WO2020213167A1

WO2020213167A1 - Semiconductor device, and manufacturing method for same

Info

Publication number: WO2020213167A1
Application number: PCT/JP2019/016873
Authority: WO
Inventors: 祐貴河村; 亮輔安部
Original assignee: 三菱電機株式会社
Priority date: 2019-04-19
Filing date: 2019-04-19
Publication date: 2020-10-22

Abstract

A highly reliable semiconductor device can be obtained. This semiconductor device is provided with a semiconductor element (11), a busbar (12), a connection conductor (13) and a wire (14). The semiconductor element (11) includes an electrode (21) formed on a first surface (11a). The busbar (12) is arranged on the electrode (21). The connection conductor (13) connects the electrode (21) and the busbar (12). The wire (14) surrounds the connection conductor (13) and contacts the end of the electrode (21). The wire (14) is fixed to the semiconductor element (11) in at least one region outside of the electrode (21). The wire is configured such that the distance between the surface of the wire (14) and the surface of the electrode (21) increases from the area of connection between the wire (14) and the electrode (21) towards the center of the electrode (21). At least part of the outer periphery of the connection conductor (13) contacts the aforementioned surface of the wire (14) and the aforementioned surface of the electrode (21).

Description

Semiconductor devices and their manufacturing methods

The present invention relates to a semiconductor device and a method for manufacturing the same.

Conventionally, vertical semiconductor devices suitable for high current applications are known. In the vertical semiconductor element, electrodes are arranged on both the front and back surfaces of the semiconductor element. Conventionally, wire bonding using a metal wire has been applied to electrical wiring with an electrode on the front surface side.

In the connection by wire bonding, it is necessary to join a large number of wires to one electrode as the current capacity increases. Further, when a temperature cycle load is applied to the semiconductor element, thermal stress is generated due to the difference in linear expansion coefficient between different materials at the joint between the electrode and the wire. In this case, since the cross-sectional area of one wire is relatively small, the wire may be broken.

Therefore, in recent years, instead of wire bonding connection, semiconductor devices for joining a copper bus bar and an electrode of a semiconductor element using a solder material have been mass-produced. With such a structure, effects such as space saving of electrical wiring, increase of joint strength by increasing the joint area between the wiring and the electrode, and increase of current density by reducing resistance inside the wiring can be expected.

On the other hand, in such a semiconductor device, stress may be concentrated on the end of the electrode connected to the bus bar in the semiconductor element due to the temperature cycle load, and damage such as cracks may occur in the electrode.

In order to prevent such damage to the electrodes, for example, Japanese Patent Application Laid-Open No. 2009-147123 discloses a semiconductor device having a fillet shape confined inward at an intermediate portion in the thickness direction at a solder joint portion between an electrode and a bus bar. Has been done.

In Japanese Patent Application Laid-Open No. 2009-147123, when the electrodes of a semiconductor element and the bus bar are joined by solder, the following process is carried out in order to form a fillet shape confined inward at the end face of the solder. First, a refractory metal wire is arranged so as to surround the plate-shaped solder pellets arranged on the electrode. By carrying out the solder reflow process, the molten solder flows along the surface of the wire and then the solder is solidified. Then, the wire is removed.

JP-A-2009-147123

In the process described above, the wire is not fixed to the electrode of the semiconductor element. Therefore, the wires may be displaced during the transfer of the semiconductor element before the reflow process and during the reflow process, and as a result, the position of the solder may be displaced, or the shape of the end face of the solder may be different from the target shape. When the solder is misaligned or has a poor shape in this way, it becomes difficult to suppress damage to the electrodes of the semiconductor element, and as a result, the reliability of the semiconductor device is lowered.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a highly reliable semiconductor device.

A semiconductor device according to the present disclosure includes a semiconductor element, a bus bar, a connecting conductor, and a wire. The semiconductor element has a first surface. The semiconductor element includes an electrode formed on the first surface. Busbars are placed on the electrodes. The connecting conductor is arranged between the electrode and the bus bar. The connecting conductor connects the electrode and the bus bar. The wire surrounds the connecting conductor and touches the end of the electrode on the first surface. The wire is fixed to the semiconductor element in at least one region other than the electrode. The wire is configured so that the distance between the surface of the wire and the surface of the electrode increases from the connection between the wire and the electrode toward the center of the electrode. At least a part of the outer peripheral portion of the connecting conductor is in contact with the surface of the wire and the surface of the electrode.

The method for manufacturing a semiconductor device according to the present disclosure includes a step of preparing a semiconductor element having a first surface. The semiconductor element includes an electrode formed on the first surface. The method for manufacturing a semiconductor device further includes a step of fixing a wire on the first surface of the semiconductor element. In the fixing step, the wire is fixed to the semiconductor element so as to surround the electrode and contact the end of the electrode. The method for manufacturing a semiconductor device further includes a step of arranging a plate-shaped or paste-shaped connecting conductor on an electrode surrounded by wires, a step of arranging a bus bar on a connecting conductor, and a step of connecting. In the connecting process, the connecting conductor is heated and melted, and the bus bar and the electrode are connected by the connecting conductor.

According to the above, a highly reliable semiconductor device can be obtained.

It is a plan schematic diagram of the semiconductor device which concerns on Embodiment 1. FIG. It is sectional drawing of the line segment II-II of FIG. It is sectional drawing of the line segment III-III of FIG. It is a schematic diagram for demonstrating the structure of the semiconductor device shown in FIG. It is a plan schematic diagram for demonstrating the manufacturing method of the semiconductor device shown in FIG. It is a plan schematic diagram for demonstrating the manufacturing method of the semiconductor device shown in FIG. It is a plan schematic diagram for demonstrating the manufacturing method of the semiconductor device shown in FIG. It is sectional drawing of the semiconductor device which concerns on Embodiment 2. FIG. It is a schematic diagram for demonstrating the structure of the semiconductor device which concerns on Embodiment 3. It is sectional drawing of the semiconductor device which concerns on Embodiment 4. FIG. It is sectional drawing which shows the 1st modification of the semiconductor device which concerns on Embodiment 4. FIG. It is sectional drawing which shows the 2nd modification of the semiconductor device which concerns on Embodiment 4. FIG. It is a schematic diagram for demonstrating the structure of the semiconductor device which concerns on Embodiment 5. It is a schematic diagram for demonstrating the structure of the semiconductor device which concerns on Embodiment 7. It is a schematic diagram which shows the 1st modification of the semiconductor device which concerns on Embodiment 7. It is a schematic diagram which shows the 2nd modification of the semiconductor device which concerns on Embodiment 7. It is a schematic diagram which shows the 3rd modification of the semiconductor device which concerns on Embodiment 7. It is a schematic diagram which shows the 4th modification of the semiconductor device which concerns on Embodiment 7. It is a schematic diagram for demonstrating the structure of the semiconductor device which concerns on Embodiment 8. It is a schematic diagram which shows the 1st modification of the semiconductor device which concerns on Embodiment 8. It is a schematic diagram which shows the 2nd modification of the semiconductor device which concerns on Embodiment 8. It is a schematic diagram which shows the 3rd modification of the semiconductor device which concerns on Embodiment 8.

Hereinafter, embodiments of the present invention will be described. The same reference number will be assigned to the same configuration, and the description will not be repeated.

Embodiment 1.
<Semiconductor device configuration>
FIG. 1 is a schematic plan view of the semiconductor device according to the first embodiment. FIG. 2 is a schematic cross-sectional view of the line segment II-II of FIG. FIG. 3 is a schematic cross-sectional view taken along the line segments III-III of FIG. FIG. 4 is a schematic diagram for explaining the configuration of the semiconductor device shown in FIG. The semiconductor device according to the present embodiment will be described with reference to FIGS. 1 to 4.

The semiconductor device shown in FIGS. 1 to 4 includes a semiconductor element 11, a bus bar 12, a connecting conductor 13, and a wire 14. The semiconductor element 11 has a first surface 11a. The semiconductor element 11 includes an electrode 21 formed on the first surface 11a and a convex portion 22. A plurality of convex portions 22 are arranged so as to surround the electrodes 21. In the semiconductor device shown in FIGS. 1 to 4, four convex portions 22 are arranged so as to surround the electrodes 21. The convex portions 22 are arranged on the outer periphery of the electrode 21 at intervals. As shown in FIG. 4, the planar shape of the electrode 21 is a quadrangular shape with curved corners. The convex portion 22 is arranged in a region where the extension lines of the linear adjacent sides in the planar shape of the electrode 21 intersect.

The electrode 21 may be composed of a single conductor, but may include a plurality of layers as shown in FIG. As shown in FIG. 2, for example, the electrode 21 includes a first layer 16 which is a solder bonding electrode in contact with the first surface 11a and a second layer 15 which is a solder bonding plating film laminated on the first layer 16. including. The first layer 16 may be made of any conductor, but may be made of, for example, aluminum. The second layer 15 may be made of a material for improving the bondability with the connecting conductor 13. For example, when the bonded conductor is lead-free solder, a nickel plating film may be used as the second layer 15.

The convex portion 22 may have the same configuration as the electrode 21. That is, the convex portion 22 includes a first layer 18 which is an electrode for wire bonding in contact with the first surface 11a, and a second layer 17 which is a plating film for wire bonding laminated on the first layer 18. The first layer 18 may be made of the same material as the first layer 16 of the electrode 21. The second layer 17 may be made of the same material as the second layer 15 of the electrode 21.

The bus bar 12 is arranged on the electrode 21. The connecting conductor 13 connects the electrode 21 and the bus bar 12. The wire 14 includes

linear wire members

14a and 14b. The

wire members

14a and 14b are arranged on the first surface 11a so as to surround the connecting conductor 13. The

wire members

14a and 14b are in contact with the end of the electrode 21 as shown in FIG.

The wire 14 is fixed to the convex portion 22 arranged at a position adjacent to the electrode 21. Specifically, the wire 14 is fixed to the semiconductor element 11 at a convex portion 22 which is at least one region other than the electrode 21. As shown in FIG. 2, two

wire members

14a and 14b are fixed to one convex portion 22. Any method can be used for fixing the wire 14 to the convex portion 22, and for example, an ultrasonic joining method can be used. On the other hand, although the wire 14 is in contact with the surface of the electrode 21, it is not directly fixed by using an ultrasonic joining method or the like.

The wire 14 is arranged so that the distance between the surface of the wire 14 and the surface of the electrode 21 increases from the connection portion (non-fixed contact portion) between the wire 14 and the electrode 21 toward the central portion of the electrode 21. Is configured. Specifically, as shown in FIGS. 2 and 3, the cross-sectional shape of the wire 14 in the direction orthogonal to the extending direction is circular. At least a part of the outer peripheral portion of the connecting conductor 13 is in contact with the surface of the wire 14 and the surface of the electrode 21 as shown in FIG. That is, the outer peripheral portion of the connecting conductor 13 has an inclined surface whose thickness becomes thinner toward the outside. The inclined surface is along the surface of the wire 14.

<Manufacturing method of semiconductor devices>
5 to 7 are schematic plan views for explaining the manufacturing method of the semiconductor device shown in FIG. 1. The method for manufacturing the semiconductor device shown in FIG. 1 will be described with reference to FIGS. 4 and 5 to 7 described above.

In the method for manufacturing a semiconductor device shown in FIG. 1, first, as shown in FIG. 4, a step of preparing a semiconductor element 11 having a first surface 11a is carried out. In the preparation step, the semiconductor element 11 includes an electrode 21 and a convex portion 22 formed on the first surface 11a. The electrode 21 and the convex portion 22 are arranged at independent positions on the first surface 11a. As shown in FIG. 4, the convex portion 22 is arranged on the outer peripheral portion of the electrode 21. If there is one or more convex portions 22, they may be separated and arranged at a plurality of locations.

Next, as shown in FIG. 5, a step of fixing the wire 14 on the first surface 11a of the semiconductor element 11 is performed. In the fixing step, the wire 14 is fixed to the semiconductor element 11 so as to surround the electrode 21 and contact the end of the electrode 21. The wire 14 is fixed to the convex portion 22 by an arbitrary fixing method. For example, the wire 14 is fixed to the convex portion 22 by using an ultrasonic joining method. When fixing the wire 14, the wire 14 is arranged along the outer peripheral portion of the electrode 21. When a plurality of

wire members

14a and 14b constituting the wire 14 are arranged, the

wire members

14a and 14b may be arranged so as to cover the outer peripheral portion of the electrode 21 as the whole wire 14. The wire 14 and the convex portion 22 may be bonded and fixed by another method instead of ultrasonic bonding. One or more wires 14 may be joined to each of the convex portions 22 having independent positions.

Next, as shown in FIG. 6, a step of arranging the plate-shaped or paste-shaped connecting conductor 13 on the electrode 21 surrounded by the wire 14 is carried out. As the connecting conductor 13, for example, lead-free solder can be used. At this time, the connecting conductor 13 may not be in direct contact with the wire 14, but may be in contact with the wire 14. The connecting conductor 13 is arranged on the upper surface of the electrode 21 surrounded by the wire 14, and the bus bar 12 is arranged on the upper surface of the connecting conductor 13.

Next, as shown in FIG. 7, a step of arranging the bus bar 12 on the connecting conductor 13 is carried out. At this time, it is preferable that the bus bar 12 comes into contact with the connecting conductor 13. That is, it is preferable that the height from the surface of the electrode 21 to the top of the connecting conductor 13 is higher than the height from the surface of the electrode 21 to the top of the wire 14.

Next, carry out the connecting process. In the connecting step, which is a reflow step, the connecting conductor 13 is heated and melted, and the bus bar 12 and the electrode 21 are connected by the connecting conductor 13. Specifically, the semiconductor element 11 in which the bus bar 12 is laminated and arranged on the connecting conductor 13 as described above is arranged in the reflow furnace. By heating the entire semiconductor element in the reflow furnace, the connecting conductor 13 is heated and melted. The melting point of the wire 14 is higher than the melting point of the plate-shaped or paste-shaped connecting conductor 13. Therefore, the wire 14 itself does not melt during the reflow process. When the connecting conductor 13 melts, the melted connecting conductor 13 wets and spreads on the surface of the electrode 21, and comes into contact with the surface of the wire 14 located on the end of the electrode 21. As a result, the angle of the end portion of the connecting conductor 13 in contact with the upper surface of the electrode 21 becomes smaller along the surface shape of the wire 14. After that, the semiconductor device including the semiconductor element 11 is taken out from the reflow furnace and cooled. As a result, the melted connecting conductor 13 can be solidified, and the electrode 21 and the bus bar 12 can be joined by the connecting conductor 13.

<Effect>
To summarize the characteristic configurations of the semiconductor device described above, the semiconductor device according to the present disclosure includes a semiconductor element 11, a bus bar 12, a connecting conductor 13, and a wire 14. The semiconductor element 11 has a first surface 11a. The semiconductor element 11 includes an electrode 21 formed on the first surface 11a. The bus bar 12 is arranged on the electrode 21. The connecting conductor 13 is arranged between the electrode 21 and the bus bar 12. The connecting conductor 13 connects the electrode 21 and the bus bar 12. The wire 14 surrounds the connecting conductor 13 and contacts the end of the electrode 21 on the first surface 11a. The wire 14 is fixed to the semiconductor element 11 in at least one region other than the electrode 21. The wire 14 is configured so that the distance between the surface of the wire 14 and the surface of the electrode 21 increases from the connection portion between the wire 14 and the electrode 21 toward the central portion of the electrode 21. At least a part of the outer peripheral portion of the connecting conductor 13 is in contact with the surface of the wire 14 and the surface of the electrode 21.

In this way, the shape of the outer peripheral portion of the connecting conductor 13 can be made into a shape in which the thickness of the connecting conductor 13 becomes thinner as it approaches the outer peripheral end portion on the surface of the electrode 21. That is, the angle formed by the end surface of the connecting conductor 13 with the surface of the electrode 21 can be reduced. As a result, the thermal stress generated at the end of the connecting conductor 13 due to the thermal cycle load can be reduced. Therefore, when a thermal cycle load is applied to the semiconductor element 11, stress concentration at the end of the electrode 21 can be suppressed, and damage to the electrode 21 can be suppressed.

Further, the wire 14 fixed to the semiconductor element 11 can suppress the occurrence of a problem that the pellets (for example, solder pellets) of the conductor to be the connecting conductor 13 are displaced from the electrode 21 in the manufacturing process of the semiconductor device. Further, by adjusting the surface shape of the wire 14, the shape of the outer peripheral portion of the connecting conductor 13 in contact with the surface of the wire 14 can be controlled as a result. Further, since the wire 14 is fixed to the semiconductor element 11 in a region different from that of the electrode 21, the wire 14 is caused by a step of fixing the wire 14 to the semiconductor element 11 (for example, an ultrasonic joining step) or a thermal cycle load. Even if the connection portion between the semiconductor element 11 and the semiconductor element 11 is damaged, the damage does not adversely affect the electrode 21.

In the above semiconductor device, the material constituting the bus bar 12 is one selected from the group consisting of copper (Cu), copper alloy, and copper clad material. In this case, sufficient conductivity can be ensured in the bus bar connected to the electrode 21 of the semiconductor element 11.

In the semiconductor device, the wire 14 includes a plurality of

wire members

14a and 14b arranged so as to surround the connecting conductor 13. The plurality of

wire members

14a and 14b are fixed to the semiconductor element 11, respectively. The shapes of the

wire members

14a and 14b seen from the direction perpendicular to the first surface are linear or curved.

In this case, a wire 14 having an arbitrary planar shape can be obtained by combining a plurality of linear or

curved wire members

14a and 14b according to the planar shape of the electrode 21 or the connecting conductor 13.

In the above semiconductor device, the cross-sectional shape of the wire 14 in the direction perpendicular to the extending direction is any one selected from the group consisting of a circular shape, a semicircular shape, an elliptical shape, and a trapezoidal shape. In this case, by appropriately selecting the cross-sectional shape of the wire 14, the angle formed by the end face of the connecting conductor 13 and the surface of the electrode 21 can be arbitrarily set, or the shape of the end face of the connecting conductor 13 can be linear or arbitrary. It can be a curved surface with a curvature of.

In the above semiconductor device, the material constituting the wire 14 includes a conductor typified by a metal such as aluminum (Al). By using the material constituting the wire 14 as the conductor in this way, the wire 14 can also be used as a part of the conductor connecting the electrode 21 and the bus bar 12.

In the above semiconductor device, the semiconductor element 11 includes a convex portion 22 arranged at a position adjacent to the electrode 21 on the first surface 11a. The wire 14 is fixed to the convex portion 22. In this case, the wire 14 can be easily fixed to the semiconductor element 11 by fixing a part of the wire 14 to the convex portion 22. The height of the convex portion 22 from the first surface 11a is preferably equal to the height of the electrode 21 from the first surface 11a. The convex portion 22 may be made of the same material as the electrode 21. The convex portion 22 may be formed of the same layer as the electrode 21.

In the semiconductor device, the convex portion 22 includes a first convex portion 22 and a second convex portion 22 arranged at a distance from the first convex portion 22. One or more places on the wire 14 are fixed to the first convex portion 22 and the second convex portion 22, respectively. In this case, since the wire 14 can be fixed to the semiconductor element 11 at the first convex portion 22 and the second convex portion 22, the wire 14 can be reliably fixed to the semiconductor element 11.

The method for manufacturing a semiconductor device according to the present disclosure includes a step of preparing a semiconductor element 11 having a first surface 11a. The semiconductor element 11 includes an electrode 21 formed on the first surface 11a. The method for manufacturing a semiconductor device further includes a step of fixing the wire 14 on the first surface 11a of the semiconductor element 11 as shown in FIG. In the fixing step, the wire 14 is fixed to the semiconductor element 11 so as to surround the electrode 21 and contact the end of the electrode 21. Further, a method for manufacturing a semiconductor device includes a step of arranging a plate-shaped or paste-shaped connecting conductor 13 on an electrode 21 surrounded by wires 14 as shown in FIG. 6, and a step of arranging the connecting conductor 13 on the connecting conductor 13 as shown in FIG. A step of arranging the bus bar 12 and a step of connecting the bus bar 12 are provided. In the connecting step, the connecting conductor 13 is heated and melted, and the bus bar 12 and the electrode 21 are connected by the connecting conductor 13.

By doing so, the semiconductor device according to the present disclosure can be obtained. Further, when the semiconductor element 11 is transported to the reflow furnace for heating the connecting conductor 13 in the connecting step, or when the connecting conductor 13 is heated in the reflow furnace, the connecting conductor 13 before melting (for example, a plate, pellets or Consider a case where a stress is applied to the paste-like connecting conductor) in the direction toward the outside of the electrode 21. In this case, since the movement of the connecting conductor 13 is restricted by the wire 14, the connecting conductor 13 can be maintained in a state of being arranged on the electrode 21 even when the stress is applied. As a result, it is possible to prevent the connecting conductor 13 from being displaced.

In the process of fixing the semiconductor device, the wire 14 is fixed to the semiconductor element 11 in at least one region other than the electrode 21. In this case, since the wire 14 is fixed to the semiconductor element 11 in a region different from the electrode 21, it is assumed that the connection portion between the wire 14 and the semiconductor element 11 is damaged due to the fixing process or the thermal cycle load. However, the damage does not adversely affect the electrode 21.

Embodiment 2.
<Semiconductor device configuration>
FIG. 8 is a schematic cross-sectional view of the semiconductor device according to the second embodiment. Note that FIG. 8 corresponds to FIG. The semiconductor device shown in FIG. 8 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the bus bar 12 is different from that of the semiconductor device shown in FIGS. 1 to 3. .. That is, in the semiconductor device shown in FIG. 8, the bus bar 12 has a laminated structure in which the first member 12a and the second member 12b are laminated. For example, the second member 12b may be a layer made of copper, and the first member 12a may be any conductor. The second member 12b may be a clad layer made of copper in which a copper layer is connected to the first member 12a. That is, the bus bar 12 may be a copper clad material. Further, copper or a copper alloy may be used as the material constituting the bus bar 12. The structure of the bus bar 12 is not limited to the two-layer structure shown in FIG. 8, and a three-layer or more laminated structure may be adopted.

<Effect>
To summarize the characteristic configurations of the above-mentioned semiconductor device, in the above-mentioned semiconductor device, the material constituting the bus bar 12 is one selected from the group consisting of copper (Cu), a copper alloy, and a copper clad material. In this case, sufficient conductivity can be ensured in the bus bar 12 connected to the electrode 21 of the semiconductor element 11.

Embodiment 3.
<Semiconductor device configuration>
FIG. 9 is a schematic diagram for explaining the configuration of the semiconductor device according to the third embodiment. Note that FIG. 9 corresponds to FIG. The semiconductor device shown in FIG. 9 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the wire 14 is different from that of the semiconductor device shown in FIGS. 1 to 3. .. That is, in the semiconductor device shown in FIG. 9, the wire member 14c in which the wire 14 is bent is included. More specifically, the wire 14 is composed of two bent wire members 14c. The wire member 14c is arranged at a position where it overlaps the outer circumference of the electrode 21 in a plan view. From a different point of view, the end of one wire member 14c is arranged to face the end of the other wire member 14c. The end of one wire member 14c and the end of the other wire member 14c are fixed to the same convex portion 22. The bent portion of the wire member 14c does not have to be particularly fixed to the semiconductor element 11. The connecting conductor 13 is arranged in the region surrounded by the wire member 14c. The cross-sectional shape of the wire member 14c in the direction perpendicular to the extending direction is, for example, a circular shape.

<Effect>
In the semiconductor device, the wire 14 includes a plurality of wire members 14c arranged so as to surround the connecting conductor 13. Each of the plurality of wire members 14c is fixed to the semiconductor element 11. The shape of the wire member 14c seen from the direction perpendicular to the first surface 11a is curved.

As described above, when the curved wire member 14c is used, one wire member 14c can be arranged so as to be located on the outer peripheral portion of the electrode 21 facing at least two directions in the plan view. As shown in FIG. 5, the number of wire members 14c used can be reduced as compared with the case where all

linear wire members

14a and 14b are used. As a result, the process of arranging the wire members 14c can be simplified as compared with the case of using the

linear wire members

14a and 14b.

Embodiment 4.
<Structure and effect of semiconductor devices>
FIG. 10 is a schematic cross-sectional view of the semiconductor device according to the fourth embodiment. FIG. 11 is a schematic cross-sectional view showing a first modification of the semiconductor device according to the fourth embodiment. FIG. 12 is a schematic cross-sectional view showing a second modification of the semiconductor device according to the fourth embodiment. 10 to 12 correspond to FIG.

The semiconductor device shown in FIG. 10 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the wire 14 is different from that of the semiconductor device shown in FIGS. 1 to 3. .. That is, in the semiconductor device shown in FIG. 10, the cross-sectional shape of the wire member 14d constituting the wire 14 in the direction orthogonal to the extending direction is a semicircular shape. The cross-sectional shape of the wire member 14d is curved on the electrode 21 side and linear on the bus bar 12 side. The end of the connecting conductor 13 is in contact with the wire 14. In this case, the contact angle with respect to the surface of the electrode 21 at the end of the connecting conductor 13 can be made smaller than that of the semiconductor device shown in FIG. Here, the smaller the angle at the end of the cross section of the connecting conductor 13 in the direction perpendicular to the surface of the electrode 21, the more the stress concentration at the end of the connecting conductor 13 on the upper surface side of the second layer 15 of the electrode 21. Can be suppressed. Therefore, it is possible to reduce the thermal stress generated in the electrode 21 (particularly the first layer 16) when the temperature cycle load is applied to the semiconductor element 11. As a result, it is possible to prevent the electrode 21 from being damaged or damaged.

The semiconductor device shown in FIG. 11 basically has the same configuration as the semiconductor device shown in FIG. 10, but the structure of the wire 14 is different from that of the semiconductor device shown in FIG. That is, in the semiconductor device shown in FIG. 11, the cross-sectional shape of the wire member 14d constituting the wire 14 in the direction orthogonal to the extending direction is elliptical. In the semiconductor device shown in FIG. 11, the cross-sectional shape of the wire member 14e constituting the wire 14 is an elliptical shape having a long axis extending in a direction along the surface of the electrode 21. In this case as well, the same effect as that of the semiconductor device shown in FIG. 10 can be obtained.

The semiconductor device shown in FIG. 12 basically has the same configuration as the semiconductor device shown in FIG. 10, but the structure of the wire 14 is different from that of the semiconductor device shown in FIG. That is, in the semiconductor device shown in FIG. 12, the cross-sectional shape of the wire member 14d constituting the wire 14 in the direction orthogonal to the extending direction is trapezoidal. In the semiconductor device shown in FIG. 12, the cross-sectional shape of the wire member 14f constituting the wire 14 has a side extending obliquely with respect to the surface of the electrode 21 on the connecting conductor 13 side and the surface side of the electrode 21. In this case, by reducing the angle of the side of the electrode 21 with respect to the surface (for example, 30 ° or less, preferably 20 ° or less, more preferably 10 ° or less), the same effect as that of the semiconductor device shown in FIG. 10 can be obtained. be able to.

Further, in the cross-sectional shape of the wire member 14f, the side facing the surface of the electrode 21 extends in the direction along the surface of the electrode 21. In the cross-sectional shape of the wire member 14f, the side facing the bus bar 12 extends in the direction along the lower surface of the bus bar 12. Therefore, the adhesion between the contact portion between the wire member 14f and the surface of the electrode 21 and the contact portion between the wire member 14f and the bus bar 12 can be improved.

To summarize the characteristic configurations of the above-mentioned semiconductor device, in the above-mentioned semiconductor device, the cross-sectional shape in the direction perpendicular to the extending direction of the wire 14 is a group consisting of a circular shape, a semicircular shape, an elliptical shape, and a trapezoidal shape. It is any one selected from. In this case, by appropriately selecting the cross-sectional shape of the wire 14, the angle formed by the end face of the connecting conductor 13 and the surface of the electrode 21 can be set to an arbitrary angle, or the shape of the end face of the connecting conductor 13 can be linear or arbitrary. It can be a curved surface with a curvature of.

Embodiment 5.
<Structure and effect of semiconductor devices>
The semiconductor device according to the present embodiment basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the wire 14 is different from that of the semiconductor device shown in FIGS. 1 to 3. There is. That is, in the semiconductor device according to the present embodiment, a metal wire such as copper or gold is used as the wire 14 instead of an aluminum wire. The melting point of the material constituting the wire 14 is higher than the melting point of the connecting conductor 13. In this case, the connecting conductor 13 melts during the reflow process, but the wire 14 does not. Therefore, similarly to the semiconductor devices shown in FIGS. 1 to 3, the angle of the end portion of the connecting conductor 13 with respect to the upper surface of the electrode 21 can be reduced.

To summarize the characteristic configuration of the above-mentioned semiconductor device, in the above-mentioned semiconductor device, the material constituting the wire 14 is any one selected from aluminum (Al), copper (Cu), and gold (Au). Including. By making the material constituting the wire 14 a conductive metal in this way, the wire 14 can also be used as a part of the conductor connecting the electrode 21 and the bus bar 12. Further, by selecting a material having a melting point higher than the melting point of the connecting conductor 13 as the material constituting the wire 14, the shape of the end portion of the connecting conductor 13 can be made to follow the shape of the wire 14 when the connecting conductor 13 is reflowed. it can.

Embodiment 6.
<Semiconductor device configuration>
FIG. 13 is a schematic diagram for explaining the configuration of the semiconductor device according to the fifth embodiment. Note that FIG. 13 corresponds to FIG. The semiconductor device shown in FIG. 13 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the wire 14 and the arrangement of the convex portions 22 are shown in FIGS. 1 to 3. It is different from semiconductor devices. That is, in the semiconductor device shown in FIG. 13, the wire 14 includes a wire member 14 g in which the wire 14 is bent in an annular shape. Only one convex portion 22 is arranged at a position separated from the outer circumference of the electrode 21. Both ends of the wire member 14g are arranged on one convex portion 22. Both ends of the wire member 14g are fixed to the same convex portion 22. Any method can be used for fixing the wire member 14 g to the convex portion 22, but for example, an ultrasonic joining method may be used. The wire member 14g has an annular shape along the outer circumference of the upper surface of the electrode 21. The wire member 14g is in contact with the outer periphery of the upper surface of the electrode 21, but is not fixed.

<Effect>
To summarize the characteristic configuration of the semiconductor device, in the semiconductor device, the wire 14 is a single wire member 14g that surrounds the outer circumference of the connecting conductor 13 (see FIG. 3). In this case, the wire 14 can be installed along the outer circumference of the electrode 21 so that the arrangement of the connecting conductor 13 is restricted only by arranging one wire member 14g. Therefore, the step of arranging the wire 14 can be simplified.

Embodiment 7.
<Structure and effect of semiconductor devices>
FIG. 14 is a schematic diagram for explaining the configuration of the semiconductor device according to the seventh embodiment. 15 to 18 are schematic views showing first to fourth modified examples of the semiconductor device according to the seventh embodiment. 14 to 18 correspond to FIG. 4.

The semiconductor device shown in FIG. 14 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the convex portion 22 is different from that of the semiconductor device shown in FIGS. 1 to 3. There is. That is, in the semiconductor device shown in FIG. 14, the planar shape of the convex portion 22 is an elliptical shape. The planar shape of the convex portion 22 in the semiconductor device shown in FIG. 14 is an elliptical shape in which the minor axis is arranged so as to face the center of the electrode 21. From a different point of view, the planar shape of the convex portion 22 is an elliptical shape arranged so that the long axis extends in the direction along the outer circumference of the electrode 21.

The semiconductor device shown in FIG. 15 basically has the same configuration as the semiconductor device shown in FIG. 14, but the structure of the convex portion 22 is different from that of the semiconductor device shown in FIG. That is, in the semiconductor device shown in FIG. 15, the planar shape of the convex portion 22 is a triangular shape which is an example of a polygonal shape. The side of the convex portion 22 facing the electrode 21 in the planar shape extends in a direction intersecting the line segment toward the center of the electrode 21. The two sides of the convex portion 22 other than the side facing the electrode 21 extend along the two linear sides in the planar shape of the electrode 21.

The semiconductor device shown in FIG. 16 basically has the same configuration as the semiconductor device shown in FIG. 14, but the structure of the convex portion 22 is different from that of the semiconductor device shown in FIG. That is, in the semiconductor device shown in FIG. 16, the planar shape of the convex portion 22 is a shape in which the corners of the polygon are curved. The planar shape of the convex portion 22 shown in FIG. 16 is specifically a shape in which the corner portions are curved in a rectangular shape. The side of the convex portion 22 facing the electrode 21 in the planar shape extends in a direction intersecting the line segment toward the center of the electrode 21.

The semiconductor device shown in FIG. 17 basically has the same configuration as the semiconductor device shown in FIG. 14, but the structure of the convex portion 22 is different from that of the semiconductor device shown in FIG. That is, in the semiconductor device shown in FIG. 17, the convex portion 22 is formed so as to surround the outer periphery of the electrode 21. The convex portion 22 has an annular shape, and the outer line on the inner peripheral side in the planar shape of the convex portion 22 extends along the outer line at intervals from the outer line of the planar shape of the electrode 21. The outer line on the outer peripheral side in the planar shape of the convex portion 22 is a quadrangular shape.

The semiconductor device shown in FIG. 18 basically has the same configuration as the semiconductor device shown in FIG. 17, but the structure of the convex portion 22 is different from that of the semiconductor device shown in FIG. That is, in the semiconductor device shown in FIG. 18, the convex portion 22 is formed so as to surround the outer circumference of the electrode 21 in an annular shape. The outer line on the outer peripheral side of the planar shape of the convex portion 22 extends along the outer line of the planar shape of the electrode 21. The convex portion 22 extends in an annular shape, and the width of the convex portion 22 in the direction perpendicular to the extending direction of the convex portion 22 may be substantially the same in the circumferential direction.

To summarize the characteristic configurations of the above-mentioned semiconductor device, in the above-mentioned semiconductor device, the planar shape of the convex portion 22 is a circular shape shown in FIG. 4, an elliptical shape shown in FIG. 14, a polygonal shape shown in FIG. 15, and FIG. The shape in which the corners of the polygon shown in FIG. 17 are curved, the shape in which the outer periphery of the electrode 21 shown in FIG. 17 is circularly surrounded and the outermost circumference is polygonal, and the outer periphery of the electrode 21 shown in FIG. It is one selected from a group consisting of a polygon whose outermost circumference is a polygon and whose corners are curved. In this case, the planar shape of the convex portion 22 can be appropriately selected according to the shape of the wire 14 and the planar shape of the electrode 21.

Embodiment 8.
<Structure and effect of semiconductor devices>
FIG. 19 is a schematic diagram for explaining the configuration of the semiconductor device according to the eighth embodiment. 20 to 22 are schematic views showing first to third modified examples of the semiconductor device according to the eighth embodiment. Note that FIGS. 19 to 22 correspond to FIG.

The semiconductor device shown in FIG. 19 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the electrode 21 is different from that of the semiconductor device shown in FIGS. 1 to 3. .. That is, in the semiconductor device shown in FIG. 19, the planar shape of the electrode 21 is rectangular and the corners are curved. The planar shape of the electrode 21 shown in FIG. 19 has a larger ratio of the length of the long side to the short side than that of the electrode 21 shown in FIG.

The semiconductor device shown in FIG. 20 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the electrode 21 is different from that of the semiconductor device shown in FIGS. 1 to 3. .. That is, in the semiconductor device shown in FIG. 20, the planar shape of the electrode 21 is an octagonal shape, which is an example of a polygonal shape. The convex portion 22 is arranged at a position facing one side in the planar shape of the electrode 21. The length of the side of the electrode 21 with which the convex portion 22 faces is shorter than the length of the other side of the electrode 21 with which the convex portion 22 does not face.

The semiconductor device shown in FIG. 21 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the electrode 21 is different from that of the semiconductor device shown in FIGS. 1 to 3. .. That is, in the semiconductor device shown in FIG. 21, the planar shape of the electrode 21 is circular. The plurality of convex portions 22 are arranged at positions symmetrical with respect to the center of the electrode 21.

The semiconductor device shown in FIG. 22 basically has the same configuration as the semiconductor device shown in FIGS. 1 to 3, but the structure of the electrode 21 is different from that of the semiconductor device shown in FIGS. 1 to 3. .. That is, in the semiconductor device shown in FIG. 22, the planar shape of the electrode 21 is elliptical. The plurality of convex portions 22 are arranged at positions line-symmetrical with respect to each of the major axis and the minor axis in the planar shape of the electrode 21.

To summarize the characteristic configurations of the above-mentioned semiconductor device, in the above-mentioned semiconductor device, the planar shape of the electrode 21 is a circular shape shown in FIG. 21, a polygonal shape shown in FIG. 20, and a corner portion of the polygon shown in FIG. It is one selected from the group consisting of curved shapes. In this case, the configuration according to the present disclosure can be applied to the semiconductor element 11 having electrodes 21 having various shapes.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. As long as there is no contradiction, at least two of the embodiments disclosed this time may be combined. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope of the claims.

11 Semiconductor element, 11a 1st surface, 12 Bus bar, 12a 1st member, 12b 2nd member, 13 Connecting conductor, 14 Wire, 14a-14g Wire member, 15, 17 2nd layer, 16, 18 1st layer, 21 Electrode, 22 convex part.

Claims

A semiconductor device having a first surface is provided, the semiconductor element includes an electrode formed on the first surface, and further.
The bus bar arranged on the electrode and
A connecting conductor arranged between the electrode and the bus bar and connecting the electrode and the bus bar,
On the first surface, a wire that surrounds the connecting conductor and is in contact with the end of the electrode is provided.
The wire is fixed to the semiconductor element in at least one region other than the electrode.
The wire is configured so that the distance between the surface of the wire and the surface of the electrode increases from the connection portion between the wire and the electrode toward the central portion of the electrode.
A semiconductor device in which at least a part of the outer peripheral portion of the connecting conductor is in contact with the surface of the wire and the surface of the electrode.
The semiconductor device according to claim 1, wherein the material constituting the bus bar is one selected from the group consisting of copper, a copper alloy, and a copper clad material.
The wire comprises a plurality of wire members arranged so as to surround the connecting conductor.
The plurality of wire members are fixed to the semiconductor element, respectively, and
The semiconductor device according to claim 1 or 2, wherein the shape of the wire member when viewed from a direction perpendicular to the first surface is linear or curved.
Claims 1 to 3, wherein the cross-sectional shape in the direction perpendicular to the extending direction of the wire is any one selected from the group consisting of a circular shape, a semicircular shape, an elliptical shape, and a trapezoidal shape. The semiconductor device according to any one item.
The semiconductor device according to any one of claims 1 to 4, wherein the material constituting the wire includes any one selected from aluminum, copper, and gold.
The semiconductor element includes a convex portion arranged at a position adjacent to the electrode on the first surface.
The semiconductor device according to any one of claims 1 to 5, wherein the wire is fixed to the convex portion.
The convex portion includes a first convex portion and a second convex portion arranged at a distance from the first convex portion.
The semiconductor device according to claim 6, wherein one or more places of the wire are fixed to the first convex portion and the second convex portion, respectively.
The planar shape of the convex portion is a circular shape, an elliptical shape, a polygonal shape, a shape in which the corners of the polygon are curved, a shape that surrounds the outer circumference of the electrode in an annular shape and the outermost circumference is a polygon, and the electrode. The semiconductor according to claim 6 or 7, which is one selected from the group consisting of a shape that encloses the outer circumference of the surface in a ring shape and has a polygonal outermost circumference and curved corners of the polygon. apparatus.
According to any one of claims 1 to 8, the planar shape of the electrode is one selected from the group consisting of a circular shape, a polygonal shape, and a shape in which the corners of the polygon are curved. The described semiconductor device.
A step of preparing a semiconductor element having a first surface is provided, the semiconductor element includes an electrode formed on the first surface, and further.
A step of fixing a wire on the first surface of the semiconductor element is provided.
In the fixing step, the wire is fixed to the semiconductor element so as to surround the electrode and be in contact with the end of the electrode, and further.
A step of arranging a plate-shaped or paste-shaped connecting conductor on the electrode surrounded by the wire, and
The process of arranging the bus bar on the connecting conductor and
A method for manufacturing a semiconductor device, comprising a step of heating and melting the connecting conductor and connecting the bus bar and the electrode by the connecting conductor.