Semiconductor devices and power converters

Abstract

To provide a semiconductor device with improved heat dissipation and productivity. [Solution] The semiconductor device 101 includes a fin base 11, a heat sink base 31, and a heat transport device. The fin base 11 has an upper surface for holding a semiconductor element 15 and a lower surface 11A exposed from a sealing resin body 17 that seals the semiconductor element 15. The heat sink base 31 has a mounting surface 31A opposite to the lower surface 11A of the fin base 11. The heat transport device is provided between the fin base 11 and the heat sink base 31 and extends in a specific direction within the plane of the heat sink base 31. The fin base 11 includes a first groove 11B provided on the lower surface 11A. The heat sink base 31 includes a second groove 31B provided on the mounting surface 31A. The heat transport device is fixed by the first groove 11B and the second groove 31B.

Description

Technical Field

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

Background Art

[0002] With the miniaturization of power modules, the development of module structures using heat dissipation devices with high cooling performance has been progressing (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since a heat pipe has the characteristic of instantaneously transferring heat, it is effective in improving the heat dissipation of the module. However, there is a problem that the structure of a semiconductor device provided with a heat transport device such as a heat pipe is complex and causes a decrease in productivity. Therefore, a module structure that achieves both heat dissipation and productivity is required.

[0005] An object of the present disclosure is to provide a semiconductor device with improved heat dissipation and productivity in order to solve the above problems.

Means for Solving the Problems

[0006] The semiconductor device relating to this disclosure includes a fin base, a heat sink base, and a heat transport device. The fin base has an upper surface for holding a semiconductor element and a lower surface exposed from the sealing resin body that encapsulates the semiconductor element. The heat sink base has a mounting surface opposite to the lower surface of the fin base. Heat generated by the semiconductor element is transferred to the heat sink base via the fin base. The heat transport device is provided between the fin base and the heat sink base and extends in a specific direction within the plane of the heat sink base. The fin base includes a first groove provided on its lower surface. The heat sink base includes a second groove provided on its mounting surface. The heat transport device is fixed by the first groove and the second groove. [Effects of the Invention]

[0007] According to this disclosure, a semiconductor device is provided that offers improved heat dissipation and productivity.

[0008] The purpose, features, aspects, and advantages of this disclosure will become clearer from the following detailed description and accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view showing the configuration of the semiconductor device in Embodiment 1. [Figure 2] This is a cross-sectional view showing the configuration of the semiconductor device in Embodiment 1. [Figure 3] This is a schematic diagram showing the manufacturing method of a semiconductor device in Embodiment 1. [Figure 4] This is a conceptual diagram showing the process of integrating the fin base and the heat sink base in Embodiment 1. [Figure 5] This figure shows the configuration of a semiconductor device in a modified example of Embodiment 1. [Figure 6] This figure shows the configuration of a semiconductor device in a modified example of Embodiment 1. [Figure 7] This figure shows the configuration of a semiconductor device in a modified example of Embodiment 1. [Figure 8]This is a diagram showing the configuration of the semiconductor device in the modification of Embodiment 1. [Figure 9] This is a diagram showing the configuration of the semiconductor device in the modification of Embodiment 1. [Figure 10] This is a diagram showing the configuration of the semiconductor device in the modification of Embodiment 1. [Figure 11] This is a diagram showing the configuration of the semiconductor device in the modification of Embodiment 1. [Figure 12] This is a diagram showing the configuration of the semiconductor device in the modification of Embodiment 1. [Figure 13] This is a diagram showing the configuration of the semiconductor device in the modification of Embodiment 1. [Figure 14] This is a diagram showing the configuration of the semiconductor device in the modification of Embodiment 1. [Figure 15] This is a diagram showing the configuration of the semiconductor device in the modification of Embodiment 1. [Figure 16] This is a cross-sectional view showing the configuration of the semiconductor device in Embodiment 2. [Figure 17] This is a plan view showing the configuration of the semiconductor device in Embodiment 3. [Figure 18] This is a cross-sectional view showing the configuration of the semiconductor device in Embodiment 3. [Figure 19] This is a cross-sectional view showing the configuration of the semiconductor device in the modification of Embodiment 3. [Figure 20] This is a functional block diagram showing the configuration of the power conversion system in Embodiment 4.

Embodiments for Carrying Out the Invention

[0010] Embodiment 1. FIG. 1 is a plan view showing the configuration of the semiconductor device 101 in Embodiment 1. FIG. 2 is a cross-sectional view showing the configuration of the semiconductor device 101, and shows the cross-sectional configuration along A - A' described in FIG. 1.

[0011] The semiconductor device 101 consists of a semiconductor module 10, a heat pipe 20, and a heat sink 30. The semiconductor module 10 includes a fin base 11, an insulating material 12, a metal conductor 13A, a main terminal 13B, a control terminal 13C, a bonding material 14, a semiconductor element 15, a metal wire 16, and a sealing resin body 17. The heat sink 30 includes a heat sink base 31 and heat dissipation fins 32.

[0012] The fin base 11 has an upper surface sealed by a sealing resin body 17 and a lower surface 11A exposed from the sealing resin body 17. The fin base 11 has the function of transferring heat generated by the semiconductor element 15 to the heat sink base 31 via a metal conductor 13A or the like. The fin base 11 is formed of, for example, copper, aluminum, or an aluminum alloy. However, the material of the fin base 11 is not limited to these materials. The fin base 11 is manufactured, for example, by cutting, forging, casting, or extrusion.

[0013] The insulating material 12 is provided on the upper surface of the fin base 11. The metal conductor 13A is held on the upper surface of the fin base 11 via the insulating material 12. The main terminal 13B and the control terminal 13C are leads configured to be connectable to circuits provided outside the semiconductor device 101. The ends of the main terminal 13B and the control terminal 13C protrude from the sealing resin body 17. The main terminal 13B and the control terminal 13C may have a frame shape, for example, a metal plate processed into a predetermined shape. The metal conductor 13A may be an integral part with the main terminal 13B or the control terminal 13C.

[0014] The semiconductor element 15 is held on the surface of the metal conductor 13A via a bonding material 14. The semiconductor element 15 is held on the upper surface of the fin base 11 via its metal conductor 13A, etc. The bonding material 14 is a conductive material such as solder. The semiconductor element 15 is electrically connected to the metal conductor 13A via its bonding material 14. The semiconductor element 15 is electrically connected to the main terminal 13B and the control terminal 13C via a metal wire 16.

[0015] The semiconductor element 15 is formed from a semiconductor such as Si. The semiconductor element 15 may also be formed from a wide-bandgap semiconductor such as SiC or GaN, among compound semiconductors. The semiconductor element 15 is a power semiconductor element, a control IC (Integrated Circuit) for controlling the power semiconductor element, etc. The semiconductor element 15 is, for example, an IGBT (Insulated Gate Bipolar Transistor), a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), or a Schottky barrier diode. Alternatively, the semiconductor element 15 may be an RC-IGBT (Reverse-Conducting IGBT) in which the IGBT and freewheeling diode are formed on a single semiconductor substrate.

[0016] The sealing resin body 17 integrates the components by sealing the upper surface of the fin base 11, the insulating material 12, the metal conductor 13A, part of the main terminal 13B, part of the control terminal 13C, the bonding material 14, the semiconductor element 15, and the metal wire 16. The sealing resin body 17 is formed of, for example, epoxy resin.

[0017] The heat sink 30 in Embodiment 1 is a "crimped heat sink." The heat dissipation fins 32 are integrated with the heat sink base 31 by "crimping." The heat sink 30 may be manufactured by extrusion or casting (die casting).

[0018] The heat sink base 31 has a mounting surface 31A that is opposite to the lower surface 11A of the fin base 11. This mounting surface 31A corresponds to the upper surface of the heat sink base 31. Heat generated by the semiconductor element 15 is transferred to the heat sink base 31 via the fin base 11. The heat sink base 31 is manufactured by, for example, machining, die casting, forging, or extrusion. The heat sink base 31 is made of, for example, aluminum or an aluminum alloy.

[0019] The heat dissipation fins 32 are mounted vertically on the underside of the heat sink base 31, opposite to the mounting surface 31A. The heat dissipation fins 32 release heat transferred from the heat sink base 31 to the outside. The heat dissipation fins 32 are formed from rolled material such as aluminum or aluminum alloy. This ensures both processability and heat dissipation.

[0020] The materials of the heat sink base 31 and the heat dissipation fins 32 are not limited to those described above, and different materials may be combined. For example, from the viewpoint of heat dissipation capacity, it is preferable that the heat dissipation fins 32 be formed from a plate material mainly composed of copper, which has a higher thermal conductivity than a plate material mainly composed of aluminum. This improves the heat dissipation capacity.

[0021] The fin base 11 includes a first groove 11B provided on the lower surface 11A of the fin base 11. The heat sink base 31 includes a second groove 31B provided on the mounting surface 31A. In Embodiment 1, two first grooves 11B and two second grooves 31B are provided. These first grooves 11B and second grooves 31B extend in the same direction as the short side of the sealing resin body 17 in a plan view and are provided in positions opposite to each other.

[0022] The cross-sectional shape of the first groove 11B is tapered. In this tapered shape, the groove width at the bottom surface of the first groove 11B is narrower than the groove width at the opening surface of the first groove 11B. Similarly, the cross-sectional shape of the second groove 31B is tapered. In this tapered shape, the groove width at the bottom surface of the second groove 31B is narrower than the groove width at the opening surface of the second groove 31B.

[0023] The heat pipe 20 is an example of a heat transport device. The heat pipe 20 is provided between the fin base 11 and the heat sink base 31 and extends in a specific direction within the plane of the heat sink base 31. In Embodiment 1, two heat pipes 20 are provided and extend in the same direction as the short side of the sealing resin body 17. The heat pipe 20 has the same length as the short side of the sealing resin body 17. The heat pipe 20 is fitted and embedded in the first groove 11B and the second groove 31B and is in direct contact with the first groove 11B and the second groove 31B. In other words, the heat pipe 20 is fixed by the first groove 11B and the second groove 31B. Preferably, the heat pipe 20 is made of a material with better thermal conductivity than, for example, the fin base 11 and the heat sink base 31. The heat pipe 20 is made of, for example, copper.

[0024] Furthermore, the fin base 11 includes a first uneven shape provided on its lower surface 11A, separate from the first groove 11B. The first uneven shape in Embodiment 1 includes a plurality of recesses 11C. The side walls of the recesses 11C are inclined. Similarly, the heat sink base 31 includes a second uneven shape provided on its mounting surface 31A, separate from the second groove 31B. The second uneven shape in Embodiment 2 includes a plurality of protrusions 31C. The side walls of the protrusions 31C are inclined. The first uneven shape fits into the second uneven shape, and the recesses 11C are in direct contact with the protrusions 31C.

[0025] Furthermore, of the multiple recesses 11C, the depths of the two outer recesses 11D closest to both ends of the fin base 11 are greater than the depths of the other recesses 11C. Of the multiple protrusions 31C, the heights of the two outer protrusions 31D closest to both ends of the heat sink base 31 are greater than the heights of the other protrusions 31C. These two outer protrusions 31D fit into and directly contact the two outer recesses 11D, respectively.

[0026] Figure 3 is a schematic diagram showing the manufacturing method of the semiconductor device 101 in Embodiment 1. Here, as an example, a crimped heat sink 30 manufactured by crimping is used. However, the following manufacturing method can be applied even if the heat sink 30 is of a different type.

[0027] First, as shown in Figure 3(a), the heat sink 30 is set in the crimping tool 33. Next, the heat pipe 20 is set in the second groove 31B of the heat sink base 31 of the heat sink 30. Then, the semiconductor module 10 is set on the mounting surface 31A of the heat sink base 31. After that, as shown in Figure 3(b), the semiconductor module 10 is pressed and a load 19 is applied from above to below. This load 19 causes the semiconductor module 10, the heat pipe 20, and the heat sink 30 to become one with each other.

[0028] Figure 4 is a conceptual diagram showing the integration process of the fin base 11 and the heat sink base 31. Based on the material properties of the fin base 11 and the heat sink base 31, a recess 11C is provided on one of the fin base 11 and a protrusion 31C is provided on the other. In Embodiment 1, the fin base 11 is more easily plastically deformed than the heat sink base 31. The recess 11C is provided on the fin base 11, which is more easily plastically deformed, and the protrusion 31C is provided on the heat sink base 31, which is less easily plastically deformed.

[0029] When a load 19 is applied to the semiconductor module 10, the recess 11C of the fin base 11 is plastically deformed by the protrusion 31C of the heat sink base 31, and the processing progresses. Since both the side walls of the recess 11C and the side walls of the protrusion 31C have inclined surfaces, the stress applied to the fin base 11 is decomposed into horizontal and vertical stresses. The horizontal stress 35 is transmitted to the first groove 11B of the fin base 11. Then, surface pressure is applied from the side wall of the first groove 11B to the heat pipe 20, causing the first groove 11B to plastically deform inward. As a result, the fin base 11 and the heat pipe 20 become integrated while in contact with each other.

[0030] Furthermore, the semiconductor module 10 and the heat sink 30 are integrated while surface pressure is applied to the recess 11C and the protrusion 31C. As a result, the recess 11C and the protrusion 31C are integrated in a state of contact with each other.

[0031] As described above, in the manufacturing method of the semiconductor device 101 of Embodiment 1, when the semiconductor module 10 and the heat sink 30 are integrated, the heat pipe 20 is also integrated at the same time.

[0032] Based on the material properties of the fin base 11 and the heat sink base 31, a structure in which the relationship between the recess 11C and the protrusion 31C is reversed may be applied. For example, if the heat sink base 31 is more easily plastically deformed than the fin base 11, a structure in which the recess is formed in the heat sink base 31 and the protrusion is formed in the fin base 11 may be applied. Even with such a structure, the above effect will occur.

[0033] When the fin base 11 and heat sink base 31 are made of aluminum and the heat pipe 20 is made of copper, the fin base 11 and heat sink base 31 are more easily deformed than the heat pipe 20. Therefore, they are easier to process and productivity is improved.

[0034] In such a semiconductor device 101, the heat generated by the semiconductor element 15 is instantaneously conducted and diffused in a specific direction within the plane of the heat sink base 31 via the heat pipe 20. As a result, the heat dissipation efficiency of the heat sink 30 is improved, and the temperature reached by the semiconductor element 15 is stably reduced.

[0035] The fin base 11, heat pipe 20, and heat sink base 31 are in direct contact with each other. Since the process of applying thermal conductive grease to each connection point is unnecessary in the manufacturing process of the semiconductor device 101, the productivity of the semiconductor device 101 is improved.

[0036] Since thermal conductive grease is not used at each connection point, low thermal resistance is achieved. In addition, pump-out and bleed, which can occur when thermal conductive grease is used, do not occur, resulting in a semiconductor device 101 with excellent long-term reliability.

[0037] The fin base 11 and heat sink base 31 are manufactured by mold processing such as forging, extrusion, or die casting. Since such metal processing offers excellent productivity in mass production, the first groove 11B and the second groove 31B for arranging the heat pipes 20 can be formed without reducing the productivity of the semiconductor device 101.

[0038] When a crimped heat sink is used in which the heat sink base 31 and the heat dissipation fins 32 are integrated by crimping, there are no processing constraints such as aspect ratio constraints that occur with casting (die-casting) or extrusion. Therefore, a high degree of design freedom is obtained for the heat dissipation fins 32, and it is possible to design the heat dissipation fins 32 in a way that maximizes the heat dissipation capacity of the heat sink 30.

[0039] The inclined surfaces of the recessed portion 11C and the convex portion 31C ensure that the heat pipe 20 makes secure contact with the fin base 11 during the integration process of the fin base 11 and the heat sink base 31. As a result, contact thermal resistance is reduced, and the heat generated by the semiconductor element 15 is easily transferred to and diffused by the heat pipe 20. Furthermore, the inclined shape ensures that the fin base 11 makes secure contact with the heat sink base 31. As a result, contact thermal resistance is reduced, and the heat generated by the semiconductor element 15 is easily conducted from the fin base 11 to the heat sink base 31 and released into the air from the heat dissipation fins 32.

[0040] The first groove 11B of the fin base 11 for positioning the heat pipe 20 functions as a deformation buffer during the integration process of the fin base 11 and the heat sink base 31. For example, if the positions of the center of the recess 11C and the center of the convex portion 31C are misaligned, the press load 19 required to plastically deform the fin base 11 will increase. However, the deformation buffer minimizes the increase in the press load 19.

[0041] Since the first groove 11B of the fin base 11 functions as a deformation buffer, it is possible to set larger dimensional tolerances for the recess 11C and the protrusion 31C. As a result, the productivity of the fin base 11 and the heat sink base 31 is improved.

[0042] A similar effect simplifies the positioning of the recessed portion 11C of the fin base 11 relative to the protrusion 31C of the heat sink base 31 during the integration process of the fin base 11 and the heat sink base 31. As a result, the productivity of the semiconductor device 101 is improved.

[0043] The inclined shapes of the recessed portion 11C and the convex portion 31C function as a demolding angle when the fin base 11 and heat sink base 31 are manufactured in a mold, thereby improving the lifespan of the mold.

[0044] Of the multiple protrusions 31C on the heat sink base 31, the height of the two outer protrusions 31D closest to both ends of the heat sink base 31 is greater than the height of the other protrusions 31C, thereby reducing the tilt of the semiconductor module 10 due to uneven pressure during pressing. This prevents excessive force from being applied to the heat pipe 20, minimizing damage to the heat pipe 20 due to pressing. The performance of the heat pipe 20 is stabilized, and the productivity of the semiconductor device 101 is also improved.

[0045] In summary, the semiconductor device 101 in Embodiment 1 includes a fin base 11, a heat sink base 31, and a heat transport device. The fin base 11 has an upper surface for holding a semiconductor element 15 and a lower surface 11A exposed from the sealing resin body 17 that seals the semiconductor element 15. The heat sink base 31 has a mounting surface 31A opposite to the lower surface 11A of the fin base 11. Heat generated by the semiconductor element 15 is transferred to the heat sink base 31 via the fin base 11. The heat transport device is provided between the fin base 11 and the heat sink base 31 and extends in a specific direction within the plane of the heat sink base 31. The fin base 11 includes a first groove 11B provided on the lower surface 11A. The heat sink base 31 includes a second groove 31B provided on the mounting surface 31A. The heat transport device is fixed by the first groove 11B and the second groove 31B.

[0046] This configuration improves the heat dissipation and productivity of the semiconductor device 101.

[0047] Figures 5 to 15 show the configuration of a semiconductor device in a modified example of Embodiment 1.

[0048] The heat pipe 20 of the semiconductor device 101A shown in Figure 5 is shorter than the length of the short side of the sealing resin body 17. Even with this configuration, the effects described in Embodiment 1 can be obtained.

[0049] The heat pipe 20 of the semiconductor device 101B shown in Figure 6 is longer than the length of the shorter side of the sealing resin body 17. Figure 7 shows a cross-sectional configuration along B-B' as described in Figure 6. Such a heat pipe 20 diffuses the heat generated by the semiconductor element 15 throughout the heat sink base 31. As a result, the temperature reached by the semiconductor element 15 is reduced.

[0050] Furthermore, although not shown in the figures, the heat pipe 20 may extend in the same direction as the long side of the sealing resin body 17. The heat pipe 20 may have the same length as the long side of the sealing resin body 17, or it may have a different length. In either case, the effects described in Embodiment 1 can be obtained.

[0051] In the semiconductor device 101C shown in Figure 8, a TIM (Thermal Interface Material) 21 is inserted between the heat pipe 20 and the second groove 31B of the heat sink base 31. The TIM 21 is, for example, thermal conductive grease. This configuration reduces the contact thermal resistance between the heat pipe 20 and the heat sink base 31.

[0052] In the semiconductor device 101D shown in Figure 9, the second groove 31B of the heat sink base 31 has a curved shape rather than a tapered shape. Furthermore, in the semiconductor device 101E shown in Figure 10, not only the second groove 31B but also the first groove 11B of the fin base 11 has a curved shape. Even with this configuration, the effects described in Embodiment 1 can be obtained.

[0053] In the semiconductor device 101F shown in Figure 11, if W1 is the groove width at the opening surface of the first groove 11B, H1 is the depth of the first groove 11B, W2 is the groove width at the opening surface of the second groove 31B, H2 is the depth of the second groove 31B, and r is the radius of the heat pipe 20, then the dimensional relationships W1≧2r, W2≧2r, and H1+H2≧2r are satisfied. This configuration prevents excessive stress from being applied to the heat pipe 20 during the process of integrating the fin base 11 and the heat sink base 31. As a result, malfunctions of the heat pipe 20 after integration are reduced.

[0054] The heatsink 30A of the semiconductor device 101G shown in Figure 12 does not have heat dissipation fins 32. The heatsink 30B of the semiconductor device 101H shown in Figure 13 is manufactured by extrusion. The heatsink 30C of the semiconductor device 101J shown in Figure 14 is manufactured by casting (die casting). The heatsink 30D of the semiconductor device 101K shown in Figure 15 is a water-cooled heatsink and is equipped with pin fins as heat dissipation fins 32. In any of these configurations, the effects described in Embodiment 1 can be obtained.

[0055] Embodiment 2. Figure 16 is a cross-sectional view showing the configuration of the semiconductor device 102 in Embodiment 2. The semiconductor device 102 includes a bonding material 22 provided between the lower surface 11A of the fin base 11 and the mounting surface 31A of the heat sink base 31. The bonding material 22 in Embodiment 2 is provided so as to avoid the first groove 11B and the second groove 31B. The bonding material 22 contacts the lower surface 11A of the fin base 11 and the mounting surface 31A of the heat sink base 31, thereby bonding the fin base 11 and the heat sink base 31. The bonding material 22 is, for example, solder.

[0056] In Embodiment 2, the fin base 11 and the heat sink base 31 are integrated by a bonding material 22. Even with this configuration, the same effects as in Embodiment 1 can be obtained.

[0057] Embodiment 3. Figure 17 is a plan view showing the configuration of the semiconductor device 103 in Embodiment 3. Figure 18 is a cross-sectional view showing the configuration of the semiconductor device 103, and shows the cross-sectional configuration along C-C' shown in Figure 17.

[0058] The semiconductor device 103 includes a plurality of semiconductor modules 10, a heat sink 30, heat pipes 20, a cooling fan 40, a mounting plate 50, and a housing 60. In Embodiment 3, two heat sinks 30 and six semiconductor modules 10 are provided, with three semiconductor modules 10A, 10B, and 10C mounted on each heat sink 30. The six semiconductor modules 10 have the same configuration as in Embodiment 1. In addition, four heat pipes 20 are provided as heat transport devices, with two heat pipes 20 mounted on each heat sink 30.

[0059] The cooling fan 40 is attached to the housing 60 and blows air in one direction. The three semiconductor modules 10A, 10B, and 10C mounted on each heatsink 30 are arranged in a line on the heatsink 30 along the airflow direction 41 supplied by the cooling fan 40. The airflow direction 41 is parallel to the wind velocity vector and corresponds to the direction of the arrow shown in Figure 17. The heat pipes 20 are provided between the semiconductor modules 10 and the heatsinks 30 and extend along the direction in which the semiconductor modules 10 are positioned. Each heat pipe 20 is routed to connect the three semiconductor modules 10A, 10B, and 10C arranged along the airflow direction 41. The mounting plate 50 has an opening into which the heat dissipation fins 32 of the heatsink 30 are inserted. The heatsink base 31 of the heatsink 30 is held at the edge of the opening. The mounting plate 50 and the heatsink base 31 are fixed to the housing 60 by screws 51. In other words, the heatsink 30, which integrates the semiconductor module 10 and the heat pipe 20, is held on the mounting plate 50. The housing 60 holds the heatsink 30 and the semiconductor module 10 via the mounting plate 50.

[0060] The heat generated by the semiconductor element 15 is transferred to the heat sink 30 below the semiconductor module 10 and dissipated by the air blown by the cooling fan 40. If the heat pipe 20 is not provided, the temperatures reached by the three semiconductor modules 10A, 10B, and 10C will have the relationship: temperature of semiconductor module 10C < temperature of semiconductor module 10B < temperature of semiconductor module 10A. This is because the heat dissipation fins 32 of semiconductor module 10A, which is located downwind, receive air heated by the heat released from semiconductor modules 10B and 10C, which are located upwind, reducing the cooling efficiency. As a result, the temperature reached by semiconductor module 10A, which is located downwind, tends to be higher. Therefore, the temperature reached by each semiconductor module 10 within the semiconductor device 103 varies. In other words, the electrical characteristics of each semiconductor module 10 vary, and the probability of failure of a particular semiconductor module 10 tends to be higher.

[0061] In Embodiment 3, a heat pipe 20 is provided between the fin base 11 and the heat sink base 31 in a state where the contact thermal resistance is low. The heat pipe 20 is also routed to connect the three semiconductor modules 10A, 10B, and 10C. The heat generated by the semiconductor element 15 is instantly conducted from the high-temperature part to the low-temperature part via the heat pipe 20, and the temperature reached on the fin base 11 on which the three semiconductor modules 10A, 10B, and 10C are mounted is averaged. As the variation in the temperature reached by the semiconductor modules 10 is reduced, the variation in the electrical characteristics of the semiconductor modules 10 is reduced, and the probability of failure is also reduced. In addition, the temperature reached by each semiconductor module 10 within the semiconductor device 103 is also reduced, so the semiconductor device 103 can be miniaturized.

[0062] Figure 19 is a cross-sectional view showing the configuration of a semiconductor device 103A in a modified example of Embodiment 3. A support member 61 is provided between two heat sinks 30. The support member 61 is provided between a mounting plate 50 connecting the two heat sinks 30 and the bottom of the housing 60. The support member 61 also extends along the airflow direction 41 from the cooling fan 40.

[0063] The support member 61 corrects the displacement of the mounting plate 50. That is, the support member 61 prevents the mounting plate 50 connecting the two heat sinks 30 from bending and prevents the screws 51 from loosening. The support member 61 may also be elastic. The above effect is more pronounced when the support member 61 is elastic.

[0064] The support member 61 functions as a side wall of the air passage, increasing the airflow velocity between the heat dissipation fins 32. As a result, the temperature reached by the semiconductor module 10 is reduced.

[0065] The number of heatsinks 30 is not limited to two. The number of semiconductor modules 10 is not limited to six. The above effects can be obtained even if the number of heatsinks 30 and semiconductor modules 10 is other than the specified number.

[0066] Embodiment 4. Figure 20 is a functional block diagram showing the configuration of the power conversion system in Embodiment 4. The power conversion system includes a power supply 400, a power converter 200, and a load 300. In this power conversion system, one of the semiconductor devices from Embodiments 1 to 3 is applied to the power converter 200. Here, an example is shown where the power converter 200 is a three-phase inverter, but the configuration of the power converter 200 is not limited to this.

[0067] The power supply 400 is a DC power supply that supplies DC power to the power converter 200. The power supply 400 can have various configurations, such as a DC grid, a solar cell, or a battery. The power supply 400 may also be a rectifier circuit or AC / DC converter connected to an AC grid. The power supply 400 may also be a DC / DC converter that converts DC power output from a DC grid into a predetermined power.

[0068] The power converter 200 is connected to the power supply 400 and the load 300. The power converter 200 in Embodiment 4 is a three-phase inverter that converts DC power supplied from the power supply 400 into AC power. The power converter 200 supplies this AC power to the load 300.

[0069] The load 300 is driven by AC power supplied from the power converter 200. The load 300 in Embodiment 4 is a three-phase motor. This three-phase motor is not limited to a specific application and can be mounted in various electrical equipment. Three-phase motors are used in hybrid vehicles, electric vehicles, railway vehicles, elevators, air conditioning equipment, and the like.

[0070] The details of the power converter 200 are described below. The power converter 200 includes a main conversion circuit 201 and a control circuit 203.

[0071] The main conversion circuit 201 includes at least one semiconductor device 202 and a drive circuit (not shown). The semiconductor device 202 corresponds to the semiconductor device shown in any of the embodiments 1 to 3 described above.

[0072] The semiconductor device 202 constitutes a two-level three-phase full-bridge circuit (not shown). The three-phase full-bridge circuit includes six switching elements (not shown) and six freewheeling diodes (not shown). At least one of these switching elements and freewheeling diodes corresponds to the semiconductor element 15 included in the semiconductor device shown in any of embodiments 1 to 3.

[0073] The three-phase full-bridge circuit includes three upper arms and three lower arms. Each upper and lower arm includes one switching element and one freewheeling diode connected in antiparallel to that switching element. In addition, the switching element in one upper arm is connected in series with the switching element in one lower arm, and these constitute a pair of upper and lower arms. In other words, the three-phase full-bridge circuit includes three pairs of upper and lower arms. The three pairs of upper and lower arms correspond to the U phase, V phase, and W phase of the three-phase full-bridge circuit, respectively. The output terminals of the three pairs of upper and lower arms, i.e., the three output terminals of the main converter circuit 201, are connected to the load 300.

[0074] The main conversion circuit 201 converts the DC power supplied from the power supply 400 into AC power through the switching operation of a switching element. The main conversion circuit 201 supplies this AC power to the load 300 via its output terminal.

[0075] The drive circuit may be built into the semiconductor device 202 or may be provided separately from the semiconductor device 202. The drive circuit generates a drive signal to drive the switching elements of the main conversion circuit 201 according to the control signal output from the control circuit 203. The drive circuit supplies this drive signal to the control electrodes of the switching elements of the semiconductor device 202.

[0076] A drive signal is a signal that turns on a switching element or a signal that turns off a switching element. More specifically, when a switching element is kept in the ON state, the drive signal is a voltage signal (ON signal) that is equal to or greater than the threshold voltage of the switching element. When a switching element is kept in the OFF state, the drive signal is a voltage signal (OFF signal) that is less than the threshold voltage of the switching element.

[0077] The control circuit 203 outputs a control signal to the drive circuit to control the drive circuit. In doing so, the control circuit 203 calculates the time (on time) that each switching element of the main conversion circuit 201 should be in the ON state based on the power to be supplied to the load 300, and generates a control signal. In other words, the control circuit 203 generates a control signal so that the main conversion circuit 201 is controlled by PWM (Pulse Width Modulation). The control circuit 203 outputs a control signal to the drive circuit so that the drive circuit outputs an ON signal to the switching element that should be in the ON state and an OFF signal to the switching element that should be in the OFF state. In this way, the control circuit 203 controls the switching elements of the main conversion circuit 201 so that a predetermined power is supplied to the load 300.

[0078] In such a power converter 200, the semiconductor device shown in any of Embodiments 1 to 3 is applied to the main conversion circuit 201. Therefore, the reliability of the power converter 200 is improved.

[0079] In Embodiment 4, an example was shown in which the power converter 200 is a two-level three-phase inverter, but the configuration of the power converter 200 is not limited to this. For example, the power converter 200 may be a multi-level power converter, such as a three-level converter. Alternatively, the power converter 200 may be a single-phase inverter for supplying power to a single-phase load. If the load 300 is a DC load, the power converter 200 may be a DC / DC converter or an AC / DC converter. If the load 300 is a solar power generation system, an energy storage system, etc., the power converter 200 may be a power conditioner.

[0080] In Embodiment 4, an example was shown where the load 300 is a three-phase motor, but the configuration of the load 300 is not limited to that. For example, the load 300 may be an electrical discharge machine, a laser processing machine, an induction cooker, or a non-contact power supply system.

[0081] This disclosure allows for the free combination of each embodiment, and enables the modification or omission of each embodiment as appropriate.

[0082] The various aspects of this disclosure are summarized below as an appendix.

[0083] (Note 1) A fin base having an upper surface for holding a semiconductor element and a lower surface exposed from the sealing resin body that seals the semiconductor element, A heat sink base having a mounting surface opposite to the lower surface of the fin base, wherein heat generated by the semiconductor element is transferred via the fin base, The heat transfer device is provided between the fin base and the heat sink base and extends in a specific direction within the plane of the heat sink base, The fin base includes a first groove provided on the lower surface, The heat sink base includes a second groove provided on the mounting surface, The heat transport device is a semiconductor device fixed by the first groove and the second groove.

[0084] (Note 2) The fin base includes a first uneven shape provided on the lower surface, The heat sink base includes a second uneven shape provided on the mounting surface, The semiconductor device described in Appendix 1, wherein the first uneven shape is fitted to the second uneven shape.

[0085] (Note 3) The fin base includes a plurality of recesses as the first uneven shape, Of the plurality of recesses, the depths of the two outer recesses closest to both ends of the fin base are greater than the depths of the other recesses. The heat sink base includes a plurality of protrusions as the second uneven shape, Of the multiple protrusions, the height of the two outer protrusions closest to both ends of the heat sink base is higher than the height of the other protrusions. The semiconductor device according to Appendix 2, wherein the two outer recesses are fitted into the two outer protrusions, respectively.

[0086] (Note 4) The cross-sectional shape of the first groove has a tapered shape in which the groove width at the bottom surface of the first groove is narrower than the groove width at the opening surface of the first groove. The cross-sectional shape of the second groove is tapered, with the groove width at the bottom of the second groove being narrower than the groove width at the opening surface of the second groove. The heat transport device is a heat pipe, A semiconductor device according to any one of the appendices 1 to 3, wherein, when the groove width at the opening surface of the first groove is W1, the depth of the first groove is H1, the groove width at the opening surface of the second groove is W2, the depth of the second groove is H2, and the radius of the heat pipe is r, the dimensional relationships W1≧2r, W2≧2r, and H1+H2≧2r are satisfied.

[0087] (Note 5) A semiconductor device according to any one of the appendices 1 to 4, comprising a bonding material provided between the fin base and the heat sink base, which contacts the lower surface of the fin base and the mounting surface of the heat sink base to join the fin base and the heat sink base.

[0088] (Note 6) Multiple semiconductor modules, A heatsink on which the aforementioned multiple semiconductor modules are mounted, The system comprises a heat transport device provided between the semiconductor module and the heat sink, Each of the aforementioned plurality of semiconductor modules is The fin base includes an upper surface for holding a semiconductor element and a lower surface exposed from the sealing resin body that seals the semiconductor element, The fin base includes a first groove provided on the lower surface, The aforementioned heatsink is The heat sink base includes a mounting surface facing the lower surface of the fin base, and heat generated by the semiconductor element is transferred through the fin base. The heat sink base includes a second groove provided on the mounting surface, The heat transport device extends in a specific direction within the plane of the heat sink base and is fixed by the first groove and the second groove, wherein the heat transport device is a semiconductor device.

[0089] (Note 7) Cooling fan and The system comprises a housing that holds the heat sink and the plurality of semiconductor modules, The semiconductor device according to Appendix 6, wherein the plurality of semiconductor modules are arranged on the heat sink along the direction of airflow from the cooling fan.

[0090] (Note 8) A main conversion circuit that converts and outputs the input power, including a semiconductor device described in any one of the items from Appendix 1 to Appendix 7, A power conversion device comprising: a control circuit that outputs a control signal to the main conversion circuit to control the main conversion circuit. [Explanation of Symbols]

[0091] 10 Semiconductor module, 10A~10C Semiconductor module, 11 Fin base, 11A Bottom surface, 11B First groove, 11C Recess, 11D Outer recess, 12 Insulating material, 13A Metal conductor, 13B Main terminal, 13C Control terminal, 14 Bonding material, 15 Semiconductor element, 16 Metal wire, 17 Encapsulating resin body, 19 Load, 20 Heat pipe, 21 TIM, 22 Bonding material, 30 Heat sink, 30A~30D Heat sink, 31 Heat sink base, 31A Mounting surface, 31B Second groove, 31C Protrusion, 31D Outer protrusion, 32 Heat dissipation fin, 33 Crimping tool, 35 Stress, 40 Cooling fan, 41 Airflow direction, 50 Mounting plate, 51 Screw, 60 Housing, 61 Support member, 101~103A Semiconductor equipment, 200 power converter, 201 main converter circuit, 202 semiconductor equipment, 203 control circuit, 300 load, 400 power supply.

Claims

1. A fin base having an upper surface for holding a semiconductor element and a lower surface exposed from the sealing resin body that seals the semiconductor element, A heat sink base having a mounting surface opposite to the lower surface of the fin base, wherein heat generated by the semiconductor element is transferred via the fin base, The heat transfer device is provided between the fin base and the heat sink base and extends in a specific direction within the plane of the heat sink base, The fin base includes a first groove provided on the lower surface, The heat sink base includes a second groove provided on the mounting surface, The heat transport device is a semiconductor device fixed by the first groove and the second groove.

2. The fin base includes a first uneven shape provided on the lower surface, The heat sink base includes a second uneven shape provided on the mounting surface, The semiconductor device according to claim 1, wherein the first uneven shape is fitted into the second uneven shape.

3. The fin base includes a plurality of recesses as the first uneven shape, Of the plurality of recesses, the depths of the two outer recesses closest to both ends of the fin base are deeper than the depths of the other recesses. The heat sink base includes a plurality of protrusions as the second uneven shape, Of the multiple protrusions, the height of the two outer protrusions closest to both ends of the heat sink base is higher than the height of the other protrusions. The semiconductor device according to claim 2, wherein the two outer recesses are fitted into the two outer protrusions, respectively.

4. The cross-sectional shape of the first groove has a tapered shape in which the groove width at the bottom surface of the first groove is narrower than the groove width at the opening surface of the first groove. The cross-sectional shape of the second groove has a tapered shape in which the groove width at the bottom surface of the second groove is narrower than the groove width at the opening surface of the second groove. The heat transport device is a heat pipe, The semiconductor device according to claim 1, wherein, when the groove width at the opening surface of the first groove is W1, the depth of the first groove is H1, the groove width at the opening surface of the second groove is W2, the depth of the second groove is H2, and the radius of the heat pipe is r, the dimensional relationships W1 ≥ 2r, W2 ≥ 2r, and H1 + H2 ≥ 2r are satisfied.

5. The semiconductor device according to claim 1, further comprising a bonding material provided between the fin base and the heat sink base, which contacts the lower surface of the fin base and the mounting surface of the heat sink base to join the fin base and the heat sink base.

6. Multiple semiconductor modules, A heatsink on which the aforementioned multiple semiconductor modules are mounted, The system comprises a heat transport device provided between the semiconductor module and the heat sink, Each of the aforementioned plurality of semiconductor modules is The fin base includes an upper surface for holding a semiconductor element and a lower surface exposed from the sealing resin body that seals the semiconductor element, The fin base includes a first groove provided on the lower surface, The aforementioned heatsink is The heat sink base includes a mounting surface facing the lower surface of the fin base, and heat generated by the semiconductor element is transferred through the fin base. The heat sink base includes a second groove provided on the mounting surface, The heat transport device extends in a specific direction within the plane of the heat sink base and is fixed by the first groove and the second groove, wherein the heat transport device is a semiconductor device.

7. Cooling fan and The system comprises a housing that holds the heat sink and the plurality of semiconductor modules, The semiconductor device according to claim 6, wherein the plurality of semiconductor modules are arranged on the heat sink along the direction of airflow from the cooling fan.

8. A semiconductor device according to claim 1, comprising a main conversion circuit that converts and outputs input power, A power conversion device comprising: a control circuit that outputs a control signal to the main conversion circuit to control the main conversion circuit.

Images