Semiconductor device

Abstract

A semiconductor device according to the present disclosure comprises: a heat dissipator; a case that is provided on the heat dissipator and houses a semiconductor chip; a main terminal that is electrically connected to the semiconductor chip and provided on the case; a nut portion that is embedded in the heat dissipator; and a conductive screw that is provided so as to traverse the main terminal and the case and engage the nut portion, wherein at least one of the heat dissipator and the nut portion is insulative.

Description

Semiconductor device

[0001] This disclosure relates to a semiconductor device.

[0002] Patent Document 1 discloses a heating element cooling device. This heating element cooling device includes a metal cooling tank that stores an insulating refrigerant liquid. A bolt is passed through a bolt hole of an electrical component having a heating element. This bolt is screwed into a female screw portion of the cooling tank.

[0003] Japanese Patent Application Laid-Open No. 2008-85052

[0004] In Patent Document 1, the tip of the bolt is electrically connected to the cooling tank. However, in Patent Document 1, insulation between the bolt and the cooling tank is not considered. For example, when the bolt is electrically connected to a terminal of an electrical component, there is a risk that the terminal and the cooling tank are not insulated.

[0005] An object of this disclosure is to obtain a semiconductor device capable of insulating a main terminal of a semiconductor chip and a heat sink.

[0006] The semiconductor device according to the first disclosure includes a heat sink, a case provided on the heat sink for housing a semiconductor chip, a main terminal provided on the case and electrically connected to the semiconductor chip, a nut portion embedded in the heat sink, and a conductive screw provided so as to penetrate the main terminal and the case and engage with the nut portion, and at least one of the heat sink or the nut portion is insulating.

[0007] The semiconductor device according to the second disclosure includes an insulating heat sink, a case provided on the heat sink for housing a semiconductor chip, a main terminal provided on the case and electrically connected to the semiconductor chip, a conductive screw penetrating the main terminal and inserted into the case, and a spring connecting the screw and the heat sink.

[0008] The semiconductor device according to the third disclosure comprises a conductive heat sink, a case provided on the heat sink for housing a semiconductor chip, a main terminal electrically connected to the semiconductor chip and provided on the case, and a screw that penetrates the main terminal and is inserted into the case, wherein the screw has a conductive portion on its upper end adjacent to the main terminal and an insulating portion on its lower end, and the main terminal and the heat sink are insulated by the insulating portion.

[0009] In the semiconductor device described in the first disclosure, at least one of the heat sink or the nut portion is insulating. This allows for insulation between the main terminals of the semiconductor chip and the heat sink. In the semiconductor device described in the second disclosure, the heat sink is insulating. This allows for insulation between the main terminals of the semiconductor chip and the heat sink. In the semiconductor device described in the third disclosure, the insulating portion of the screw allows for insulation between the main terminals of the semiconductor chip and the heat sink.

[0010] This is a plan view of a semiconductor device according to Embodiment 1. This is a plan view showing the internal configuration of a semiconductor device according to Embodiment 1. This is a cross-sectional view obtained by cutting Figure 1 along the line A-B. This is a plan view of a semiconductor device according to Embodiment 2. This is a cross-sectional view obtained by cutting Figure 4 along the line A-B. This is a cross-sectional view of a semiconductor device according to Embodiment 3. This is a cross-sectional view of a semiconductor device according to Embodiment 4. This is a cross-sectional view of a semiconductor device according to Embodiment 5. This is a cross-sectional view of a semiconductor device according to Embodiment 6. This is a cross-sectional view of a semiconductor device according to Embodiment 7. This is a cross-sectional view of a semiconductor device according to a comparative example.

[0011] The semiconductor devices according to each embodiment will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repetition of the description may be omitted.

[0012] Embodiment 1. Figure 1 is a plan view of the semiconductor device 100 according to Embodiment 1. Figure 2 is a plan view showing the internal configuration of the semiconductor device 100 according to Embodiment 1. Figure 3 is a cross-sectional view obtained by cutting Figure 1 along the line A-B. The semiconductor device 100 comprises a water-cooled jacket 10 which is a heat sink, and a case 14 provided on the water-cooled jacket 10. The case 14 is insulating. The case 14 houses semiconductor chips 24 and 26.

[0013] In this embodiment, the water-cooling jacket 10 is insulating and is made of, for example, resin. The water-cooling jacket 10 contains a coolant liquid 40. The coolant liquid 40 is insulating. A base plate 12 is provided between the case 14 and the water-cooling jacket 10. The base plate 12 is also called a heat sink. The base plate 12 is, for example, conductive. Pin fins 13 extending from the base plate 12 are in contact with the coolant liquid 40. The case 14 is bonded to the upper surface of the base plate 12. An insulating substrate is mounted on the base plate 12. Semiconductor chips 24 and 26 are soldered to patterns formed on the insulating substrate.

[0014] The semiconductor chip 24 is, for example, an IGBT (Insulated Gate Bipolar Transistor), and the semiconductor chip 26 is, for example, a diode. The semiconductor device 100 is, for example, a power control semiconductor device. Figure 1 shows an example in which the semiconductor device 100 is a 6-in-1 automotive power module. The rated current of the semiconductor device 100 is, for example, 300A to 600A, and the rated voltage is, for example, 600V to 1200V.

[0015] Multiple main terminals 16 are provided on the case 14. The main terminals 16 are made of, for example, copper. The main terminals 16 are, for example, inserted into the case 14. Each main terminal 16 is electrically connected to one of the multiple semiconductor chips 24, 26 via an inner electrode 28. The main terminals 16 are terminals for supplying current to the semiconductor chips 24, 26. If the semiconductor chip 24 is an IGBT, the main terminal 16 becomes either the emitter electrode or the collector electrode.

[0016] The case 14 is provided with multiple signal terminals 19. Each signal terminal 19 is electrically connected to one of the multiple semiconductor chips 24, 26 via an aluminum wire. The signal terminals 19 are terminals for inputting control signals to turn the semiconductor chips 24, 26 on and off. If the semiconductor chip 24 is an IGBT, the signal terminal 19 becomes the gate electrode. The inside of the case 14 is sealed with resin 22.

[0017] A nut portion 11 is embedded in the water cooling jacket 10. The nut portion 11 is also called an insert nut. The nut portion 11 may be part of the water cooling jacket 10. The nut portion 11 may be a separate part from the water cooling jacket 10. The nut portion 11 is, for example, conductive and made of metal. A screw 20 is provided so as to penetrate the bus bar 18, the main terminal 16, the case 14, and the base plate 12. The screw 20 is conductive and made of metal. The screw 20 is, for example, M5 to M6 size. The screw 20 engages with the nut portion 11. The main terminal 16 and the bus bar 18 are fastened together by the screw 20 and the nut portion 11. The main terminal 16 is electrically connected to the outside by the bus bar 18.

[0018] Specifically, the main terminal 16, bus bar 18, and water cooling jacket 10 are fastened together with the fastening holes of the bus bar 18, the main terminal 16, the case 14, and the nut portion 11 all overlapping. As a result, the threaded portion at the tip of the screw 20 makes thermal contact with the water cooling jacket 10 via the nut portion 11. In Figure 3, the flow of heat from the main terminal 16 is indicated by arrows. Heat from the semiconductor chips 24 and 26 reaches the water cooling jacket 10 via the main terminal 16, bus bar 18, screw 20, and nut portion 11. This allows the heat to be dissipated by the coolant liquid 40 or the vapor of the coolant liquid 40 contained in the water cooling jacket 10.

[0019] Figure 11 is a cross-sectional view of a semiconductor device 800 according to a comparative example. In the semiconductor device 800 according to the comparative example, the nut portion 811 is provided on the case 14. The screw 20 does not reach the base plate 12. There is a gap between the tip of the screw 20 and the case. In such a structure, there is a problem that the main terminal 16 generates heat due to the contact resistance between the main terminal 16 and the busbar 18 through which a large current flows.

[0020] In contrast, in this embodiment, the screw 20 engages with a nut portion 11 provided on the water cooling jacket 10. This ensures a contact area between the screw 20 and the nut portion 11. Therefore, heat from the main terminal 16 can be efficiently transferred to the water cooling jacket 10. Due to the high heat dissipation, for example, a snubber capacitor with a low heat resistance temperature can be mounted near the main terminal 16.

[0021] Furthermore, the water-cooling jacket 10 in this embodiment is insulating. Therefore, it is possible to insulate the main terminal 16, through which a large current flows, from the water-cooling jacket 10. Thus, by contact between the conductive screw 20 and the conductive nut portion 11, it is possible to insulate the main terminal 16 and busbar 18 from the water-cooling jacket 10 while enabling fastening of the components and efficient heat dissipation.

[0022] The conductive nut portion 11 and the conductive base plate 12 do not come into contact with each other in order to maintain insulation. Furthermore, the case 14 has a protrusion 15 that extends between the base plate 12 and the screw 20. In other words, the base plate 12 and the screw 20 are separated by a part of the case 14. This allows for insulation between the main terminal 16 and the base plate 12. In this way, proper insulation can be achieved between the components. Additionally, a conventional metal screw can be used as the screw 20. Therefore, parts are readily available, and manufacturing costs can be reduced.

[0023] Furthermore, in this embodiment, the busbar 18, main terminal 16, case 14, and water cooling jacket 10 can be fastened together with screws 20. Therefore, it is not necessary to provide separate screws for fastening the busbar 18, main terminal 16, and case 14, and for fastening the case 14 and water cooling jacket 10. Consequently, the semiconductor device 100 can be miniaturized. In addition, the number of parts and processing steps can be reduced.

[0024] The configuration of the semiconductor device 100 is not limited to that shown in Figure 1-3. For example, the semiconductor device 100 only needs to have at least one semiconductor chip. Also, the types of semiconductor chips 24 and 26 are not limited. For example, the semiconductor chips 24 and 26 may be formed from wide-bandgap semiconductors. Wide-bandgap semiconductors are, for example, silicon carbide, gallium nitride-based materials, or diamond. Furthermore, the heat sink only needs to be insulating and is not limited to the water-cooling jacket 10.

[0025] The modifications described above can be appropriately applied to the semiconductor device according to the following embodiments. Since the semiconductor device according to the following embodiments has many similarities with Embodiment 1, the explanation will focus on the differences from Embodiment 1.

[0026] Embodiment 2. Figure 4 is a plan view of the semiconductor device 200 according to Embodiment 2. Figure 5 is a cross-sectional view obtained by cutting Figure 4 along the line A-B. In this embodiment, a nut portion 211 is provided on the case 14. The nut portion 211 is, for example, conductive. The nut portion 211 is also called an insert nut. The nut portion 211 may be part of the case 14, or it may be a separate part from the case 14.

[0027] A conductive screw 20 passes through the main terminal 16 and is inserted into the case 14. The screw 20 is provided to pass through the busbar 18, the main terminal 16, the case 14, and the base plate 12. The main terminal 16, the busbar 18, and the case 14 are fastened together by the screw 20 and the nut portion 211. The case 14 and the water cooling jacket 10 are fastened together by a screw 230. A collar 231 is provided between the screw 230 and the case 14. The screw 20 and the insulating water cooling jacket 10 are connected by a spring 232. The spring 232 is, for example, a metal leaf spring. The other configurations are the same as those of Embodiment 1.

[0028] In this embodiment, the screw 20 and the water-cooling jacket 10 are connected via a spring 232. Therefore, heat from the main terminal 16 can be efficiently transferred to the water-cooling jacket 10. In particular, variations in the thickness or warping of the material can be absorbed by the spring 232. This ensures a secure connection between the tip of the screw 20 and the water-cooling jacket 10 via the spring 232.

[0029] Furthermore, the water-cooling jacket 10 in this embodiment is insulating. Therefore, it is possible to insulate the main terminal 16, through which a large current flows, from the water-cooling jacket 10. Thus, while enabling fastening of components and efficient heat dissipation, it is possible to insulate the main terminal 16 and busbar 18 from the water-cooling jacket 10.

[0030] Embodiment 3. Figure 6 is a cross-sectional view of the semiconductor device 300 according to Embodiment 3. In this embodiment, the conductive base plate 12 corresponds to the heat sink. The water-cooling jacket 310 is also conductive and is made of, for example, an aluminum alloy. The base plate 12 and the water-cooling jacket 310 may be considered together as the heat sink. The nut portion 311 embedded in the base plate 12 is insulating and is made of, for example, a resin. The nut portion 311 is provided, for example, from the upper end of the case 14 or the lower surface of the main terminal 16 to the upper surface of the water-cooling jacket 310.

[0031] In this embodiment, the screw 20 engages with the nut portion 311, causing the screw 20 to make thermal contact with the base plate 12 via the nut portion 311. Therefore, heat from the main terminal 16 can be efficiently transferred to the base plate 12 and the water cooling jacket 310. Furthermore, because the nut portion 311 is insulating, it is possible to insulate the main terminal 16, through which a large current flows, from the base plate 12 and the water cooling jacket 310. Thus, insulation can be provided between the main terminal 16 and the busbar 18 and the heat sink while enabling fastening of the components and efficient heat dissipation. In addition, the fastening force can be improved by tightening the main terminal 16 and the busbar 18 between the nut portion 311 and the screw head of the screw 20.

[0032] Embodiment 4. Figure 7 is a cross-sectional view of a semiconductor device 400 according to Embodiment 4. The semiconductor device 400 includes a conductive water-cooling jacket 310 as a conductive heat sink, and a conductive base plate 12 provided between the water-cooling jacket 310 and the case 14. The screw 420 passes through the main terminal 16 and is inserted into the case 14. The screw 420 is provided so as to pass through the bus bar 18, the main terminal 16, and the case 14.

[0033] The screw 420 has a conductive portion 420a on its upper end adjacent to the main terminal 16 and an insulating portion 420b on its lower end. The screw 20 is also called a current-insulating screw. The insulating portion 420b insulates the main terminal 16 from the base plate 12 and the water-cooling jacket 310. The base plate 12 has a female threaded portion 411 that engages with the screw 420. The insulating portion 420b is formed on the portion of the screw 420 that engages with the female threaded portion 411. The threaded portion of the insulating portion 420b may be made of resin.

[0034] In this embodiment, the insulating portion 420b of the screw 420 engages with the threaded portion 411 provided on the base plate 12, causing the screw 420 to be in thermal contact with the base plate 12. Therefore, heat from the main terminal 16 can be efficiently transferred to the base plate 12 and the water cooling jacket 310. Furthermore, the insulating portion 420b of the screw 420 provides insulation between the main terminal 16, through which a large current flows, and the base plate 12 and the water cooling jacket 310. Thus, insulation can be provided between the main terminal 16 and the busbar 18 and the heat sink while enabling fastening of the components and efficient heat dissipation.

[0035] Furthermore, by forming the water-cooling jacket 310 from an aluminum alloy, heat dissipation can be further improved. Also, by providing a female threaded portion 411 as part of the base plate 12 instead of the nut portion in Embodiments 1-3, the number of parts can be reduced. Therefore, miniaturization and reduction of processing steps become possible.

[0036] Embodiment 5. Figure 8 is a cross-sectional view of the semiconductor device 500 according to Embodiment 5. This embodiment differs from Embodiment 4 in that a female threaded portion 511 that engages with a screw 520 is formed in the water-cooling jacket 310. The screw 520 is provided so as to penetrate the bus bar 18, the main terminal 16, the case 14, and the base plate 12. The screw 520 has a conductive portion 520a on the upper end side adjacent to the main terminal 16 and an insulating portion 520b on the lower end side. The insulating portion 520b is formed, for example, from the portion of the screw 520 adjacent to the base plate 12 to the portion that engages with the female threaded portion 511. The other configurations are the same as those of Embodiment 4.

[0037] In this embodiment as well, the main terminal 16 and busbar 18 can be insulated from the heat sink while enabling fastening of the components and efficient heat dissipation. Also, similar to Embodiment 1, the busbar 18, main terminal 16, case 14 and water cooling jacket 310 can be fastened with screws 20. For this reason, for example, the screws 230 that fasten the case 14 and the water cooling jacket 310 can be omitted. Consequently, the semiconductor device 500 can be miniaturized, and the number of parts and processing steps can be reduced.

[0038] Embodiment 6. Figure 9 is a cross-sectional view of a semiconductor device 600 according to Embodiment 6. In this embodiment, the screw 620 passes through the busbar 18 and the main terminal 16 and is inserted into the case 14. The main terminal 16, the busbar 18 and the case 14 are fastened together by the screw 620 and the nut portion 211 provided on the case 14. The screw 620 has a conductive portion 620a on the upper end side adjacent to the main terminal 16 and an insulating portion 620b on the lower end side. A metal spring 232 connects the insulating portion 620b of the screw 620 to a conductive heat sink. The spring 232 is provided on the base plate 12 of the heat sink.

[0039] In this embodiment, the screw 620 and the base plate 12 are in thermal contact via the spring 232. Therefore, heat from the main terminal 16 can be efficiently transferred to the water cooling jacket 310. Furthermore, variations in the thickness or warping of the components can be absorbed by the spring 232. This ensures a secure connection between the tip of the screw 620 and the water cooling jacket 310 via the spring 232. Additionally, the insulating portion 620b of the screw 620 provides insulation between the main terminal 16, through which a large current flows, and the base plate 12 and the water cooling jacket 310. Thus, insulation can be provided between the main terminal 16 and the busbar 18 and the heat sink while enabling fastening of the components and efficient heat dissipation. Furthermore, the fastening force can be improved by tightening the main terminal 16 and the busbar 18 between the nut portion 211 and the screw head of the screw 620.

[0040] Embodiment 7. Figure 10 is a cross-sectional view of a semiconductor device 700 according to Embodiment 7. In this embodiment, the screw 720 is provided so as to penetrate the busbar 18, the main terminal 16, the case 14, and the base plate 12. The screw 720 has a conductive portion 720a on the upper end side adjacent to the main terminal 16 and an insulating portion 720b on the lower end side. A metal spring 232 connects the insulating portion 720b of the screw 620 to a conductive heat sink. The spring 232 is provided on the water-cooling jacket 310 of the heat sink. The other configurations are the same as those of Embodiment 6.

[0041] In this embodiment as well, it is possible to insulate the main terminal 16 and busbar 18 from the heat sink while enabling fastening of the components and efficient heat dissipation.

[0042] The technical features described in each embodiment may be used in combination as appropriate.

[0043] 10 Water cooling jacket, 11 Nut part, 12 Base plate, 13 Pin fin, 14 Case, 15 Protrusion, 16 Main terminal, 18 Bus bar, 19 Signal terminal, 20 Screw, 24 Semiconductor chip, 26 Semiconductor chip, 28 Inner electrode, 40 Coolant liquid, 100 Semiconductor device, 200 Semiconductor device, 211 Nut part, 230 Screw, 231 Collar, 232 Spring, 300 Semiconductor device, 310 Water cooling jacket, 311 Nut part. 400 Semiconductor device, 411 Female threaded portion, 420 Screw, 420a Conductive portion, 420b Insulating portion, 500 Semiconductor device, 511 Female threaded portion, 520 Screw, 520a Conductive portion, 520b Insulating portion, 600 Semiconductor device, 620 Screw, 620a Conductive portion, 620b Insulating portion, 700 Semiconductor device, 720 Screw, 720a Conductive portion, 720b Insulating portion, 800 Semiconductor device, 811 Nut portion

Claims

1. A semiconductor device comprising: a heat sink; a case provided on the heat sink for housing a semiconductor chip; a main terminal electrically connected to the semiconductor chip and provided on the case; a nut portion embedded in the heat sink; and a conductive screw provided so as to penetrate the main terminal and the case and engage with the nut portion, wherein at least one of the heat sink or the nut portion is insulating.

2. The semiconductor device according to claim 1, characterized in that the heat sink is an insulating material.

3. The semiconductor device according to claim 2, characterized in that the nut portion is conductive.

4. The semiconductor device according to any one of claims 1 to 3, comprising a conductive base plate provided between the case and the heat sink, wherein the base plate and the screw are separated by a part of the case.

5. The semiconductor device according to claim 1, characterized in that the nut portion is insulating and the heat sink is conductive.

6. The semiconductor device according to any one of claims 1 to 5, characterized in that the main terminal and the busbar are fastened together by the screw and the nut.

7. The semiconductor device according to any one of claims 1 to 6, characterized in that the heat sink has a water-cooling jacket.

8. A semiconductor device comprising: an insulating heat sink; a case provided on the heat sink for housing a semiconductor chip; a main terminal electrically connected to the semiconductor chip and provided on the case; a conductive screw passing through the main terminal and inserted into the case; and a spring connecting the screw to the heat sink.

9. The semiconductor device according to claim 8, characterized in that the main terminal and the busbar are fastened together by the screw.

10. The semiconductor device according to claim 8 or 9, comprising a conductive base plate provided between the case and the heat sink, wherein the base plate and the screw are separated by a part of the case.

11. The semiconductor device according to any one of claims 8 to 10, characterized in that the heat sink is a water-cooled jacket.

12. A semiconductor device comprising: a conductive heat sink; a case provided on the heat sink for housing a semiconductor chip; a main terminal electrically connected to the semiconductor chip and provided on the case; and a screw that penetrates the main terminal and is inserted into the case, wherein the screw has a conductive portion on its upper end adjacent to the main terminal and an insulating portion on its lower end, and the main terminal and the heat sink are insulated by the insulating portion.

13. The semiconductor device according to claim 12, comprising a conductive water-cooling jacket and a conductive base plate provided between the water-cooling jacket and the case as the heat sink, wherein the base plate has a female threaded portion that engages with the screw, and the insulating portion is formed on the portion of the screw that engages with the female threaded portion.

14. The semiconductor device according to claim 12, comprising a conductive water-cooling jacket and a conductive base plate provided between the water-cooling jacket and the case as the heat sink, wherein the screw is provided so as to penetrate the base plate, the water-cooling jacket has a female threaded portion that engages with the screw, and the insulating portion is formed on the screw from the portion adjacent to the base plate to the portion that engages with the female threaded portion.

15. The semiconductor device according to claim 12, further comprising a spring connecting the insulating portion of the screw to the heat sink.

16. The semiconductor device according to claim 15, comprising a conductive water-cooling jacket and a conductive base plate provided between the water-cooling jacket and the case as the heat sink, wherein the spring is provided on the base plate.

17. The semiconductor device according to claim 15, comprising a conductive water-cooling jacket and a conductive base plate provided between the water-cooling jacket and the case as the heat sink, wherein the spring is provided on the water-cooling jacket.

18. The semiconductor device according to any one of claims 12 to 17, characterized in that the main terminal and the busbar are fastened together by the screw.

19. The semiconductor device according to any one of claims 1 to 18, characterized in that the semiconductor chip is formed of a wide-bandgap semiconductor.

20. The semiconductor device according to claim 19, characterized in that the wide bandgap semiconductor is silicon carbide, gallium nitride-based material, or diamond.

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