (<NUM>) via a conductive adhesive (<NUM>);
a sealing part (<NUM>) which seals the conductor layer (<NUM>), the electronic element (<NUM>) and the head part (<NUM>), wherein
the head part (<NUM>) has a second projection part (<NUM>) protruding toward a side of the electronic element (<NUM>) from a facing surface facing the front surface of the electronic element (<NUM>), and a first projection part (<NUM>) protruding from the second projection part (<NUM>) toward the side of the electronic element (<NUM>), and
in a state where the first projection part (<NUM>) comes into contact with the front surface of the electronic element (<NUM>), and the conductive adhesive (<NUM>) is bonded to the second projection part (<NUM>) and is bonded to the facing surface of the head part (<NUM>) around the second projection part (<NUM>), the head part (<NUM>) is connected to the front surface of the electronic element (<NUM>),
the first projection part (<NUM>) has a linear part (41a) located on a base side of the first projection part (<NUM>) and having a linear vertical cross-sectional shape, and a hemispherical shape part (41b) positioned on a tip end side of the linear part (41a) and having a hemispherical or circular-arc vertical cross-sectional shape.