Semiconductor modules and power converters

Abstract

To prevent a short circuit between lead frames by making a thickness of solder uniform even when a plurality of lead frames are bonded to one surface of a semiconductor element.SOLUTION: A semiconductor module 1 includes: a plurality of lead frames 5 and 7; a semiconductor element 3 to which the plurality of lead frames 5 and 7 are connected to one surface; a heat dissipation member 9 that is disposed on the other surface of the semiconductor element 3; and a support member 11 that fixes and supports the plurality of lead frames 5 and 7. The support member 11 has: a first support portion 25 that is provided between the plurality of lead frames 5 and 7; and a second support portion 27 that is provided between the plurality of lead frames 5 and 7 and the heat dissipation member.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a semiconductor module and a power conversion device.

Background Art

[0002] Conventionally, in a semiconductor device composed of a semiconductor chip disposed on a substrate and a lead frame joined to an electrode formed on the surface of the semiconductor chip, a semiconductor device for controlling the thickness of solder connecting between the semiconductor chip and the lead frame is disclosed in Patent Document 1. In the semiconductor device disclosed in Patent Document 1, a spacer is provided between the substrate and the lead frame to equalize the thickness of the solder between the semiconductor chip and the substrate and the thickness of the solder between the semiconductor chip and the lead frame.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional semiconductor device, when a plurality of lead frames are joined to one surface of a semiconductor chip, the gap between the lead frames becomes narrow, and it becomes difficult to install a spacer between the lead frames. Therefore, due to the inability to install a spacer, the thickness of the solder cannot be equalized, and there is a problem that a short circuit occurs between the lead frames due to the protruding solder creeping up.

[0005] Therefore, the present invention has been proposed in view of the above circumstances, and an object thereof is to provide a semiconductor module capable of equalizing the thickness of solder and preventing a short circuit between lead frames even when a plurality of lead frames are joined to one surface of a semiconductor element. [Means for solving the problem]

[0006] To solve the above-mentioned problems, a semiconductor module according to one aspect of the present invention comprises a semiconductor element on which a plurality of lead frames are connected to one side, a heat dissipation member disposed on the other side of the semiconductor element, and a support member that fixes and supports the plurality of lead frames. The support member has a first support portion provided between the plurality of lead frames and a second support portion provided between the plurality of lead frames and the heat dissipation member. [Effects of the Invention]

[0007] According to the present invention, even when multiple lead frames are joined to one side of a semiconductor element, the solder thickness can be made uniform to prevent short circuits from occurring between the lead frames. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view along line BB in Figure 2, showing the structure of a semiconductor module according to the first embodiment. [Figure 2] Figure 2 is a cross-sectional view taken along line AA in Figure 1, showing the structure of a semiconductor module according to the first embodiment. [Figure 3A] Figure 3A is a top view showing the structure of a support member constituting a semiconductor module according to the first embodiment. [Figure 3B] Figure 3B is a side view showing the structure of a support member constituting a semiconductor module according to the first embodiment. [Figure 3C] Figure 3C is a side view showing the structure of a support member constituting a semiconductor module according to the first embodiment. [Figure 3D] Figure 3D is a bottom view showing the structure of the support member constituting the semiconductor module according to the first embodiment. [Figure 4] Figure 4 is a side view illustrating the manufacturing method of a semiconductor module according to the first embodiment. [Figure 5]Figure 5 is a side view illustrating the manufacturing method of a semiconductor module according to the first embodiment. [Figure 6] Figure 6 is a side view illustrating the manufacturing method of a semiconductor module according to the first embodiment. [Figure 7] Figure 7 is a cross-sectional view showing the structure of a semiconductor module according to the second embodiment. [Figure 8A] Figure 8A is a top view showing the structure of a support member constituting a semiconductor module according to the second embodiment. [Figure 8B] Figure 8B is a cross-sectional view along the CC line in Figure 8A, showing the structure of the support member constituting the semiconductor module according to the second embodiment. [Figure 9] Figure 9 is a side view illustrating the manufacturing method of a semiconductor module according to the second embodiment. [Figure 10] Figure 10 is a cross-sectional view along the DD line in Figure 11 illustrating the manufacturing method of a semiconductor module according to the second embodiment. [Figure 11] Figure 11 is a top view illustrating the manufacturing method of a semiconductor module according to the second embodiment. [Modes for carrying out the invention]

[0009] [First Embodiment] A first embodiment to which the present invention is applied will be described below with reference to the drawings. In the drawings, the same parts are denoted by the same reference numerals, and detailed descriptions are omitted.

[0010] [Structure of a semiconductor module] The structure of the semiconductor module according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view along line BB in Figure 2 showing the structure of the semiconductor module according to this embodiment, and Figure 2 is a cross-sectional view along line AA in Figure 1 showing the structure of the semiconductor module according to this embodiment.

[0011] The semiconductor module 1 is a power semiconductor module used in power conversion devices such as inverters and converters. As shown in FIGS. 1 and 2, the semiconductor module 1 includes a semiconductor element 3, a first lead frame 5, a second lead frame 7, a heat radiating member 9, a support member 11, and a sealing material 13. Further, the semiconductor element 3 and the first lead frame 5 are joined by a first joining member 17, the semiconductor element 3 and the second lead frame 7 are joined by a second joining member 19, and the semiconductor element 3 and the heat radiating member 9 are joined by a third joining member 21.

[0012] The semiconductor element 3 is a semiconductor chip that functions as a power switching semiconductor element such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or a power rectifying semiconductor element such as a freewheeling diode. The device structure of the semiconductor element 3 is a so-called lateral semiconductor device, and it has a plurality of main electrodes with different potentials on the chip upper surface.

[0013] For example, when the semiconductor element 3 is a MOSFET, it includes a drain electrode, a source electrode, and a gate electrode, and when it is a diode, it includes an anode electrode and a cathode electrode. In addition to this, it may have a control electrode for controlling the amount of current flowing through the semiconductor element 3, and may also have a source electrode for control, an electrode for temperature detection, and an electrode for current detection. The electrodes are mainly composed of a metal material such as aluminum or copper, but a metal such as nickel may be formed on its surface by plating for solder bonding. In this embodiment, a case where the semiconductor element 3 is a MOSFET will be described as an example.

[0014] Also, as the material of the semiconductor element 3, a silicon material is common, but in order to realize a higher-performance semiconductor chip, the semiconductor element 3 may be a wide-bandgap semiconductor such as silicon carbide or gallium nitride.

[0015] The first lead frame 5 is a wiring of metal plates connected to the drain electrode, and the second lead frame 7 is a wiring of metal plates connected to the source electrode. Metal materials such as copper, aluminum, and copper cladding are used. The first lead frame 5 is joined to the semiconductor element 3 by a first bonding member 17, and the second lead frame 7 is joined to the semiconductor element 3 by a second bonding member 19. The first bonding member 17 and the second bonding member 19 are formed from metals such as solder and sintered silver.

[0016] Furthermore, a metal plate material made of copper or copper-molybdenum for stress relief may be provided between the first lead frame 5 and the second lead frame 7 and the semiconductor element 3, and the top and bottom of the plate may be joined with solder or sintered silver. The first lead frame 5 and the second lead frame 7 may be plated with nickel or the like on their surfaces for solder joining. In addition, a resist may be provided to prevent the solder from spreading too much, or holes may be drilled to facilitate resin filling.

[0017] The heat dissipation member 9 is a metal plate formed from a metal material with high thermal conductivity, mainly composed of copper. The heat dissipation member 9 is placed on the underside of the semiconductor element 3 and has the function of dissipating the heat generated by the semiconductor element 3 to a cooler (not shown). However, it may also be formed from a metal material with high thermal conductivity other than copper, such as aluminum or copper-molybdenum. The heat dissipation member 9 is joined to the semiconductor element 3 by a third bonding member 21. The third bonding member 21 is formed from a metal such as solder or sintered silver.

[0018] Furthermore, if the semiconductor element 3 is a vertical semiconductor element, it is necessary to use a material with insulating properties, such as a ceramic substrate, as the heat dissipation member 9. However, in this embodiment, since the semiconductor element 3 is a horizontal semiconductor element, it is not necessary to use a material with insulating properties for the heat dissipation member 9, and high heat dissipation performance can be achieved. In particular, to enhance the heat dissipation effect of the heat dissipation member 9, the heat dissipation performance can be further improved by using a material that is 1 mm or thicker. In this embodiment, as an example, the case in which copper is used for the heat dissipation member 9 will be described.

[0019] The support member 11 fixes the first and second lead frames 5 and 7 and supports them against the heat dissipation member 9. The support member 11 is made of a material that is insulating and can support the first and second lead frames 5 and 7 without melting even when the solder used to join the first and second lead frames 5 and 7 to the semiconductor element 3 is heated during the reflow process. For example, the support member 11 is made of a resin material such as a liquid crystal polymer.

[0020] Here, the structure of the support member 11 will be explained with reference to Figures 3A to 3D. Figure 3A is a top view of the support member 11, Figure 3B is a side view of Figure 3A seen from the X direction, Figure 3C is a side view of Figure 3A seen from the Y direction, and Figure 3D is a bottom view.

[0021] As shown in Figures 3A to 3D, the support member 11 has an upper surface portion 23, a first support portion 25, a second support portion 27, and a side portion 29.

[0022] The upper portion 23 covers a part of the upper surfaces of the first and second lead frames 5 and 7, and together with the first support portion 25, connects and fixes the first lead frame 5 and the second lead frame 7.

[0023] The first support portion 25 is provided between the first lead frame 5 and the second lead frame 7, and connects and fixes the first lead frame 5 and the second lead frame 7. Since the first support portion 25 is provided between the first lead frame 5 and the second lead frame 7, it is possible to prevent short circuits from occurring between the first lead frame 5 and the second lead frame 7.

[0024] In particular, the first support portion 25 is formed over the entire area between the first lead frame 5 and the second lead frame 7, that is, from the top surface to the bottom surface of the first and second lead frames 5 and 7. Therefore, the first support portion 25 can completely prevent solder from creeping up between the first and second lead frames 5 and 7, thus reliably preventing a short circuit from occurring between the first lead frame 5 and the second lead frame 7.

[0025] The second support portion 27 is provided between the first and second lead frames 5 and 7 and the heat dissipation member 9, and maintains a predetermined distance between the first and second lead frames 5 and 7 and the heat dissipation member 9. In other words, the height of the second support portion 27 is set so that the sum of the thicknesses of the semiconductor element 3, the first and second bonding members 17 and 19, and the third bonding member 21 becomes a predetermined value.

[0026] Here, since the height of the semiconductor element 3 remains constant, if a bonding material that can maintain a constant thickness is used for the third bonding member 21, the height of the second support portion 27 is set, and the first and second bonding members 17 and 19 can be formed to the desired thickness. Furthermore, since the two second support portions 27 on the left and right support the first and second lead frames 5 and 7 at the same height, the thickness of the first bonding member 17 and the second bonding member 19 can be formed to a uniform thickness.

[0027] The side portion 29 covers a part of the side surfaces of the first and second lead frames 5 and 7, and together with the top portion 23 and the first support portion 25, connects and fixes the first lead frame 5 and the second lead frame 7. When the semiconductor element 3 is equipped with control electrodes, control wires 31 and 33 are connected to the control electrodes as shown in Figure 2. Therefore, by forming the side portion 29 on the side surfaces of the first and second lead frames 5 and 7 on the side where the control electrodes are provided, it is possible to prevent the solder of the first and second joining members 17 and 19 from overflowing onto the side of the control wires 31 and 33.

[0028] In Figure 2, solder from the first and second joining members 17 and 19 protrudes and creeps upward, forming creeping portions 40 and 42. However, by forming the side portion 29 on the side facing the control wires 31 and 33, the creeping portions 40 and 42 are formed on the opposite side from the control wires 31 and 33. Therefore, it is possible to prevent the control wires 31 and 33 from discharging due to a short circuit between the solder of the first and second joining members 17 and 19 and the control wires 31 and 33.

[0029] The encapsulant 13 is a resin filled around the semiconductor element 3. Specifically, the encapsulant 13 covers the semiconductor element 3 and the support member 11, the entire heat dissipation member 9, and the upper surfaces of the first and second lead frames 5 and 7, thereby covering the entire semiconductor module 1. In Figure 1, the upper and side surfaces of the heat dissipation member 9 are covered with the encapsulant 13, but the lower surface of the heat dissipation member 9 may also be covered with the encapsulant 13. As the encapsulant 13, for example, a resin potting material or gel is used and is formed by transfer molding.

[0030] [Manufacturing method for semiconductor modules] Next, the method for manufacturing a semiconductor module according to this embodiment will be described with reference to Figures 3 to 6. First, as shown in Figures 3A to 3D, the first and second lead frames 5 and 7 and the support member 11 are integrally formed so that the first lead frame 5 and the second lead frame 7 are connected by the support member 11. For example, the first lead frame 5, the second lead frame 7 and the support member 11 can be integrally formed using a method such as transfer molding. At this time, resin and burrs in the areas where solder will be mounted should be removed by polishing or other means as necessary so that solder can be mounted.

[0031] Next, as shown in Figure 4, the semiconductor element 3 and the heat dissipation member 9 are joined with the third joining member 21. Figure 4 is a side view showing the state after joining. The third joining member 21 is solder, and the joining is performed by a reflow process. At this time, in order to prevent the semiconductor element 3 from tilting, the third joining member 21 is a joining material that can maintain a predetermined constant thickness even when the solder used to join the first and second lead frames 5 and 7 to the semiconductor element 3 reaches its melting temperature. For example, solder containing nickel balls can be used. Alternatively, a wire may be used to prevent the semiconductor element 3 from tilting, or copper protrusions may be provided on the heat dissipation member 9.

[0032] Furthermore, as the third bonding member 21, a bonding material such as sintered silver that does not melt when the first bonding member 17 and the second bonding member 19 are joined may be used. In this case, even if a reflow process is performed when joining the first and second lead frames 5 and 7 to the semiconductor element 3, the third bonding member 21 will not melt, so its thickness can be kept constant, and tilting of the semiconductor element 3 can be prevented. Similarly, if a high-melting-point solder is used as the third bonding member 21, it will not melt, so the thickness of the third bonding member 21 can be kept constant, and tilting of the semiconductor element 3 can be prevented.

[0033] Once the heat dissipation member 9 is joined to the semiconductor element 3, the first lead frame 5 and the semiconductor element 3 are then joined with the first joining member 17, and the second lead frame 7 and the semiconductor element 3 are joined with the second joining member 19. As shown in Figure 5, the member in which the first and second lead frames 5 and 7 and the support member 11 are integrally formed is placed on top of the member in which the semiconductor element 3 and the heat dissipation member 9 are joined. Figure 5 is a side view showing the state after installation.

[0034] At this time, a first joining member 17 is placed at the location where the first lead frame 5 and the semiconductor element 3 are joined, and a second joining member 19 is placed at the location where the second lead frame 7 and the semiconductor element 3 are joined. The first and second joining members 17 and 19 are solder, and by using a generous amount of solder, a gap 60 is created as shown in Figure 5, causing the support member 11 to float away from the heat dissipation member 9.

[0035] After this, when the temperature inside the reflow oven is raised to the solder melting temperature while a load is applied from above, the solder melts. As a result, as shown in Figure 6, the support member 11 sinks until it contacts the heat dissipation member 9, so that the distance between the first and second lead frames 5 and 7 and the heat dissipation member 9 can be set to the height of the second support part 27. Figure 6 is a side view showing the state after the first and second lead frames 5 and 7 have been joined.

[0036] Furthermore, since the amount of solder used for the first and second joining members 17 and 19 is generous, the solder will overflow during joining and spread up onto the sides of the first and second lead frames 5 and 7. However, in this embodiment, as shown in Figure 2, the sides of the first and second lead frames 5 and 7 on the side where the control wires 31 and 33 are provided are covered by the side portion 29, and the first support portion 25 is also provided between the first and second lead frames 5 and 7.

[0037] Therefore, the solder creeps up the opposite side of the control wires 31 and 33, forming creeping portions 40 and 42 and solidifying. This not only prevents the solder from short-circuiting between the first and second lead frames 5 and 7, but also prevents the solder from short-circuiting and discharging from the control wires 31 and 33.

[0038] Once the first and second lead frames 5 and 7 are connected to the semiconductor element 3, control wires 31 and 33, formed from metal wires such as aluminum, copper, gold, or silver, are bonded to the gate electrode and control source electrode. After this, a encapsulating material 13 is formed by transfer molding or resin potting, completing the semiconductor module 1 according to this embodiment. Furthermore, the semiconductor module 1 may be attached to the cooler with grease or the like, or it may be bonded to the cooler using a bonding material.

[0039] [Effects of the First Embodiment] As described in detail above, the semiconductor module 1 according to this embodiment comprises a plurality of lead frames 5 and 7, a semiconductor element 3, a heat dissipation member 9, and a support member 11 that fixes and supports the plurality of lead frames 5 and 7. The support member 11 has a first support portion 25 provided between the plurality of lead frames 5 and 7, and a second support portion 27 provided between the plurality of lead frames 5 and 7 and the heat dissipation member 9. This makes it possible to make the solder thickness uniform and prevent the lead frames from short-circuiting, even when the plurality of lead frames 5 and 7 are joined to one side of the semiconductor element 3.

[0040] In particular, in this embodiment, since the first support portion 25 is provided between the first lead frame 5 and the second lead frame 7, short circuits between the first lead frame 5 and the second lead frame 7 can be prevented. Also, since the second support portion 27 is provided between the first and second lead frames 5 and 7 and the heat dissipation member 9, the distance between the first and second lead frames 5 and 7 and the heat dissipation member 9 can be maintained at a predetermined distance. As a result, the solder thickness of the first and second joining members 17 and 19 can be formed to a uniform thickness. Furthermore, in this embodiment, the distance between the first and second lead frames 5 and 7 can be reduced, and the bonding area per chip can be increased, thereby improving heat dissipation performance and reducing resistance and parasitic inductance. Thus, according to the semiconductor module 1 of this embodiment, a power module with high reliability and high performance can be realized.

[0041] Furthermore, in the semiconductor module 1 according to this embodiment, the first support portion 25 is formed from the upper surface to the lower surface of the multiple lead frames 5 and 7. This completely prevents solder from creeping up between the first and second lead frames 5 and 7. Therefore, a short circuit between the first lead frame 5 and the second lead frame 7 can be reliably prevented.

[0042] Furthermore, in the semiconductor module 1 according to this embodiment, the semiconductor element 3 has multiple main electrodes on one side to which multiple lead frames 5 and 7 are connected. In a lateral semiconductor device with multiple main electrodes on one side, the distance between the lead frames becomes smaller. Therefore, by applying the semiconductor module 1 according to this embodiment to a lateral semiconductor device, even if the distance between the first and second lead frames 5 and 7 becomes smaller, short circuits between the first and second lead frames 5 and 7 can be prevented.

[0043] Furthermore, in the semiconductor module 1 according to this embodiment, the joining member that joins the semiconductor element 3 and the multiple lead frames 5 and 7 is solder. This allows the semiconductor element 3 and the multiple lead frames 5 and 7 to be easily joined by performing a reflow process.

[0044] Furthermore, in the semiconductor module 1 according to this embodiment, the support member 11 is made of a resin material capable of supporting the multiple lead frames 5, 7 at the melting temperature of the solder that joins the semiconductor element 3 and the multiple lead frames 5, 7. As a result, the first and second lead frames 5, 7 can be supported at a predetermined height even after a reflow process, and the thickness of the solder connecting the semiconductor element 3 and the first and second lead frames 5, 7 can be made uniform.

[0045] Furthermore, in the semiconductor module 1 according to this embodiment, the bonding member that joins the semiconductor element 3 and the heat dissipation member 9 is a bonding material that can maintain a predetermined constant thickness at the melting temperature of the solder that joins the semiconductor element 3 and the plurality of lead frames 5 and 7. As a result, the thickness of the solder can be controlled to a constant value, thereby suppressing the tilt of the semiconductor element 3. Moreover, the thickness of the first and second bonding members 17 and 19 can be formed to a predetermined thickness.

[0046] Furthermore, in the semiconductor module 1 according to this embodiment, the semiconductor element 3 is equipped with control electrodes, and the support member 11 has a side portion 29 formed on the side of the multiple lead frames 5, 7 on the side where the control electrodes are provided. This prevents solder from creeping up to the side where the control electrodes are provided, thereby preventing the control wires 31, 33 from short-circuiting with the solder and causing a discharge.

[0047] Furthermore, in the semiconductor module 1 according to this embodiment, the semiconductor element 3 is made of a wide-bandgap semiconductor. With a wide-bandgap semiconductor, the chip area is smaller, making it easier for short circuits to occur between the first and second lead frames 5 and 7. Therefore, by applying the semiconductor module 1 according to this embodiment to a wide-bandgap semiconductor, it is possible to more effectively prevent short circuits between the lead frames 5 and 7, even if the chip area is reduced.

[0048] Furthermore, in this embodiment, a power converter equipped with a semiconductor module 1 is configured. As a result, since the power converter is configured using a semiconductor module 1 which has high heat dissipation performance and high reliability, a power converter with high heat dissipation performance and high reliability can be realized.

[0049] [Second Embodiment] A second embodiment to which the present invention is applied will be described below with reference to the drawings. In the drawings, the same parts are denoted by the same reference numerals, and detailed descriptions are omitted.

[0050] Figure 7 is a cross-sectional view showing the structure of the semiconductor module 1 according to this embodiment. As shown in Figure 7, the semiconductor module 1 according to this embodiment differs from the first embodiment in that a through hole 51 is formed in the portion of the first lead frame 5 that is connected to the semiconductor element 3. Similarly, a through hole 53 is formed in the portion of the second lead frame 7 that is connected to the semiconductor element 3. The first and second joining members 17 and 19 flow into these through holes 51 and 53 when the first and second lead frames 5 and 7 are joined to the semiconductor element 3.

[0051] In the first embodiment, when joining the first and second lead frames 5 and 7, the first and second joining members 17 and 19 protruded from the sides of the first and second lead frames 5 and 7, forming upward-growing portions 40 and 42.

[0052] However, in this embodiment, since through holes 51 and 53 are formed, the first and second joining members 17 and 19 will not protrude from the sides of the first and second lead frames 5 and 7. Therefore, it is possible to prevent the control wires 31 and 33 from discharging due to short-circuiting with the solder of the first and second joining members 17 and 19.

[0053] The structure of the support member 11 will now be described with reference to Figures 8A and 8B. Figure 8A is a top view showing the structure of the support member 11, and Figure 8B is a cross-sectional view along line CC in Figure 8A. As shown in Figures 8A and 8B, the support member 11 has a first support portion 25 and a second support portion 27.

[0054] The first support portion 25 is provided between the first lead frame 5 and the second lead frame 7, and connects and fixes the first lead frame 5 and the second lead frame 7. Since the first support portion 25 is provided between the first lead frame 5 and the second lead frame 7, it can prevent short circuits between the first lead frame 5 and the second lead frame 7.

[0055] The second support portion 27 is provided between the first and second lead frames 5 and 7 and the heat dissipation member 9, and maintains a predetermined distance between the first and second lead frames 5 and 7 and the heat dissipation member 9. In other words, the height of the second support portion 27 is set so that the sum of the thicknesses of the semiconductor element 3, the first and second bonding members 17 and 19, and the third bonding member 21 becomes a predetermined value.

[0056] [Manufacturing method for semiconductor modules] Next, the manufacturing method of the semiconductor module according to this embodiment will be described with reference to Figures 8 to 11. First, as shown in Figures 8A and 8B, the first and second lead frames 5 and 7 and the support member 11 are integrally formed. For example, the first lead frame 5, the second lead frame 7, and the support member 11 can be integrally formed using a method such as transfer molding. At this time, in order to enable soldering, any resin or burrs in the areas where solder will be mounted should be removed by polishing or other means as needed.

[0057] Next, the semiconductor element 3 and the heat dissipation member 9 are joined with the third joining member 21, similar to Figure 4 of the first embodiment. Once the heat dissipation member 9 is joined to the semiconductor element 3, the first lead frame 5 and the semiconductor element 3 are then joined with the first joining member 17, and the second lead frame 7 and the semiconductor element 3 are joined with the second joining member 19. As shown in Figure 9, the member in which the first and second lead frames 5 and 7 and the support member 11 are integrally formed is placed on top of the member in which the semiconductor element 3 and the heat dissipation member 9 are joined. Figure 9 is a side view showing the state after installation.

[0058] At this time, a first joining member 17 is placed at the location where the first lead frame 5 and the semiconductor element 3 are joined, and a second joining member 19 is placed at the location where the second lead frame 7 and the semiconductor element 3 are joined. The first and second joining members 17 and 19 are solder, and by using a generous amount of solder, a gap 60 is created as shown in Figure 9, causing the support member 11 to float away from the heat dissipation member 9.

[0059] After this, when a load is applied from above and the temperature inside the reflow oven is raised to the solder melting temperature, the solder melts. As a result, as shown in Figure 10, the support member 11 sinks until it contacts the heat dissipation member 9, so that the distance between the first and second lead frames 5 and 7 and the heat dissipation member 9 can be set to the height of the second support part 27. Figure 10 is a cross-sectional view showing the state after the first and second lead frames 5 and 7 have been joined.

[0060] Furthermore, since a generous amount of solder is used for the first and second joining members 17 and 19, as shown in Figures 10 and 11, the solder flows into the through holes 51 and 53 during joining. Therefore, the solder does not spill out onto the sides of the first and second lead frames 5 and 7, and thus the control wires 31 and 33 can be prevented from discharging by short-circuiting with the solder of the first and second joining members 17 and 19.

[0061] Once the first and second lead frames 5 and 7 are connected to the semiconductor element 3, control wires 31 and 33, formed from metal wires such as aluminum, copper, gold, or silver, are bonded to the gate electrode and control source electrode. After this, a encapsulating material 13 is formed by transfer molding or resin potting, completing the semiconductor module 1 according to this embodiment. Furthermore, the semiconductor module 1 may be attached to the cooler with grease or the like, or it may be bonded to the cooler using a bonding material.

[0062] [Effects of the second embodiment] As described in detail above, in the semiconductor module 1 according to this embodiment, through holes 51 and 53 are formed in the portions of the multiple lead frames 5 and 7 that are joined to the semiconductor elements 3. As a result, the solder of the first and second joining members 17 and 19 flows into the through holes 51 and 53, preventing the solder from short-circuiting with the control wires 31 and 33 and causing the control wires 31 and 33 to discharge.

[0063] The embodiments described above are merely examples of the present invention. Therefore, the present invention is not limited to the embodiments described above, and various modifications are possible in forms other than those described above, as long as they do not depart from the technical spirit of the present invention, depending on the design and other factors. [Explanation of Symbols]

[0064] 1. Semiconductor module 3 Semiconductor elements 5. First lead frame 7. Second lead frame 9 Heat dissipation component 11 Support Member 13. Sealing material 17. First Joining Member 19. Second Joining Member 21 Third Joining Member 23 Top part 25 1st support part 27 Second support part 29 Side part 31, 33 Control wires 40, 42 Climbing section 51, 53 Through holes 60 gap

Claims

1. Multiple lead frames, A semiconductor element in which the plurality of lead frames are connected to one side, A heat dissipation member disposed on the other side of the semiconductor element, The system includes a support member that fixes and supports the plurality of lead frames, The aforementioned support member is A first support portion provided between the plurality of lead frames, A semiconductor module having a plurality of lead frames and a second support portion provided between the heat dissipation member.

2. The semiconductor module according to claim 1, wherein the first support portion is formed from the upper surface to the lower surface of the lead frame in the region between the plurality of lead frames.

3. The semiconductor module according to claim 1, wherein the semiconductor element has a plurality of main electrodes on one of its surfaces to which the plurality of lead frames are connected.

4. The semiconductor module according to claim 1, wherein the joining member for joining the semiconductor element and the plurality of lead frames is solder.

5. The semiconductor module according to claim 4, wherein the support member is made of a resin material capable of supporting the plurality of lead frames at the melting temperature of the solder used to join the semiconductor element and the plurality of lead frames.

6. The semiconductor module according to claim 4, wherein the bonding member for joining the semiconductor element and the heat dissipation member is a bonding material capable of maintaining a predetermined constant thickness at the melting temperature of the solder used to join the semiconductor element and the plurality of lead frames.

7. The semiconductor module according to any one of claims 1 to 6, wherein the semiconductor element comprises a control electrode for controlling the amount of current flowing within the semiconductor element, and the support member has a side portion formed on the side of the plurality of lead frames on the side on which the control electrode is provided.

8. The semiconductor module according to any one of claims 1 to 6, wherein the plurality of lead frames have through holes formed in the portion that is joined to the semiconductor element.

9. The semiconductor module according to any one of claims 1 to 6, wherein the semiconductor element is a wide-bandgap semiconductor.

10. A power conversion device comprising a semiconductor module according to any one of claims 1 to 6.

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