Cooler, and semiconductor device

Abstract

This cooler comprises: a heat dissipation substrate (210) including a first main surface (210S1) on which one or more semiconductor elements (10) are mounted and a second main surface (210S2) which has a fin part provided thereto; a case body (200) which is in close contact with the second main surface and accommodates the fin part; and a structural body (240). The case body includes a first wall part (200M1), a second wall part (200M2) facing the first wall part, an introduction port (204A) through which a refrigerant is introduced into the case body, and a discharge port (204B) which is positioned in the direction of a main line (L) from the first wall part toward the second wall part with respect to the introduction port and through which the refrigerant is discharged from the inside of the case body. The structural body takes in the refrigerant flowing in from the introduction port, guides the refrigerant in a guide direction that intersects the main line, and causes the refrigerant to flow out from a position corresponding to the fin part.

Description

Cooler and semiconductor device

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

[0002] Conventionally, semiconductor devices including a semiconductor module and a cooler for cooling the semiconductor module have been known. Liquid-cooling coolers that use a liquid as a refrigerant are also known. Patent Documents 1 and 2 disclose cooling structures including a heat dissipation substrate bonded to a semiconductor module and a box-shaped cooling case with one open side attached to the heat dissipation substrate. In these cooling structures, the heat dissipation substrate is provided with heat dissipation fins, and the cooling case is attached to the heat dissipation substrate so as to house the fins. The cooling case also has an inlet and an outlet, and the fins are cooled by the coolant by circulating the coolant from the inlet to the outlet.

[0003] Furthermore, Patent Documents 1 and 2 also show a structure in which convex bodies are provided inside the cooling case, and the cooling liquid flowing in from the inlet is diffused by the convex bodies, thereby improving the cooling efficiency.

[0004] International Publication No. 2014 / 069174 Japanese Patent Application Laid-Open No. 2020-145245

[0005] However, in conventional cooling structures, the coolant does not diffuse sufficiently in a direction intersecting the line connecting the inlet and outlet. Therefore, the cooling effect weakens the further away from the line, resulting in a rise in the temperature of the semiconductor elements. This creates a problem of temperature differences between the semiconductor elements.

[0006] The present disclosure aims to provide a cooler and a semiconductor device that can suppress temperature differences depending on positions in one or more semiconductor elements and reduce the temperature at the position with the highest temperature.

[0007] A cooler according to one aspect of the present disclosure is a cooler comprising: a heat dissipation substrate including a first main surface on which one or more semiconductor elements are mounted and a second main surface on which a fin portion is provided; a case body that is in close contact with the second main surface and houses the fin portion; and a structure, wherein the case body includes a first wall portion, a second wall portion opposite the first wall portion, an inlet port for introducing a refrigerant into the interior of the case body, and an outlet port that is located in the direction of a main line from the first wall portion to the second wall portion relative to the inlet port and discharges the refrigerant from the interior of the case body, and the structure takes in the refrigerant that flows in from the inlet port, guides the refrigerant in a guide direction that intersects the main line, and allows it to flow out from a position corresponding to the fin portion.

[0008] A semiconductor device according to one aspect of the present disclosure is a semiconductor device including one or more semiconductor elements and a cooler that cools the semiconductor elements, wherein the cooler includes a heat dissipation substrate including a first main surface on which the semiconductor elements are mounted and a second main surface on which a fin portion is provided, a case body that is in close contact with the second main surface and accommodates the fin portion, and a structure, wherein the case body includes a first wall portion, a second wall portion opposite the first wall portion, an inlet port for introducing a refrigerant into the interior of the case body, and an outlet port that is located in the direction of a main line from the first wall portion to the second wall portion relative to the inlet port and discharges the refrigerant from the interior of the case body, and the structure takes in the refrigerant that flows in from the inlet port, guides the refrigerant in a guide direction that intersects the main line, and allows it to flow out from a position corresponding to the fin portion.

[0009] 6 is a perspective view showing an example of a configuration of a semiconductor device according to an embodiment of the present disclosure. FIG. 7 is a plan view showing an example of a configuration of a semiconductor device. FIG. 8 is a front view of the semiconductor device viewed from the inlet side. FIG. 9 is a view showing a cross section of the semiconductor device taken along the IV-IV cross section line in FIG. 2. FIG. 10 is a view of the semiconductor device viewed from the V-V cross section line in FIG. 2. FIG. 11 is a perspective view of a case body viewed from above. FIG. 12 is a plan view of the case body viewed from above. FIG. 13 is a view showing a cross section of the case body taken along the VIII-VIII cross section line in FIG. 6. FIG. 14 is a view of the case body viewed from the IX-IX cross section line in FIG. 15. FIG. 16 is a view showing a schematic diagram of a refrigerant flow as viewed from above the case body. FIG. 17 is a view showing a schematic diagram of a refrigerant flow in a cross section of the case body. FIG. 18 is a view showing simulation results of the temperatures of six semiconductor elements mounted in a cooler. FIG. 19 is a view showing simulation results of pressure loss in a cooler. FIG. 19 is a view showing an example of a configuration of a case body according to a first modified example of the present disclosure. FIG. 20 is an exploded perspective view showing an example of a configuration of a case body according to a second modified example of the present disclosure. FIG. 21 is a cross section of a semiconductor device according to a seventh modified example of the present disclosure. FIG. 22 is a cross section of a semiconductor device according to an eighth modified example of the present disclosure. FIG. 23 is a plan view of a semiconductor device according to a ninth modified example of the present disclosure. 22. A circuit diagram of a power conversion device (inverter circuit). FIG. 23 is a plan view of a semiconductor device according to another aspect of the ninth modified example. FIG. 24 is a plan view of a semiconductor device according to another aspect of the ninth modified example. FIG. 25 is a plan view of a semiconductor device according to a tenth modified example. FIG. 26 is a cross-sectional view taken along the XXIII-XXIII cross-sectional line in FIG. 22. FIG. 27 is a plan view of a semiconductor device according to an eleventh modified example. FIG. 28 is a plan view of a semiconductor device according to a twelfth modified example. FIG. 29 is a plan view of a semiconductor device according to another aspect of the twelfth modified example.

[0010] Preferred embodiments of the present disclosure will be described below with reference to the drawings. The dimensions and scale of each part in the drawings may differ from the actual dimensions and scale, and some parts may be shown schematically to facilitate understanding. Furthermore, unless otherwise specified in the following description to the effect that the present disclosure is limited, the scope of the present disclosure is not limited to the embodiments described below. The scope of the present disclosure includes equivalents of the embodiments.

[0011] 1. Embodiment Fig. 1 is a perspective view showing an example of the configuration of a semiconductor device 1 according to an embodiment of the present disclosure, and Fig. 2 is a plan view showing an example of the configuration of the semiconductor device 1. Fig. 1 is also an assembly diagram showing a state in which a semiconductor element 10 is mounted on a cooler 20. Fig. 2 is also a perspective view showing the internal structure of the cooler 20.

[0012] The semiconductor device 1 includes one or more semiconductor elements 10 and a cooler 20 on which the semiconductor elements 10 are mounted. The semiconductor elements 10 are switching devices such as an insulated gate bipolar transistor (IGBT) and a metal oxide semiconductor field effect transistor (MOSFET). At least one of the multiple semiconductor elements 10 may be a wide bandgap semiconductor element. A wide bandgap semiconductor element is a semiconductor element having a larger bandgap than a silicon semiconductor element, such as a semiconductor element containing SiC, GaN, diamond, a gallium nitride-based material, a gallium oxide-based material, AlN, AlGaN, or ZnO. A wide bandgap semiconductor element can achieve a higher switching speed than a silicon semiconductor element. The semiconductor element 10 may be bonded to a conductive pattern provided on an insulating substrate and mounted on the cooler 20 via the conductive pattern and the insulating substrate.

[0013] The semiconductor device 1 of this embodiment includes two or more semiconductor elements 10, and as shown in Fig. 2, the semiconductor elements 10 are mounted on the cooler 20 in a state where they are arranged in a row with spaces between them. The spaces between the semiconductor elements 10 may be regular or irregular.

[0014] Fig. 3 is a view of the semiconductor device 1 as viewed from the side of the inlet 204A. Fig. 4 is a view showing a cross section of the semiconductor device 1 taken along the IV-IV cross section line in Fig. 2. Fig. 5 is a view of the semiconductor device 1 as viewed along the VV cross section line in Fig. 2. Note that the inlet pipe 4A is not shown in Fig. 3, and the inlet pipe 4A and the outlet pipe 4B are not shown in Fig. 5.

[0015] The cooler 20 is a device that cools the semiconductor element 10 with a liquid refrigerant A. In other words, the semiconductor element 10 corresponds to an object to be cooled by the cooler 20. The type of liquid used as the refrigerant A is not limited.

[0016] 4, the cooler 20 of this embodiment includes a case body 200 having an opening 202, and a heat dissipation substrate 210 that closes the opening 202 of the case body 200. The semiconductor element 10 is mounted on a first main surface 210S1 of the heat dissipation substrate 210. The case body 200 is also referred to as a water jacket.

[0017] The heat dissipation substrate 210 is a flat plate-shaped member. The heat dissipation substrate 210 includes a first main surface 210S1 and a second main surface 210S2. The first main surface 210S1 and the second main surface 210S2 are main surfaces facing opposite each other. A material with high thermal conductivity is used as the main material of the heat dissipation substrate 210. Examples of such materials include metals such as copper and aluminum, or alloys. The semiconductor element 10 is bonded to the first main surface 210S1 of the heat dissipation substrate 210 using a bonding material whose main material is a highly thermally conductive material.

[0018] 4 , in the heat dissipation substrate 210, a fin portion 212 is provided on a second main surface 210S2 corresponding to the back side of the first main surface 210S1 within a range C1 facing the opening 202 of the case body 200. The fin portion 212 includes a plurality of fins 214 provided upright on the second main surface 210S2. The plurality of fins 214 are housed in the case body 200 by entering the interior of the case body 200 from the opening 202.

[0019] The shape of each of the multiple fins 214 may be appropriate, and may be, for example, pillar-shaped or plate-shaped. It is not necessary for all of the multiple fins 214 to have the same shape. Furthermore, the fin portion 212 may be integrally molded with the heat dissipation substrate 210, or may be separate from the heat dissipation substrate 210. In this embodiment, as shown in FIGS. 2 and 4 , the fins 214 are pillar-shaped. The arrangement of each of the multiple fins 214 may also be appropriate, and for example, the multiple fins 214 may be arranged in a lattice pattern or a staggered (zigzag) pattern in a plan view.

[0020] 4, the case body 200 is a so-called box-shaped member having a hollow three-dimensional shape. A material having high thermal conductivity is used as the main material of the case body 200. Typical examples of such materials include metals such as copper and aluminum, or alloys.

[0021] The case body 200 is configured by a first wall portion 200M1, a second wall portion 200M2, a third wall portion 200M3, a fourth wall portion 200M4, and a bottom surface portion 200M5. The first wall portion 200M1, the second wall portion 200M2, the third wall portion 200M3, and the fourth wall portion 200M4 are connected to form a rectangular frame shape in a plan view, thereby configuring the side walls of the case body 200.

[0022] 1, the first wall portion 200M1 is a plate-shaped portion that constitutes one side surface of the case body 200. The first wall portion 200M1 is provided with one inlet 204A for introducing the refrigerant A into the interior.

[0023] 2 and 5, the second wall portion 200M2 is a plate-shaped portion that constitutes one side surface of the case body 200. The second wall portion 200M2 faces the first wall portion 200M1. The second wall portion 200M2 is provided with one outlet 204B for discharging the refrigerant A from the inside.

[0024] In this embodiment, the inlet 204A and the outlet 204B are provided at positions directly opposite each other. That is, the outlet 204B is located on an extension line of the inlet 204A in the direction in which the inlet 204A penetrates the first wall portion 200M1. The direction of this extension line corresponds to the direction of a main line L, which will be described later.

[0025] The third wall portion 200M3 and the fourth wall portion 200M4 are surfaces facing each other and are each a plate-like portion that constitutes one side surface of the case body 200. As shown in Fig. 2, the third wall portion 200M3 and the fourth wall portion 200M4 intersect with the first wall portion 200M1 and the second wall portion 200M2.

[0026] Each of the first to fourth wall portions 200M1 to 200M4 may be flat, or may include curved surfaces, unevenness, etc. in part or in whole. Each of the first to fourth wall portions 200M1 to 200M4 may include two or more flat surfaces. When all of the first to fourth wall portions 200M1 to 200M4 are flat, the external shape of the case body 200 is a rectangular parallelepiped or a cube.

[0027] The bottom surface portion 200M5 is a plate-like portion that forms the bottom surface of the case body 200. The first wall portion 200M1, the second wall portion 200M2, the third wall portion 200M3, and the fourth wall portion 200M4 protrude upward from the bottom surface portion 200M5.

[0028] 4, the sealing surface 200S is the top surface of the case body 200. Specifically, the upper surface of the frame-shaped portion formed by the first wall portion 200M1, the second wall portion 200M2, the third wall portion 200M3, and the fourth wall portion 200M4 is the sealing surface 200S. Therefore, the sealing surface 200S is a plane substantially parallel to the bottom surface portion 200M5.

[0029] The sealing surface 200S is provided with the opening 202 described above. The sealing surface 200S is tightly attached to the second main surface 210S2 of the heat dissipation substrate 210 using fastening means such as screws. In addition to fastening means, appropriate joining means such as adhesive or welding may be used. The shape of the opening 202 in plan view is appropriate, and is typically rectangular. The opening area of ​​the opening 202 is also appropriate.

[0030] 5, the normal direction of the sealing surface 200S, which is the top surface, and the bottom surface portion 200M5 is defined as the "upper direction D." In this up-down direction D, the direction from the bottom surface portion 200M5 toward the sealing surface 200S is defined as the "upper direction Du," and the direction opposite to the "upper direction Du" is defined as the "lower direction Dd."

[0031] 1 , an inlet pipe 4A is connected to the inlet 204A, and an outlet pipe 4B is connected to the outlet 204B. At least one of the inlet pipe 4A and the outlet pipe 4B is connected to a pump that discharges or sucks refrigerant A. By operation of this pump, refrigerant A is introduced into the interior of the case body 200 through the inlet pipe 4A, flows inside the case body 200, and is discharged from the interior of the case body 200 through the outlet pipe 4B. The pump is not shown. As the refrigerant A flows inside the case body 200, it exchanges heat with the fin portion 212, thereby recovering the heat generated by the semiconductor element 10 and cooling the semiconductor element 10.

[0032] In this embodiment, as shown in Fig. 4, the fin portion 212 is provided on the second main surface 210S2 of the heat dissipation substrate 210 over at least the entire element cooling range C2. The element cooling range C2 is located on the back side of the element mounting range C3 on the first main surface 210S1, i.e., the range located directly below the element mounting range C3 in a cross-sectional view. The element mounting range C3 is a range in which a semiconductor element 10 can be mounted. By providing the fin portion 212 over substantially the entire element cooling range C2, the heat generated by the semiconductor element 10 mounted in the element mounting range C3 is efficiently recovered into the refrigerant A through the fin portion 212 directly below it.

[0033] 1, the planar shape of the element mounting area C3 in this embodiment is a shape that extends in the direction of the long axis K. When multiple semiconductor elements 10 are mounted on the heat dissipation substrate 210, the multiple semiconductor elements 10 are mounted in a state of being aligned in the direction of the long axis K of the element mounting area C3. In other words, the long axis K of the element mounting area C3 can also be said to be the direction in which the multiple semiconductor elements 10 are aligned.

[0034] On the other hand, assuming that no structures exist inside the case body 200, as shown in Fig. 2, the refrigerant A flows along a main line L, which is a line that linearly connects the inlet 204A and the outlet 204B. The main line L is an imaginary line that extends from the first wall portion 200M1 toward the second wall portion 200M2. The main line L can also be described as a line that is parallel to the normal to the first wall portion 200M1 or the second wall portion 200M2.

[0035] 1 and 2, this main line L does not coincide with the major axis K of the element mounting area C3, but intersects with this major axis K. In this embodiment, the angle at which the major axis K of the element mounting area C3 and the main line L intersect is approximately 90 degrees.

[0036] Therefore, when the coolant A flows along the main line L, at an end C3A on the long axis K in the element mounting range C3, the flow rate of the coolant A flowing directly below the end C3A is smaller than in the vicinity of the main line L, and the amount of heat recovered is also smaller. As a result, in the element mounting range C3, the cooling effect weakens as the distance from the main line L increases, causing the temperature of the semiconductor elements 10 to rise, resulting in temperature differences between the semiconductor elements 10.

[0037] Therefore, in order to suppress the temperature difference between the semiconductor elements 10, the cooler 20 of this embodiment is provided with a convex structure 240 on the bottom surface 200M5 of the case body 200, as shown in Fig. 5. The structure 240 is a structure that takes in the refrigerant A that flows in from the inlet 204A, guides the taken-in refrigerant A in a guide direction E, and causes it to flow out from a position corresponding to the fin portion 212. The guide direction E of this structure 240 is approximately parallel to the direction of the major axis K of the element mounting area C3, as shown in Fig. 2.

[0038] By guiding the coolant A in the guiding direction E, the flow rate of the coolant A flowing directly below the end C3A of the element mounting range C3 increases. The increased flow rate of the coolant A also increases the amount of heat recovered, and as a result, the temperature difference between the semiconductor elements 10 in the element mounting range C3 is suppressed. In other words, the temperature of the semiconductor element 10 with the highest temperature is reduced. Furthermore, because the coolant A is guided in the guiding direction E through the inside of the structure 240, the coolant A can be reliably guided in the guiding direction E compared to a configuration in which the coolant A flowing along the surface of the structure 240 is controlled by, for example, the surface shape of the structure 240.

[0039] The structure 240 will now be described in more detail.

[0040] Fig. 6 is a perspective view of the case body 200 viewed from above, and Fig. 7 is a plan view of the case body 200 viewed from above. Fig. 8 is a diagram showing a cross section of the case body 200 taken along the VIII-VIII cross section line in Fig. 6. Fig. 9 is a diagram showing the case body 200 viewed from the IX-IX cross section line in Fig. 6.

[0041] 6 and 7, the structure 240 includes a main body 242 that is generally rod-shaped in plan view and extends between the third wall 200M3 and the fourth wall 200M4 in the direction of the major axis K of the element mounting range C3. Both ends of the main body 242 are connected to the inner surfaces of the third wall 200M3 and the fourth wall 200M4 without any gaps.

[0042] The main body 242 is mainly made of a material having high thermal conductivity, similar to the case body 200. As shown in Fig. 9, the cross-sectional shape of the main body 242 is trapezoidal. Specifically, the main body 242 has a first opposing surface 242M1, a second opposing surface 242M2, and an upper surface 242M3.

[0043] The first opposing surface 242M1 is a surface facing the inlet 204A, and the second opposing surface 242M2 is a surface facing the outlet 204B. The upper surface 242M3 is a surface connected to the first opposing surface 242M1 and the second opposing surface 242M2. Therefore, the upper surface 242M3 faces the fin portion 212 of the heat dissipation substrate 210.

[0044] The first opposing surface 242M1 is inclined in the upward direction Du in a direction away from the inlet 204A. In other words, the first opposing surface 242M1 is an inclined surface inclined at an acute angle with respect to the bottom surface 200M5. The top surface 242M3 is a plane substantially parallel to the second main surface 210S2 of the heat dissipation substrate 210 and is located near the fin portion 212 in the vertical direction D without contacting the fin portion 212. The second opposing surface 242M2 is inclined in the downward direction Dd in a direction approaching the outlet 204B. In other words, the second opposing surface 242M2 is an inclined surface inclined at an acute angle with respect to the bottom surface 200M5. Note that the second opposing surface 242M2 does not necessarily have to be an inclined surface.

[0045] In this embodiment, an intake hole 244 is provided in the first opposing surface 242M1 at a position directly opposite the inlet 204A. In other words, the intake hole 244 is provided on the above-mentioned main line L, which corresponds to an extension of the penetration direction of the inlet 204A. The intake hole 244 is a horizontal hole for taking in the refrigerant A that has flowed in from the inlet 204A into the interior of the structure 240. The intake hole 244 is a horizontal hole whose depth direction is perpendicular to the up-down direction D.

[0046] On the other hand, as shown in FIG. 7 , a pair of outlet holes 246 are provided on either side of the main line L in the upper surface 242M3. Each of the pair of outlet holes 246 is a vertical hole for allowing the refrigerant A taken into the interior of the structure 240 to flow out from the upper surface 242M3. The vertical hole has a depth direction in the up-down direction D. More specifically, as shown in FIGS. 8 and 9 , each of the pair of outlet holes 246 communicates with the intake hole 244. As shown in FIGS. 7 and 8 , each of the pair of outlet holes 246 is a hole shaped to extend in the guiding direction E in a plan view, i.e., an elongated hole. In this embodiment, the guiding direction E is approximately parallel to the major axis K of the element mounting area C3, as described above.

[0047] In this embodiment, the structure 240 is integrally molded with the case body 200. For example, die casting is used to integrally mold the structure 240 and the case body 200. The outflow hole 246, which is a vertical hole, is formed by a mold used for integral molding. Furthermore, the intake hole 244, which is a horizontal hole, is formed by a tool inserted coaxially into the inlet 204A after the inlet 204A has been formed by tapping or the like. According to this manufacturing method, the only additional processing required to provide the structure 240 in the manufacturing process of the case body 200 is the processing to form the intake hole 244 in the structure 240, thereby suppressing increases in processing costs.

[0048] Next, the flow of the refrigerant A will be described in detail.

[0049] Fig. 10 is a diagram schematically illustrating the flow of refrigerant A as viewed from above case body 200, and Fig. 11 is a diagram schematically illustrating the flow of refrigerant A in a cross section of case body 200. As shown in Fig. 11 , inside case body 200, refrigerant A introduced through inlet 204A is taken into the interior through inlet hole 244 of structure 240. As described above, inlet hole 244 is located on an extension line of the penetration direction of inlet 204A, and therefore refrigerant A is smoothly taken into inlet hole 244. The opening diameter of inlet hole 244 is set appropriately depending on the results of a pressure loss simulation, which will be described later.

[0050] Refrigerant A taken in through inlet hole 244 flows toward each of a pair of outlet holes 246 communicating with inlet hole 244. Then, as shown in FIG. 10 , refrigerant A moves through each of the pair of outlet holes 246 along guide direction E and flows out from upper surface 242M3. As refrigerant A moves in guide direction E, refrigerant A spreads in the direction of major axis K on upper surface 242M3, ensuring a flow rate of refrigerant A even at locations away from main line L in the direction of major axis K of element mounting range C3. Refrigerant A flowing out from outlet hole 246 flows along upper surface 242M3 toward outlet 204B while collecting heat from fin portion 212, and is discharged from outlet 204B.

[0051] 2, in this embodiment, the pair of outlet holes 246 are arranged immediately below an area of ​​the element mounting area C3 that is closer to the inlet 204A than the outlet 204B, i.e., upstream of the flow of the coolant A on the upper surface 242M3. With the above configuration, the coolant A can flow over almost the entire area on the upper surface 242M3 that is immediately below the semiconductor element 10. Therefore, the heat generated by the semiconductor element 10 can be recovered more efficiently, and cooling performance can be improved.

[0052] 11 , a portion of the refrigerant A introduced from the inlet 204A flows along the first opposing surface 242M1 of the main body 242 to the upper surface 242M3. In a plan view, the flow rate of the refrigerant A is high near the main line L and decreases as it moves away from the main line L in the direction of the major axis K of the element mounting range C3, so that the cooling performance near the main line L is relatively high.

[0053] On the other hand, since the pair of outlet holes 246 are arranged on either side of the main line L, the flow rate of the refrigerant A flowing out from the outlet holes 246 is lowest near the main line L, and the cooling performance near the main line L is relatively low in the direction of the long axis K of the element mounting range C3.

[0054] As a result, in the direction of the long axis K of the element mounting range C3, a balance is achieved between the cooling performance of the refrigerant A flowing along the first opposing surface 242M1 and the cooling performance of the refrigerant A flowing out from each of the pair of outlet holes 246.

[0055] Fig. 12 is a diagram showing simulation results of the temperatures of six semiconductor elements 10 mounted on the cooler 20, and Fig. 13 is a diagram showing simulation results of pressure loss in the cooler 20. In Fig. 13, the semiconductor element numbers indicate the order of the six semiconductor elements 10 when counted from one end of the array. In Fig. 13, the pressure loss of the refrigerant A is the difference between the pressure at the inlet 204A and the pressure at the outlet 204B. Furthermore, in Figs. 12 and 13, the comparative configuration is a configuration in which the inlet hole 244 and the pair of outlet holes 246 are not provided in the structure 240, as compared to the configuration of the semiconductor device 1 of this embodiment.

[0056] As shown in FIG. 12, it can be seen that the structure 240 guides the coolant A in the guide direction E, and therefore the temperature difference between the six semiconductor elements 10 in the element mounting range C3 is smaller than in the comparative configuration.

[0057] 13, inside the case body 200, a flow path that passes through the inside of the structure 240 and reaches the upper surface 242M3 of the structure 240 is formed by the inlet hole 244 and the pair of outlet holes 246, and it can be seen that the pressure loss is reduced compared to a comparative configuration that does not have this path. The reduced pressure loss prevents the refrigerant A from accumulating in the cooler 20, thereby improving the cooling performance.

[0058] As described above, the cooler 20 of this embodiment includes the heat dissipation substrate 210 having one or more semiconductor elements 10 mounted on the first main surface 210S1, and the case body 200 that is in close contact with the second main surface 210S2 of the heat dissipation substrate 210 and houses the fin portion 212 provided on the second main surface 210S2. The case body 200 includes a first wall portion 200M1 provided with an inlet 204A through which the refrigerant A is introduced into the case body 200, and a second wall portion 200M2 facing the first wall portion 200M1 and provided with an outlet 204B through which the refrigerant A is discharged from the inside of the case body 200. The case body 200 is provided with a structure 240 that takes in the refrigerant A that has flowed in from the inlet 204A, guides the refrigerant A in a guide direction E that intersects with the main line L that linearly connects the inlet 204A and the outlet 204B, and causes the refrigerant A to flow out from a position corresponding to the fin portion 212.

[0059] According to this configuration, since the refrigerant A is guided in the guiding direction E, the flow rate of the refrigerant A flowing there increases even in locations away from the main line L in a direction intersecting the main line L, improving the cooling performance at those locations. As a result, the temperature difference between the semiconductor elements 10 is suppressed, and the temperature of the semiconductor element 10 with the highest temperature is reduced. Furthermore, since the refrigerant A is guided in the guiding direction E through the inside of the structure 240, the refrigerant A can be reliably guided in the guiding direction E compared to a configuration in which the refrigerant A flowing along the surface of the structure 240 is controlled by, for example, the surface shape of the structure 240.

[0060] In the cooler 20 of this embodiment, the structure 240 includes a first opposing surface 242M1 that faces the inlet 204A of the first wall portion 200M1. The first opposing surface 242M1 is provided with an inlet hole 244 that takes in the refrigerant A that flows in from the inlet 204A, on an extension of the penetration direction of the inlet 204A. With this configuration, the refrigerant A that flows in from the inlet 204A can be smoothly taken in from the inlet hole 244. In addition, the inlet hole 244 can be easily formed using a tool inserted through the inlet 204A.

[0061] In the cooler 20 of this embodiment, the structure 240 includes an upper surface 242M3 facing the fin portion 212 of the second main surface 210S2 of the heat dissipation substrate 210. The upper surface 242M3 is provided with one or more outlet holes 246, which are opening-shaped holes extending in a guide direction E intersecting the main line L in a plan view, and which allow the refrigerant A taken in through the inlet hole 244 to flow out. With this configuration, the refrigerant A can be reliably guided in the guide direction E intersecting the main line L and can flow out to a location corresponding to the fin portion 212.

[0062] In the cooler 20 of this embodiment, the number of semiconductor elements 10 is two or more, and the semiconductor elements 10 are mounted along the guide direction E. With this configuration, the temperature difference between the semiconductor elements 10 due to uneven cooling performance is suppressed.

[0063] In the cooler 20 of the present embodiment, the number of outlet holes 246 is two, and the two outlet holes 246 are provided on the upper surface 242M3 on both sides of the inlet hole 244. With this configuration, in the guide direction E intersecting the main line L, a balance is achieved between the cooling performance of the refrigerant A flowing along the first opposing surface 242M1 and the cooling performance of the refrigerant A flowing out from each outlet hole 246.

[0064] In the cooler 20 of this embodiment, the outlet holes 246 are provided on the upper surface 242M3 upstream of the flow of the coolant A. With this configuration, the coolant A can flow over substantially the entire area directly below the semiconductor element 10, so that the heat generated by the semiconductor element 10 can be recovered more efficiently, thereby improving cooling performance.

[0065] 2. Modifications Examples of modifications that can be added to the above-described embodiment are given below. Two or more of the following examples may be arbitrarily selected and combined as long as they are not mutually contradictory. In the drawings referred to in the following description, elements similar to those described in the embodiment are designated by the same reference numerals.

[0066] (Variation 1) Fig. 14 is a diagram showing an example of the configuration of a case body 200 according to a first variation of the present disclosure. As shown in Fig. 14, in the structure 240 of the case body 200, the first opposing surface 242M1 may not be an inclined surface, but may be a surface that is approximately perpendicular to the bottom surface 200M5. Furthermore, the first opposing surface 242M1 may be an inclined surface that is inclined at an obtuse angle with respect to the bottom surface 200M5. The inclination angle of the first opposing surface 242M1 is set appropriately depending on the pressure loss and unevenness in cooling performance within the element mounting range C3, as described above.

[0067] 14, the second opposing surface 242M2 of the structure 240 may not be an inclined surface but may be a surface that is approximately perpendicular to the bottom surface portion 200M5. The second opposing surface 242M2 may be an inclined surface that is inclined at an obtuse angle with respect to the bottom surface portion 200M5.

[0068] 15 is an exploded perspective view showing an example of the configuration of case body 200 according to a second modification of the present disclosure. Structural body 240 is not limited to being integrally molded with case body 200, and may be a separate body from case body 200, as shown in FIG.

[0069] (Variation 3) In the above-described embodiment, the guiding direction E in which the outflow holes 246 extend may be any direction that intersects with the main line L, and does not necessarily have to coincide with the direction of the long axis K of the element mounting area C3 or the direction in which the semiconductor elements 10 are arranged. In other words, the guiding direction E may not be a direction perpendicular to the main line L, but may be a direction that intersects with the main line L at an acute or obtuse angle.

[0070] (Variation 4) In the above-described embodiment, the main line L is located at approximately the center of the cooler 20 in the direction of the long axis K, and the outflow holes 246 are provided on both sides of the main line L. However, when the main line L is located away from approximately the center of the cooler 20 in the direction of the long axis K, the outflow holes 246 may be provided on either side of the main line L.

[0071] (Variation 5) In the above-described embodiment, the shape of the outflow hole 246 on the upper surface 242M3 is a shape in which the width in the direction of the main line L is constant at any point in the guide direction E. However, the width does not have to be constant. For example, the width may increase or decrease as the distance from the main line L in the guide direction E increases.

[0072] (Variation 6) In the above-described embodiment, the inlet 204A of the case body 200 and the intake hole 244 of the structure 240 may be connected by a tube. This tube may be, for example, the tip of the inlet pipe 4A.

[0073] (Variation 7) In the above-described embodiment, a configuration was illustrated in which the first opposing surface 242M1 of the structure 240 (main body portion 242) faces the inner wall surface of the first wall portion 200M1 with a gap therebetween. However, as illustrated in Fig. 16, the first wall portion 200M1 and the structure 240 may be formed integrally. That is, the first opposing surface 242M1 is not formed on the structure 240, and the upper surface 242M3 is directly connected to the inner wall surface of the first wall portion 200M1. The intake hole 244 of the structure 240 directly communicates with the inlet 204A of the first wall portion 200M1.

[0074] In the above configuration, refrigerant A introduced from inlet 204A is directly taken into the interior of structure 240 through inlet holes 244, and after diffusing in guide direction E inside structure 240, flows out from each outlet hole 246. Refrigerant A flowing out of structure 240 passes through the space between upper surface 242M3 and heat dissipation substrate 210, and is discharged from outlet 204B of second wall portion 200M2. The configuration of FIG. 16 also achieves the same effects as the above-described embodiment.

[0075] (Variant 8) In the above-described embodiment, an example was given in which the inlet 204A is provided in the first wall portion 200M1 and the outlet 204B is provided in the second wall portion 200M2, but the positions of the inlet 204A and the outlet 204B are not limited to the above example.

[0076] 17 , for example, an inlet 204A may be formed in a region of the bottom surface 200M5 that is located between the first wall portion 200M1 and the structure 240 in a plan view. An inlet pipe 4A that communicates with the inlet 204A is connected to the bottom surface 200M5. A portion of the refrigerant A that passes through the inlet 204A is taken in by the inlet hole 244 and flows out through each outlet hole 246. Another portion of the refrigerant A that passes through the inlet 204A flows along the first opposing surface 242M1 to the upper surface 242M3.

[0077] 17 , an outlet 204B may be formed in a region of the bottom surface 200M5 that is located between the second wall portion 200M2 and the structure 240 in a plan view. An outlet pipe 4B that communicates with the outlet 204B is connected to the bottom surface 200M5. The outlet 204B is located in the direction of the main line L relative to the inlet 204A. That is, the configuration in which the inlet 204A and the outlet 204B are located on the main line L in a plan view is the same in both the above-described embodiment and the configuration in FIG. 17 .

[0078] As described above, the positions at which the inlet 204A and the outlet 204B are formed can be changed as desired. However, according to the configuration in which the inlet 204A is formed in the first wall portion 200M1 as in the above-described embodiment, the intake hole 244 can be provided at a position directly opposite the inlet 204A. This has the advantage that the refrigerant A introduced through the inlet 204A can be efficiently supplied to the intake hole 244. Note that in the configuration of FIG. 16 in which the first wall portion 200M1 and the structure 240 are continuous, the inlet 204A and the outlet 204B may be formed in the bottom surface portion 200M5, as in FIG. 17 .

[0079] (Modification 9) In the above-described embodiment, a configuration in which a plurality of semiconductor elements 10 are mounted on the cooler 20 has been exemplified, but the configuration in which each semiconductor element 10 is mounted on the cooler 20 is not limited to the above example. For example, as exemplified in Fig. 18 , a semiconductor module 30 (30U, 30V, 30W) including a plurality of semiconductor elements 10 may be mounted on the cooler 20.

[0080] 18 illustrates a configuration in which three semiconductor modules 30 (30U, 30V, 30W) are mounted on the first main surface 210S1 of the heat dissipation substrate 210. Specifically, the three semiconductor modules 30 are arranged along the long axis K at intervals from each other.

[0081] Three semiconductor modules 30 constitute a power conversion device 40 as shown in FIG. 19 , for example. The power conversion device 40 in FIG. 19 is a three-phase inverter circuit that converts DC power into AC power. The semiconductor module 30U corresponds to the U phase, the semiconductor module 30V corresponds to the V phase, and the semiconductor module 30W corresponds to the W phase. Note that the power conversion device 40 is not limited to an inverter circuit. For example, the power conversion device 40, such as a converter circuit or a chopper circuit, may be constituted by the semiconductor modules 30.

[0082] As illustrated in FIG. 18 , each semiconductor module 30 includes three upper arm elements 10u and three lower arm elements 10d. As illustrated in FIG. 19 , each upper arm element 10u is a semiconductor element including, for example, a switching device and a diode. The single upper arm element 10u illustrated in FIG. 19 is actually configured with three elements connected in parallel, as illustrated in FIG. 18 . Similarly, each lower arm element 10d is a semiconductor element including, for example, a switching device and a diode. The single lower arm element 10d illustrated in FIG. 19 is actually configured with three elements connected in parallel, as illustrated in FIG. 18 . As illustrated in FIG. 18 , the three upper arm elements 10u in each semiconductor module 30 are arranged in one region on either side of the longitudinal axis K, and the three lower arm elements 10d are arranged in the other region on either side of the longitudinal axis K.

[0083] As described above, even in the configuration of Fig. 18 , a plurality of semiconductor elements (upper arm element 10u and lower arm element 10d) are mounted on cooler 20. Note that although three semiconductor modules 30 are illustrated in Fig. 18 , as illustrated in Fig. 20 , a single semiconductor module 30 constituting power conversion device 40 illustrated in Fig. 19 may be mounted on cooler 20.

[0084] 18 illustrates an example in which a pair of outlet holes 246 is located between the arrangement of the plurality of semiconductor modules 30 and the first wall portion 200M1 of the case body 200 in a plan view, but the positional relationship between the plurality of semiconductor modules 30 and the pair of outlet holes 246 is not limited to this example. For example, as illustrated in FIG. 21 , a pair of outlet holes 246 may be formed between the arrangement of the plurality of upper arm elements 10u and the arrangement of the plurality of lower arm elements 10d. In the configuration illustrated in FIG. 21 , the plurality of lower arm elements 10d are cooled by the refrigerant A that reaches the upper surface 242M3 along the first opposing surface 242M1 of the structure 240. On the other hand, the plurality of upper arm elements 10u are cooled by the refrigerant A that reaches the upper surface 242M3 from the first opposing surface 242M1 and the refrigerant A that flows from the interior of the structure 240 through the outlet holes 246 and flows out onto the upper surface 242M3.

[0085] The semiconductor modules 30 (30U, 30V, 30W), the upper arm element 10u, the lower arm element 10d, and the semiconductor element 10 are examples of the "semiconductor element" in the present disclosure.

[0086] (Variation 10) As illustrated in Figure 22, a recess 215 may be formed in the first main surface 210S1 of the heat dissipation substrate 210. Figure 23 is a cross-sectional view taken along the XXIII-XXIII cross-sectional line in Figure 22. As illustrated in Figures 22 and 23, the recess 215 in the first main surface 210S1 is a rectangular depression whose outer dimensions are slightly larger than the arrangement of the three semiconductor modules 30. The three semiconductor modules 30 are mounted on the cooler 20 while housed in the recess 215. The depth of the recess 215 is less than the height of the semiconductor modules 30.

[0087] According to the configuration of FIG. 22, the side surfaces of the semiconductor modules 30 come into contact with the inner wall surfaces of the recesses 215, thereby positioning the semiconductor modules 30 in a plane parallel to the first main surface 210S1.

[0088] (Modification 11) In the above-described embodiment, the semiconductor element 10 is bonded to the first main surface 210S1 of the heat dissipation substrate 210, but the configuration for mounting the semiconductor element 10 on the heat dissipation substrate 210 is not limited to the above example. For example, a plurality of semiconductor modules 30 may be mounted on the cooler 20 using the configuration illustrated in FIG.

[0089] 24 includes a plurality of semiconductor modules 30 (30U, 30V, 30W) and a cooler 20, as well as a plurality of connecting conductors 31, a plurality of output conductors 32, a capacitor 35, and a holding member 36. Two connecting conductors 31 and one output conductor 32 are provided for each of the plurality of semiconductor modules 30.

[0090] The capacitor 35 is a passive component used, for example, to smooth the voltage in the power conversion device 40, and is fixed to a housing (not shown). Each connecting conductor 31 is a conductor for electrically connecting the semiconductor device 1 and the capacitor 35. The connecting conductor 31 is, for example, a bus bar.

[0091] Each output conductor 32 is a conductor for electrically connecting the semiconductor device 1 to an external device (not shown) such as an electric motor. The output conductors 32 are, for example, bus bars. The holding member 36 is a structure for supporting and fixing the plurality of output conductors 32 to a housing (not shown). In a plan view, the cooler 20 is located between the capacitor 35 and the plurality of output conductors 32.

[0092] Each semiconductor module 30 has two connection terminals 33 and one output terminal 34. Each connection terminal 33 is electrically connected to a capacitor 35 by being joined to a connection conductor 31. The output terminal 34 is electrically connected to an external device such as an electric motor by being joined to an output conductor 32.

[0093] By joining the connection terminals 33 to the connection conductors 31 and by joining the output terminals 34 to the output conductors 32, each semiconductor module 30 is supported between the capacitors 35 and the holding member 36. Specifically, each semiconductor module 30 is supported between the capacitors 35 and the holding member 36 with its bottom surface in contact with the first main surface 210S1 of the heat dissipation substrate 210.

[0094] 24 , each semiconductor module 30 (semiconductor element) is supported by a support member such as a capacitor 35 or a holding member 36, thereby positioning each semiconductor module 30 in a plane parallel to the first main surface 210S1, and the semiconductor module 30 is mounted on the cooler 20. Therefore, it is not necessary for the semiconductor module 30 to be directly bonded to the first main surface 210S1. Note that in the configuration of FIG. 24 , each semiconductor module 30 may be bonded to the first main surface 210S1 by a bonding material primarily made of a highly thermally conductive material.

[0095] (Variant 12) In the above-described embodiment, an example was given of a case body 200 that is rectangular in plan view, in which the first wall portion 200M1 and the second wall portion 200M2 form the long sides of the rectangle, and the third wall portion 200M3 and the fourth wall portion 200M4 form the short sides of the rectangle, but the shape of the case body 200 is not limited to the above example.

[0096] 25 , the first wall 200M1 and the second wall 200M2 may form the short sides of a rectangle, and the third wall 200M3 and the fourth wall 200M4 may form the long sides of the rectangle. The inlet 204A is provided in the first wall 200M1, and the outlet 204B is provided in the second wall 200M2. Therefore, the refrigerant A that flows into the case body 200 from the inlet 204A flows along the longitudinal direction of the case body 200. The guide direction E corresponds to the short side direction of the case body 200.

[0097] The plurality of semiconductor modules 30 (30U, 30V, 30W) mounted on the first main surface 210S1 of the heat dissipation substrate 210 are arranged at intervals from one another along the longitudinal direction of the case body 200. In the configuration of Fig. 25, a pair of outlet holes 246 is formed between the semiconductor module 30U and the first wall portion 200M1 in a plan view. Therefore, the plurality of semiconductor modules 30 are cooled by the refrigerant A that passes from the inside of the structure 240 through the outlet holes 246 and reaches the upper surface 242M3.

[0098] 25 illustrates a configuration in which a pair of outlet holes 246 are formed on the upstream side of semiconductor module 30U, but the positions of the pair of outlet holes 246 are not limited to the above example. For example, as illustrated in FIG. 26, a pair of outlet holes 246 may be formed between semiconductor module 30V and semiconductor module 30W in a plan view. Alternatively, a pair of outlet holes 246 may be formed between semiconductor module 30U and semiconductor module 30V in a plan view.

[0099] 27 , multiple pairs of outflow holes 246 (2461, 2462, 2463) may be formed in the structure 240. Specifically, a pair of outflow holes 246 may be individually formed for each semiconductor module 30. In the configuration of FIG. 27 , multiple pairs of outflow holes 246 are formed at intervals along the direction in which the multiple semiconductor modules 30 are arranged.

[0100] Specifically, the pair of outlet holes 2461 are located between the semiconductor module 30U and the first wall portion 200M1 in a plan view. The pair of outlet holes 2462 are located between the semiconductor module 30U and the semiconductor module 30V in a plan view. The pair of outlet holes 2463 are located between the semiconductor module 30V and the semiconductor module 30W in a plan view.

[0101] In the above configuration, semiconductor module 30U is cooled by refrigerant A flowing out from each outlet hole 2461. Semiconductor module 30V is cooled by refrigerant A flowing out from each outlet hole 2461 and each outlet hole 2462. Semiconductor module 30W is cooled by refrigerant A flowing out from each outlet hole 2461, each outlet hole 2462, and each outlet hole 2463.

[0102] Outlet holes 2461, 2462, and 2463 may have the same shape or size or may differ from one another. For example, an arrangement is envisioned in which outlet holes 246 located further downstream in the direction of refrigerant A have larger opening areas (e.g., widths of outlet holes 246). Specifically, outlet hole 2462 has a larger area than outlet hole 2461, and outlet hole 2463 has a larger area than outlet hole 2462. With the above configuration, it is easy to ensure the flow rate of refrigerant A even for outlet holes 246 located further downstream.

[0103] DESCRIPTION OF SYMBOLS 1... Semiconductor device, 4A... Inlet pipe, 4B... Discharge pipe, 10... Semiconductor element, 20... Cooler, 200... Case body, 200M1... First wall part, 200M2... Second wall part, 200 M3...Third wall part, 200M4...Fourth wall part, 200M5...Bottom part, 200S...Sealing surface, 202...Opening part, 204A...Inlet port, 204B...Outlet port, 210...Radiation board, 210S1...first main surface, 210S2...second main surface, 212...fin portion, 214...fin, 240...structure, 242...main body portion, 242M1...first opposing surface, 242M3...upper surface, 244...intake hole, 246...outlet hole, A...refrigerant, C3...element mounting range, D...vertical direction, Dd...downward direction, Du...upward direction, E...guiding direction, K...long axis, L...main line.

Claims

1. A cooler comprising: a heat dissipation substrate including a first main surface on which one or more semiconductor elements are mounted and a second main surface provided with a fin portion; a case body in close contact with the second main surface and accommodating the fin portion; and a structure, wherein the case body includes a first wall portion, a second wall portion opposing the first wall portion, an inlet port for introducing a refrigerant into the interior of the case body, and an outlet port located relative to the inlet port in the direction of a main line from the first wall portion to the second wall portion and for discharging the refrigerant from the interior of the case body, wherein the structure takes in the refrigerant that has flowed in from the inlet port, guides the refrigerant in a guide direction that intersects with the main line, and allows it to flow out from a position corresponding to the fin portion.

2. The cooler according to claim 1, wherein the inlet is provided in the first wall portion, and the outlet is provided in the second wall portion.

3. A cooler as claimed in claim 2, wherein the structure includes a first opposing surface facing the first wall portion, and an intake hole for taking in the refrigerant flowing in from the inlet is provided on an extension of the penetrating direction of the inlet.

4. A cooler as claimed in claim 3, wherein the structure includes an upper surface opposite the second main surface, and the upper surface is provided with one or more outlet holes which are holes shaped to extend in the guide direction in a plan view and which allow the refrigerant taken in through the inlet hole to flow out.

5. The cooler according to claim 4, wherein the one or more semiconductor elements are two or more semiconductor elements, and the two or more semiconductor elements are mounted along the guide direction.

6. A cooler as claimed in claim 4 or claim 5, wherein the one or more outlet holes are two outlet holes, the main line is a line linearly connecting the inlet and the outlet, and the two outlet holes are provided on both sides of the main line on the upper surface.

7. A cooler according to any one of claims 4 to 6, wherein the one or more outlet holes are provided on the upper surface on an upstream side of the flow of the refrigerant.

8. A semiconductor device comprising: one or more semiconductor elements; and a cooler for cooling the semiconductor elements, wherein the cooler comprises: a heat dissipation substrate including a first main surface on which the semiconductor elements are mounted and a second main surface on which a fin portion is provided; a case body in close contact with the second main surface and accommodating the fin portion; and a structure, wherein the case body includes: a first wall portion; a second wall portion opposing the first wall portion; an inlet port for introducing a refrigerant into the inside of the case body; and an outlet port located relative to the inlet port in the direction of a main line from the first wall portion to the second wall portion and for discharging the refrigerant from the inside of the case body, wherein the structure takes in the refrigerant that has flowed in from the inlet port, guides the refrigerant in a guide direction intersecting the main line, and allows it to flow out from a position corresponding to the fin portion.