Semiconductor device

Abstract

To ensure rigidity and to ensure cooling performance. A semiconductor device (1) includes an insulating substrate (14) having a first surface and a second surface on the opposite side of the first surface, semiconductor elements (12, 13) mounted on the first surface of the insulating substrate, and a cooler (20) for cooling the semiconductor elements. The cooler includes a heat dissipation substrate (21) having a joint surface and a heat dissipation surface on the opposite side of the joint surface, the joint surface being joined to the second surface of the insulating substrate, a plurality of heat dissipation fins (22) provided on the heat dissipation surface of the heat dissipation substrate, a reinforcing plate (30) disposed so as to cover the plurality of heat dissipation fins, the reinforcing plate being joined to the top ends of the plurality of heat dissipation fins, and a cooling housing (24) having a recess that houses the plurality of heat dissipation fins and the reinforcing plate. A gap (D2) between the plurality of heat dissipation fins is larger than a gap (D1) between the reinforcing plate and a bottom surface of the recess.

Description

TECHNICAL FIELD

[0001] The present application relates to a semiconductor device provided with a cooler for cooling a semiconductor element. BACKGROUND

[0002] In a hybrid vehicle, an electric vehicle, a power conversion device is used for variably driving a motor. The power conversion device uses a semiconductor assembly (power semiconductor assembly) provided with a plurality of power semiconductor elements. Generally, the power semiconductor elements generate heat when controlling a large current, and the amount of heat generated increases with miniaturization and high output of the power conversion device.

[0003] In the past, in order to cool the power semiconductor assembly, a semiconductor device provided with a refrigerant-type cooler has been proposed. For example, in such a refrigerant-type cooler, a heat dissipation substrate made of metal is provided which is joined to a face of an insulating substrate on which a power semiconductor element is mounted, on the side opposite the semiconductor assembly; a heat dissipation fin is formed in one piece with the heat dissipation substrate; and a box-shaped cooling housing which houses the heat dissipation fin and is liquid-tightly mounted to the heat dissipation substrate. By causing a cooling medium pressurized by an external pump to flow in a flow path in the cooling housing, the heat generated by the power semiconductor element is dissipated to the cooling medium via the heat dissipation fin.

[0004] Specifically, as such a semiconductor device, for example, in Patent Literature 1, a technology is disclosed in which a power semiconductor element is fixed to one face of a cooling fin base, and a plurality of heat dissipation fins are formed on the other face of the cooling fin base. In Patent Literature 1, a box-shaped cooling container is disposed on the other face side of the cooling fin base so as to cover the plurality of heat dissipation fins. A space that becomes a refrigerant flow path is formed by the gap between the inner surface side of the cooling container, the other face side of the cooling fin base, and the plurality of heat dissipation fins.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2016-92209 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In addition, in the above-described refrigerant flow path, from the viewpoint of heat exchange, it is preferable that the refrigerant flow in the gaps between the plurality of fins. However, the gaps between the fins have a tendency that pressure loss is high. Therefore, the refrigerant has a tendency to preferentially flow in the gaps between the top ends of the fins and the bottom surface of the cooling container, which have lower pressure loss than the gaps between the fins. As a result, the flow rate of the refrigerant cannot be sufficiently ensured on the inner side of the plurality of fins, and the cooling effect of the module can be uneven.

[0010] In addition, the cooling fin base provided with the plurality of fins can be thermally deformed in the manufacturing process. In consideration of the thermal deformation, the above-described gaps are provided between the top ends of the fins and the bottom surface of the cooling container. In order to suppress the thermal deformation and ensure rigidity, it is considered to increase the thickness of the cooling fin base. However, the increase in the thickness results in an increase in thermal resistance, and as a result, the thermal conductivity of the cooler itself can be affected.

[0011] The present application is made in view of this, and an object thereof is to provide a semiconductor device capable of ensuring rigidity and ensuring cooling performance.

[0012] Solution to the problem

[0013] The semiconductor device of the present embodiment includes an insulating substrate having a first surface and a second surface on the side opposite to the first surface, a semiconductor element mounted on the first surface of the insulating substrate, and a cooler for cooling the semiconductor element, in which the cooler includes a heat dissipation substrate having a bonding surface and a heat dissipation surface on the side opposite to the bonding surface, the bonding surface being bonded to the second surface of the insulating substrate, a plurality of fins provided on the heat dissipation surface of the heat dissipation substrate, a reinforcing plate disposed so as to cover the plurality of fins, the top ends of the plurality of fins being bonded to the reinforcing plate, and a cooling housing having a recess that accommodates the plurality of fins and the reinforcing plate, the gaps between the plurality of fins being larger than the gaps between the reinforcing plate and the bottom surface of the recess.

[0014] Effects of the invention

[0015] According to the present application, it is possible to ensure rigidity and ensure cooling performance. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is an exploded perspective view of the semiconductor device of the present embodiment.

[0017] Figure 2 in Figure 2 A and Figure 2 B is a plan view of the semiconductor device of the present embodiment and the cooling housing of the semiconductor device.

[0018] Figure 3 is an explanatory view of a heat dissipation fin and a reinforcing plate of the semiconductor device of the present embodiment provided to a heat dissipation substrate.

[0019] Figure 4 in Figure 4 A and Figure 4 B are a perspective view of a cooling base of the present embodiment and a cross-sectional view showing the flow of a cooling medium.

[0020] Figure 5 in Figure 5 A and Figure 5 B are a perspective view of a cooling base of the first modification example and a cross-sectional view showing the flow of a cooling medium.

[0021] Figure 6 in Figure 6 A and Figure 6 B are a perspective view of a reinforcing plate of the second modification example and a cross-sectional view showing the flow of a cooling medium.

[0022] Figure 7 in Figure 7 A and Figure 7 B are a perspective view and a cross-sectional view of a reinforcing plate of the third modification example.

[0023] Figure 8 is a plan view of a reinforcing plate of the fourth modification example.

[0024] Figure 9 in Figure 9 A and Figure 9 B are a plan view of a reinforcing plate of the fifth modification example and a cross-sectional view showing the flow of a cooling medium.

[0025] Figure 10 is a perspective view of a reinforcing plate of the sixth modification example. DETAILED DESCRIPTION

[0026] Hereinafter, the structure of the semiconductor device of the present embodiment will be described with reference to the drawings. Figure 1 is an exploded perspective view of the semiconductor device of the present embodiment. Figure 2 is a plan view of the semiconductor device of the present embodiment and a cooling case possessed by the semiconductor device. Hereinafter, for the convenience of explanation, the semiconductor device of the present embodiment will be referred to as a semiconductor device 1. Figure 1The up-down, left-right, and front-back directions shown are defined as the up-down, left-right, and front-back directions of the semiconductor device and will be explained accordingly. In this embodiment, the long side direction of the semiconductor device (the direction in which the stacked substrates are arranged from the bottom up) is defined as the left-right direction, the short side direction of the semiconductor device is defined as the front-back direction, and the thickness direction of the semiconductor device is defined as the up-down direction. These directions (front-back, left-right, up-down) are terms used for ease of explanation, and their correspondence with each direction may vary depending on the mounting posture of the semiconductor device. For example, the heat dissipation surface side (cooler side) of the semiconductor device is referred to as the lower surface side, and its opposite side is referred to as the upper surface side. In addition, in this specification, top view refers to the view of the upper surface of the semiconductor assembly from above.

[0027] like Figure 1 As shown, the semiconductor device 1 of this embodiment is configured to include a semiconductor component 10 and a cooler 20 for cooling the semiconductor component 10. The semiconductor component 10 has a plurality of circuit element sections 11A, 11B, and 11C disposed on a heat dissipation substrate 21 of the cooler 20 (described later). The semiconductor component 10, for example, uses these circuit element sections 11A, 11B, and 11C to form a three-phase inverter circuit. For example, the circuit element sections 11A, 11B, and 11C respectively form a W-phase circuit, a V-phase circuit, and a U-phase circuit for forming the three-phase inverter circuit.

[0028] The circuit element section 11A constituting the W-phase circuit includes an IGBT element 12, which is a semiconductor element constituting the upper arm, and a freewheeling diode 13 connected in anti-parallel to the IGBT element 12; and an IGBT element 12 constituting the lower arm, and a freewheeling diode 13 connected in anti-parallel to the IGBT element 12. The IGBT element 12 and the freewheeling diode 13 are mounted on an insulating substrate 14 bonded to a heat sink substrate 21. Besides IGBTs (Insulated Gate Bipolar Transistors), the semiconductor element can also be a vertically oriented switching element, such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or an RC (Reverse-Conducting) IGBT. Alternatively, the semiconductor element can be formed using a silicon substrate, a silicon carbide substrate, or a gallium nitride substrate.

[0029] The circuit element portion 11B that constitutes the V-phase circuit and the circuit element portion 11C that constitutes the U-phase circuit also have the same structure as the circuit element portion 11A. The insulating substrate 14 has a first surface and a second surface on the side opposite the first surface. The semiconductor elements described above are mounted on the first surface of the insulating substrate. The second surface of the insulating substrate 14 is joined to the upper surface (joining surface) of the heat dissipation substrate 21. The circuit pattern for constituting the circuit described above is formed in the insulating substrate 14. The insulating substrate 14 is, for example, a DCB substrate, an AMB substrate. It can also be that the insulating substrate 14 has a ceramic board, and the circuit pattern is provided to the ceramic board. The ceramic board can contain alumina, silicon nitride, or aluminum nitride. The insulating substrate 14 can also have a metal plate on the second surface side. The circuit pattern and the metal plate are formed of a metal material of aluminum, copper. The metal material contains an aluminum alloy, a copper alloy. Furthermore, the case where the semiconductor module 10 constitutes a three-phase inverter circuit is described here. However, the semiconductor module 10 of the present application is not limited to the case where it constitutes a three-phase inverter circuit, and can be appropriately changed.

[0030] The cooler 20 is configured to include the heat dissipation substrate 21, a plurality of heat dissipation fins 22 (refer to FIG. 2) provided to the heat dissipation substrate 21, Figure 3 The heat dissipation fins 22 are provided to the surface (heat dissipation surface) of the heat dissipation substrate 21 on the side opposite the surface (joining surface) that is joined to the insulating substrate 14, and will be described in detail later. In addition, the plurality of heat dissipation fins 22 are joined to the reinforcing plate 30 described later at the tips thereof. The heat dissipation substrate 21 is installed to the upper portion of the cooling housing 23. The plurality of heat dissipation fins 22 and the reinforcing plate 30 provided to the lower surface (heat dissipation surface) of the heat dissipation substrate 21 are housed in the recessed portion 24 (first recessed portion) formed in the cooling housing 23. Furthermore, the cooling housing 23 is sometimes referred to as a refrigerant jacket or a water cooling jacket.

[0031] The heat dissipation substrate 21 is configured from a metal plate material having a substantially rectangular shape. For example, the heat dissipation substrate 21 is configured from a metal material of aluminum, copper, iron, or the like. The long side direction of the heat dissipation substrate 21 extends in the left-right direction of the semiconductor device 1, and the short side direction of the heat dissipation substrate 21 extends in the front-rear direction of the semiconductor device 1. The semiconductor module 10 is disposed in the central region of the upper surface of the heat dissipation substrate 21. In the present embodiment, the circuit element portions 11A, 11B, 11C that constitute the semiconductor module 10 are arranged and disposed in the central region of the heat dissipation substrate 21 in the left-right direction. Furthermore, in the present embodiment, the central region of the lower surface side (heat dissipation surface side) of the portion of the heat dissipation substrate 21 in which the circuit element portions 11A, 11B, 11C described above are disposed is sometimes referred to as a heat dissipation region. In addition, a threaded hole 211 is formed penetrating through the vicinity of the corners of the heat dissipation substrate 21. A screw is threaded through the threaded hole 211 as a fastening member (not shown) for fixing the heat dissipation substrate 21 to the cooling housing 23.

[0032] The cooling case 23 has a substantially rectangular parallelepiped shape, and has a rectangular shape in plan view. The cooling case 23 has a shape substantially the same as that of the heat dissipation substrate 21 in plan view. The cooling case 23 has a bottom wall 231 and a side wall 232 provided to a peripheral edge of the bottom wall 231, and has a box shape with an upper opening. In other words, a recess 24 is formed in an upper surface of the cooling case 23. The recess 24 is defined by an upper surface (bottom surface) of the bottom wall 231 and an inner wall surface of the side wall 232. The recess 24 is formed to have a size capable of accommodating the plurality of fins 22 and the reinforcing plate 30, which will be described later in detail.

[0033] The cooling case 23 is provided with an introduction port 233 for introducing a cooling medium into the cooling case 23 and a discharge port 234 for discharging the cooling medium from the cooling case 23. The introduction port 233 is provided in a first side wall 232a extending in the longitudinal direction among the side walls 232. The introduction port 233 is formed to communicate between the outside of the side wall 232 and the recess 24 in the front-rear direction in the left-right direction center of the first side wall 232a. The discharge port 234 is provided in a second side wall 232b extending in the longitudinal direction opposite the first side wall 232a among the side walls 232. The discharge port 234 is formed to penetrate between the outside of the side wall 232 and the recess 24 in the front-rear direction in the left-right direction center of the second side wall 232b. The introduction port 233 and the discharge port 234 are formed, for example, by circular holes. A cylindrical introduction pipe 233a and a discharge pipe 234a are connected to the introduction port 233 and the discharge port 234, respectively. Alternatively, as shown in FIG. B, the semiconductor device 1 can be configured such that the introduction pipe 233a and the discharge pipe 234a are provided to the first and second headers 233b and 234b, respectively. Figure 2 B, the semiconductor device 1 is configured such that the first header 233b is provided on the front side of the plurality of fins 22 and the second header 234b is provided on the rear side of the plurality of fins 22 in the recess 24 of the cooling case 23.

[0034] An O-ring 235 is attached to the upper surface of the side wall 232. The O-ring 235 is disposed in a position of the side wall 232 in which the recess 24 is surrounded. In other words, the O-ring 235 is disposed along a square ring-shaped groove (not shown) formed in the upper surface of the side wall 232. The O-ring 235 functions to prevent liquid leakage from the inside of the cooling case 23 in a case where the heat dissipation substrate 21 is attached to the cooling case 23 and the cooling medium flows in the cooling case 23. In addition, the structure for preventing liquid leakage is not limited to the O-ring 235, and can be a sealing member such as a metal gasket or a liquid seal.

[0035] Threaded holes 236 are formed in the vicinity of the corners of the cooling case 23 (the side wall 232). The threaded holes 236 are arranged in positions corresponding to the threaded holes 211 of the heat dissipation substrate 21 when the heat dissipation substrate 21 is overlapped on the cooling case 23. In a state where the heat dissipation substrate 21 is overlapped on the cooling case 23, the heat dissipation substrate 21 is mounted with respect to the cooling case 23 by inserting screws (not shown) as fastening members into the threaded holes 236 via the threaded holes 211.

[0036] Here, the structure of the heat dissipation substrate 21 and the heat dissipation fins 22 provided on the lower surface of the heat dissipation substrate 21 of the present embodiment will be described with reference to Figure 3 Figure 3 is a diagram illustrating the heat dissipation fins of the semiconductor device of the present embodiment.

[0037] The heat dissipation fins 22 are integrally provided on the lower surface of the heat dissipation substrate 21. The heat dissipation fins 22 can be composed of the same metal material as the heat dissipation substrate 21. The heat dissipation fins 22 are used as a heat dissipation plate, in other words, as a heat sink. For example, as shown in Figure 3 , the heat dissipation fins 22 can use pin heat dissipation fins in which a plurality of prismatic-shaped pins (square pins) are arranged at a prescribed interval with a space therebetween. More specifically, the heat dissipation fins 22 are formed in a rhombus shape in plan view, and the opposite directions of the pair of corners on the diagonal line coincide with the short side direction of the heat dissipation substrate 21 (the flow direction of the refrigerant described later). In addition, the structure of the heat dissipation fins 22 provided on the heat dissipation substrate 21 is not limited to this, and can be appropriately changed. For example, instead of the prismatic shape shown in Figure 3 , a cylindrical pin can be provided, or a structure in which a plurality of heat dissipation fins in a blade shape extending in the front-rear direction are arranged parallel to each other can be provided. The heat dissipation fins 22 can be provided on the heat dissipation substrate 21 by brazing, planting, cutting processing, or plastic processing.

[0038] In addition, the shape and size of the heat dissipation fins 22 are preferably appropriately set in consideration of the conditions for introduction of the cooling medium into the cooler 20 (i.e., the pump performance and the like), the kind and properties of the cooling medium (particularly, viscosity and the like), the target heat removal amount, and the like. In addition, the heat dissipation fins 22 are formed to have a height such that, in the case of being accommodated in the cooling case 23 (more specifically, the recessed portion 24 of the cooling case 23), a certain gap is present between the top end of the heat dissipation fins 22 and the bottom wall 231 of the cooling case 23 (see Figure 4 ).

[0039] ​The area in the heat sink 22 disposed on the heat sink substrate 21 preferably includes the area on the side (back side) of the insulating substrate 14 opposite to the mounting area of ​​the semiconductor element (IGBT element 12, freewheeling diode 13) when the insulating substrate 14 is bonded to the heat sink substrate 21. In other words, the area in which the heat sink 22 is integrally disposed on the heat sink substrate 21 preferably includes the area directly below the IGBT element 12 and the freewheeling diode 13 (the aforementioned heat dissipation area).

[0040] In this embodiment, a heat sink assembly 22a, consisting of multiple prism-shaped heat sinks 22 arranged together, is provided on the lower surface (heat dissipation surface) of the heat dissipation substrate 21. The heat sink assembly 22a has a generally cuboid shape. More preferably, the heat sink assembly 22a is cuboid, but it is not limited to this; it can also be chamfered or deformed. The long side of the heat sink assembly 22a is aligned with the long side of the cooling housing 23 (recess 24).

[0041] However, for semiconductor devices with so-called open heat sinks, a certain degree of rigidity is required to suppress thermal deformation. The rigidity of the heat sink is ensured by the heat dissipation substrate on which it is mounted; to achieve greater strength, the thickness of the heat dissipation substrate itself is considered to be increased. However, increasing the thickness of the heat dissipation substrate increases thermal resistance, which in turn affects the original cooling performance. In other words, it can be said that ensuring the rigidity of the heat dissipation substrate and ensuring cooling performance are inversely related.

[0042] Therefore, the inventors of this application conceived of the present invention in order to ensure both the rigidity of the heat dissipation substrate and the cooling performance. Specifically, in this embodiment, a reinforcing plate 30 is arranged on the heat dissipation surface side of the heat dissipation substrate 21 to cover a plurality of heat sinks 22, and the reinforcing plate 30 is joined to the top of the plurality of heat sinks 22.

[0043] Here, refer to Figure 3 and Figure 4 This section describes the detailed structure of the semiconductor device equipped with a cooler according to this embodiment. Figure 4 This is a perspective view of the cooling base in this embodiment. Figure 4 A) and a cross-sectional view showing the flow of the cooling medium ( Figure 4 B).

[0044] like Figure 3 and Figure 4As shown, the reinforcing plate 30 is composed of a metal plate material having a substantially rectangular shape. For example, the reinforcing plate 30 is composed of a metal material such as aluminum, copper, iron, or the like. The metal material can be an alloy having aluminum, copper, iron, or the like as a main component. Further, the reinforcing plate 30 can be composed of the same metal material as the heat dissipation substrate 21 (the heat dissipation fins 22).

[0045] The reinforcing plate 30 has a rectangular shape corresponding to the heat dissipation region of the heat dissipation substrate 21 so as to cover the entire plurality of heat dissipation fins 22 (the lower surface of the assembly 22a of the heat dissipation fins 22). In addition, the thickness of the reinforcing plate 30 is set to be smaller than the thickness of the heat dissipation substrate 21. Further, the top ends of the plurality of heat dissipation fins 22 are joined to one face of the reinforcing plate 30. The plurality of heat dissipation fins 22 and the reinforcing plate 30 are joined, for example, by brazing. Thus, the heat dissipation substrate 21 in which the plurality of heat dissipation fins 22 and the reinforcing plate 30 are integrated is obtained. Alternatively, the reinforcing plate 30 can have a rectangular shape in plan view having long sides and short sides, can be arranged so as to oppose the top ends of the plurality of heat dissipation fins 22, and can be joined to the top ends of the plurality of heat dissipation fins 22.

[0046] The cooling case 23 is mounted to the heat dissipation substrate 21 in which the plurality of heat dissipation fins 22 and the reinforcing plate 30 are integrated. The cooling case 23 has a recess 24 corresponding to the heat dissipation region, and is mounted so as to house the plurality of heat dissipation fins 22 and the reinforcing plate 30 within the recess 24. Specifically, the side surface of the assembly 22a of the heat dissipation fins 22 is surrounded by the quadrangular ring-shaped side wall 232, and the lower surface of the reinforcing plate 30 opposes the bottom surface (bottom wall 231) of the recess 24 with a prescribed gap D1 (refer to FIG. 2B) therebetween. Figure 4 B).

[0047] In the semiconductor device 1 of the present embodiment, the three circuit element portions 11A, 11B, 11C are arranged in the long side direction (left-right direction) of the heat dissipation substrate 21. In addition, the plurality of heat dissipation fins 22 are provided in the heat dissipation region of the heat dissipation substrate 21 corresponding to the heat dissipation surface of the portion in which the circuit element portions 11A, 11B, 11C are provided. In addition, the cooling case 23 has the side wall 232 that surrounds the plurality of heat dissipation fins 22. The side wall 232 has a first side wall 232a and a second side wall 232b that oppose each other in the front-rear direction (short side direction) that intersects the prescribed direction (long side direction) in which the three circuit element portions 11A, 11B, 11C are arranged. The first side wall 232a and the second side wall 232b oppose each other with the assembly 22a of the heat dissipation fins 22 therebetween in the front-rear direction. As described above, the inlet port 233 for the refrigerant is provided in the first side wall 232a, and the outlet port 234 for the refrigerant is provided in the second side wall 232b. The refrigerant flows in the short side direction between the plurality of heat dissipation fins 22 from the inlet port 233 to the outlet port 234 (refer to FIG. 2B and FIG. 3B). Figure 2 B and Figure 4 B).

[0048] More specifically, when refrigerant is introduced into the recess 24 from the inlet 233, the refrigerant collides with the side of the upstream side of the assembly 22a of heat sinks 22 and diffuses in the left-right direction (long side direction of the assembly 22a), while flowing in the short side direction inside the assembly 22a through the gaps between the multiple heat sinks 22 (see reference). Figure 2 B). The refrigerant is discharged from the downstream side of the assembly 22a to the outside of the cooling housing 23 through the outlet 234.

[0049] In this embodiment, since a reinforcing plate 30 is attached to the top of the plurality of heat sinks 22, the overall rigidity of the heat sink substrate 21, which includes the plurality of heat sinks 22 and the reinforcing plate 30, is improved. This suppresses warping of the heat sink substrate 21 in the thickness direction (vertical direction) when the semiconductor component 10 is mounted on the heat sink substrate 21 and heated. Therefore, the depth of the recess 24 can be reduced, and the lower surface of the reinforcing plate 30 can be brought closer to the bottom surface of the recess 24, further reducing the gap D1 between the reinforcing plate 30 and the bottom surface of the recess 24.

[0050] Furthermore, by using the reinforcing plate 30 to close the open space at the top of the heat sink 22, a closed refrigerant flow path is formed between the multiple heat sinks 22. In this case, the gap D2 between the multiple heat sinks 22 is preferably larger than the gap D1 between the reinforcing plate 30 and the bottom surface of the recess 24.

[0051] Based on these structures, the reinforcing plate 30 prevents refrigerant from flowing into the gap D1 between the reinforcing plate 30 and the bottom surface of the recess 24, while guiding more refrigerant between the multiple heat sinks 22. This promotes heat exchange between the refrigerant and the heat sinks 22, improving the cooling efficiency of the cooler 20. In other words, it ensures both the rigidity of the cooler 20 and its cooling performance. Furthermore, by increasing rigidity using the reinforcing plate 30, the thickness of the heat sink substrate 21 itself can be reduced, improving its thermal conductivity. The thickness t of the reinforcing plate 30 can be the same as or less than the thickness T of the heat sink substrate 21 (see reference). Figure 4 B). The height h of the heat sink 22 can be selected appropriately.

[0052] Next, refer to Figures 5 to 10 Explain the variations. Figure 5 This is a perspective view of the cooling base of the first modified example. Figure 5 A) and a cross-sectional view showing the flow of the cooling medium ( Figure 5 B). Figure 6 This is a perspective view of the reinforcing plate in the second modified example. Figure 6 A) and a cross-sectional view showing the flow of the cooling medium ( Figure 6 B). Figure 7 This is a perspective view of the reinforcing plate in the third variation. Figure 7A) and a sectional view Figure 7 B). Figure 8 is a plan view of a reinforcing plate of a 4th modification. Figure 9 is a plan view of a reinforcing plate of a 5th modification Figure 9 A) and a sectional view showing the flow of a cooling medium Figure 9 B). Figure 10 is a perspective view of a reinforcing plate of a 6th modification. Further, in the modifications shown below, structures common to the present embodiment are denoted by the same reference numerals as possible, and the explanation is appropriately omitted.

[0053] As shown in Figure 5 , the heat dissipation substrate 21 of the 1st modification has a recessed portion 21a (2nd recessed portion) recessed in the thickness direction in correspondence with the region where the plurality of heat dissipation fins 22 are provided. More specifically, the recessed portion 21a is recessed toward the surface side in the heat dissipation region on the back surface side of the heat dissipation substrate 21 where the circuit element portions 11A, 11B, 11C are arranged. Due to the recessed portion 21a, the plate thickness of the heat dissipation region of the heat dissipation substrate 21 is thinned. The plurality of heat dissipation fins 22 protrude downward from the bottom surface of the recessed portion 21a. The reinforcing plate 30 is joined to the top ends of the plurality of heat dissipation fins 22 in a manner to cover the entire lower surface of the aggregate 22a.

[0054] According to the 1st modification, by joining the reinforcing plate 30 to the heat dissipation fins 22, the rigidity of the entire heat dissipation substrate 21 including the heat dissipation fins 22 and the reinforcing plate 30 is improved. Therefore, even if the recessed portion 21a is formed in a part of the heat dissipation substrate 21, the rigidity of the entire heat dissipation substrate 21 can be ensured. Since the recessed portion 21a is formed in the heat dissipation region, the plate thickness of the heat dissipation substrate 21 directly below the circuit element portions 11A, 11B, 11C is thinned, and the thermal resistance can be reduced. As a result, the heat conduction of the heat generated by the circuit element portions 11A, 11B, 11C can be improved, and the heat dissipation effect can be improved.

[0055] In addition, as shown in Figure 5 B, since the recessed portion 21a is formed in correspondence with the region where the plurality of heat dissipation fins 22 are provided, when the refrigerant flows into between the plurality of heat dissipation fins 22, a flow along the surface of the recessed portion 21a is generated. Thereby, within the heat dissipation fins 22, the flow of the refrigerant is disturbed in the height direction (upward and downward direction) of the heat dissipation fins 22. Due to the generation of such a disturbed flow of the refrigerant, the number of collisions between the refrigerant and the surface of the heat dissipation fins 22 increases, and the heat exchange between the refrigerant and the heat dissipation fins 22 is promoted. Thus, the cooling efficiency can be further improved.

[0056] In addition, in Figure 5In the embodiment, the case where the recesses 21a of a top view rectangular shape are formed with the same depth over the entire heat dissipation region is described, but the structure is not limited to this. The recesses 21a can also be formed in a local division manner according to a site where it is desired to improve the cooling efficiency, and can also be formed so that the depth of the recesses 21a also changes in stages.

[0057] As shown in Figure 6 The reinforcing plate 40 of the second modified example is formed with a bent portion (first bent portion 41 and second bent portion 42) for guiding the flow of refrigerant on the pair of edge portions opposite in the short side direction. Specifically, the first bent portion 41 bent toward the direction away from the top end of the heat dissipation fin 22 (downward) and the second bent portion 42 bent toward the base end side of the heat dissipation fin 22 (upward) are provided on the edge portion of the reinforcing plate 40 in the short side direction.

[0058] As shown in Figure 6 A and Figure 6 B, the first bent portion 41 and the second bent portion 42 are alternately formed in the long side direction arrangement on the edge portion of one side (upstream side in the flow direction of refrigerant) in the short side direction of the reinforcing plate 40. In Figure 6 A, a pair of first bent portions 41 are arranged on both end sides, and a second bent portion 42 is arranged between the pair of first bent portions 41. In contrast, the first bent portion 41 is formed over the entire length on the edge portion of the other side (downstream side in the flow direction of refrigerant) in the short side direction of the reinforcing plate 40. The first bent portion 41 and the second bent portion 42 can be divided and provided in correspondence with the circuit element portions 11A, 11B, 11C (not shown in Figure 6 B) arranged on the heat dissipation substrate 21.

[0059] According to the first bent portion 41 bent downward (toward the bottom surface of the recess 24), the gap D1 between the reinforcing plate 40 and the bottom surface of the recess 24 is blocked. Thereby, the refrigerant is less likely to flow to the gap D1 and is more likely to flow to the gap D2 between the plurality of heat dissipation fins 22. In addition, according to the second bent portion 42 bent upward (toward the side opposite to the bottom surface of the recess 24), the refrigerant can be guided from above the recess 24 to the gap D2 between the plurality of heat dissipation fins 22. In this way, the bent portion can be used to adjust the refrigerant flow path and improve the cooling efficiency. In addition, by adjusting the shape of the bent portion in the upward or downward manner in correspondence with the arrangement site of each circuit element portion as a heat generating component, it is possible to control the flow rate distribution of the refrigerant for each circuit element portion and perform uniform temperature management. In addition, the bending angle of the bent portion is not limited to a right angle, and can be, for example, an angle inclined outward.

[0060] As shown in Figure 7As shown, the reinforcing plate 50 of the third modification has multiple beam portions 51 formed on the side opposite to the surface where the multiple heat sinks 22 are joined. Specifically, the beam portions 51 are provided on the surface of the reinforcing plate 50 opposite to the bottom surface of the recess 24. The beam portions 51 protrude downward from the surface of the reinforcing plate 50 (the bottom surface of the recess 24) and extend along the long side direction (left-right direction) of the reinforcing plate 50. In addition, the beam portions 51 have multiple ( Figure 7 (There are four in the middle). The beam portion 51 is formed, for example, by pressing a protrusion from the upper surface side (the joint surface side relative to the heat sink 22) toward the lower surface side of the reinforcing plate 50. In addition, the shape, number, length, etc. of the beam portions 51 can be appropriately changed. According to the beam portion 51, the rigidity of the reinforcing plate 50 is improved, and the warping of the reinforcing plate 50 can be suppressed.

[0061] like Figure 8 As shown, in the fourth variation, the reinforcing plate 60 has a positioning portion 61 on the surface (joining surface) where it engages with the plurality of heat sinks 22, allowing at least a portion of the heat sinks 22 to be engaged. Specifically, the positioning portions 61 are respectively provided at the four corners of the rectangular reinforcing plate 60. The positioning portions 61 are formed, for example, by dome-shaped protrusions, and are preferably formed to a size corresponding to the gap between adjacent heat sinks 22. According to this structure, it is easy to position the reinforcing plate 60 relative to the plurality of heat sinks 22, thereby reducing assembly time.

[0062] like Figure 9 As shown, the reinforcing plate 70 of the fifth modification has a plurality of protrusions 71 on the surface (joining surface) where the plurality of heat sinks 22 are joined. The plurality of protrusions 71 are positioned so as not to overlap with the plurality of heat sinks 22 when viewed from above. For example, the plurality of protrusions 71 are arranged at the same spacing as the plurality of heat sinks 22. The protrusions 71 are formed, for example, in a dome-shaped convex shape, and are preferably formed to be slightly smaller than the gap between adjacent heat sinks 22. According to this structure, since numerous protrusions 71 are provided in the refrigerant flow path formed between the plurality of heat sinks 22, the refrigerant flow is turbulent in the height direction (vertical direction) of the heat sink 22 when the refrigerant flows past the vicinity of the protrusions 71 within the heat sink 22. Due to this turbulence of the refrigerant, the number of collisions between the refrigerant and the surface of the heat sink 22 increases, thereby promoting heat exchange between the refrigerant and the heat sink 22. Therefore, cooling efficiency can be further improved.

[0063] In the above embodiments, the case where the reinforcing plate is formed into a rectangular shape in top view has been described, but it is not limited to this. For example, it could also be... Figure 10 The structure shown. (As illustrated) Figure 10As shown, the reinforcing plate 80 of the sixth modification example is formed with a trapezoidal notch portion 81 in which the width of the central portion in the longitudinal direction is narrower than the width of the both end portions. That is, a state in which only the tip end of the fin 22 is exposed in the portion of the notch portion 81 is obtained. In addition, a plurality of beam portions 82 extending in the longitudinal direction are formed in the lower surface (the surface on the side opposite to the joint surface) of the reinforcing plate 80. The beam portions 82 protrude toward the side opposite to the fin 22. In this way, the rigidity of the reinforcing plate 80 as a whole is ensured by the beam portions 82 in correspondence with the amount of decrease in the rigidity of the reinforcing plate 80 itself due to the notch portion 81. In addition, due to the notch portion 81, the tip end of a portion of the fin 22 on the central side in the longitudinal direction is open, and thus the flow rate distribution of the refrigerant can be adjusted on the both end sides and the central side in the longitudinal direction of the reinforcing plate 80. In this way, by changing the shape of the reinforcing plate 80 with respect to the assembly 22a of the fins 22, the cooling performance can be appropriately controlled. The reinforcing plate 80 has a portion (portion A) in which the width is wide and the area is large, and a portion (portion B) in which the width is narrow and the area is small. By arranging the reinforcing plate 80 such that the portion A faces the portion of the heat dissipation substrate 21 that is likely to deform to a relatively large degree, and the portion B faces the portion of the heat dissipation substrate 21 that is likely to deform to a relatively small degree, the balance of the deformation of the heat dissipation substrate 21 as a whole can be obtained.

[0064] In addition, the present embodiment and the modifications are explained, but as other embodiments, the above-described embodiment and modifications can be combined as a whole or partially. For example, the features of each of the modifications of Figures 5 to 10 may be combined. Specifically, the recessed portion 21a of Figure 5 and the bent portion of Figure 6 may be combined, the positioning portion 61 of Figure 8 and the protrusion portion 71 of Figure 9 may be combined.

[0065] As an example of the combination, the heat dissipation substrate 21, the plurality of insulating substrates 14, the plurality of semiconductor elements 12, the plurality of fins 22, and the reinforcing plate 30 can be provided as a component.

[0066] In the assembly, the heat dissipation substrate 21 may have a bonding surface and a heat dissipation surface opposite to the bonding surface, and may be rectangular in plan view. Alternatively, multiple insulating substrates 14 may each have a first surface and a second surface opposite to the first surface, and be arranged along the long side of the heat dissipation substrate 21. Each of the multiple insulating substrates 14 can bond its second surface to the bonding surface of the heat dissipation substrate 21. Semiconductor elements 12 may be mounted on the first surfaces of the multiple insulating substrates 14. Multiple heat sinks 22 are disposed below the multiple insulating substrates 14, on the heat dissipation surface of the heat dissipation substrate 21. Alternatively, a reinforcing plate 30 may be arranged opposite the top ends of at least a portion of the heat sinks 22, and bonded to the top ends of the multiple heat sinks 22. Here, the thickness of the reinforcing plate 30 may be the same as the thickness of the heat dissipation substrate 21, or it may be greater than or less than the thickness of the heat dissipation substrate 21.

[0067] Alternatively, the reinforcing plate 30 can be rectangular in top view and arranged opposite the tops of all the plurality of heat sinks 22, and joined to the tops of the plurality of heat sinks 22. The heat dissipation substrate 21 and the reinforcing plate 30 can each be plates containing aluminum or aluminum alloy. The insulating substrate 14 can each have a ceramic plate containing alumina, silicon nitride, or aluminum nitride.

[0068] In the above-described components, the heat dissipation substrate 21 may be in the shape of protruding from the reinforcing plate 30 toward the insulating substrate 14 or may be flat.

[0069] The component is suitable for a cooling housing 23 having a recess 24 capable of accommodating multiple heat sinks 22 and reinforcing plates 30 (see reference). Figure 2 The component can be used by fixing it to the side wall 232 of the cooling housing 23 via a sealing member. Here, the length of the plurality of heat sinks 22 and the thickness of the reinforcing plate 30 can be selected such that the gap between the plurality of heat sinks 22 is greater than the gap between the reinforcing plate 30 and the bottom surface of the recess 24. Furthermore, the component and the cooling housing 23 can be configured such that one side of the plurality of heat sinks 22 is provided in the recess 24 (…). Figure 2 The first manifold 233b (in front of B) and the other side opposite to one side of the plurality of heat sinks 22 ( Figure 2 The second manifold 234b (at the rear of B) can be a manifold where the refrigerant introduced from the inlet 233 expands along the long side in the first manifold 233b, flows in front of the multiple heat sinks 22, and is discharged from the rear. After being converged in the second manifold 234b, it is discharged from the outlet 234.

[0070] Moreover, the present application is not limited to the above-described embodiments, but can be variously modified to be implemented. In the above-described embodiments, the size, shape, function, and the like of the structural elements shown in the drawings are not limited thereto, but can be appropriately modified within a range where the effects of the present application are exerted. Furthermore, appropriate modifications can be made within a range not deviating from the object of the present application to be implemented.

[0071] The features in the above-described embodiments are summarized below.

[0072] The semiconductor device of the above-described embodiment includes an insulating substrate having a first surface and a second surface on the side opposite to the first surface, a semiconductor element mounted on the first surface of the insulating substrate, and a cooler for cooling the semiconductor element, in which the cooler includes a heat dissipation substrate having a bonding surface and a heat dissipation surface on the side opposite to the bonding surface, the bonding surface being bonded to the second surface of the insulating substrate, a plurality of heat dissipation fins provided on the heat dissipation surface of the heat dissipation substrate, a reinforcing plate disposed so as to cover the plurality of heat dissipation fins, the reinforcing plate being bonded to the top ends of the plurality of heat dissipation fins, and a cooling housing having a recess portion that accommodates the plurality of heat dissipation fins and the reinforcing plate, the gap between the plurality of heat dissipation fins being larger than the gap between the reinforcing plate and the bottom surface of the first recess portion.

[0073] In the semiconductor device of the above-described embodiment, the insulating substrate on which the semiconductor element is mounted is provided in plurality in alignment in a prescribed direction, the plurality of heat dissipation fins are provided on the heat dissipation region of the heat dissipation surface of the heat dissipation substrate corresponding to the portion on which the plurality of insulating substrates are provided, the cooling housing has a side wall that surrounds the plurality of heat dissipation fins, the side wall has a first side wall and a second side wall that are opposed in a direction intersecting the prescribed direction in which the plurality of insulating substrates are aligned, a refrigerant inlet is provided on the first side wall, and a refrigerant outlet is provided on the second side wall, the refrigerant flows between the plurality of heat dissipation fins in a direction intersecting the prescribed direction from the refrigerant inlet toward the refrigerant outlet.

[0074] In the semiconductor device of the above-described embodiment, the reinforcing plate has a second recess portion on the heat dissipation surface corresponding to the region on which the plurality of heat dissipation fins are provided, the second recess portion being recessed in the thickness direction.

[0075] In the semiconductor device of the above-described embodiment, the reinforcing plate has a first bent portion on the edge portion on the upstream side and / or the downstream side of the flow direction of the refrigerant, the first bent portion being bent toward the bottom surface of the first recess portion.

[0076] In the semiconductor device of the above embodiment, the heat dissipation substrate has a second bent portion at an edge portion on the upstream side and / or the downstream side in the flow direction of the refrigerant, the second bent portion being bent toward the side opposite to the bottom surface of the first recessed portion.

[0077] In the semiconductor device of the above embodiment, the reinforcing plate has a beam portion formed on the side opposite to the surface at which the plurality of heat dissipation fins are joined.

[0078] In the semiconductor device of the above embodiment, the reinforcing plate has a positioning portion on the surface at which the plurality of heat dissipation fins are joined, at least a part of the plurality of heat dissipation fins being capable of being engaged with the positioning portion.

[0079] In the semiconductor device of the above embodiment, the reinforcing plate has a plurality of protruding portions on the surface at which the plurality of heat dissipation fins are joined, the plurality of protruding portions being provided at positions that do not overlap the plurality of heat dissipation fins when viewed from above.

[0080] Industrial applicability

[0081] The semiconductor device of the present application has an effect of being able to ensure rigidity and being able to ensure cooling performance, and is suitable for a semiconductor device such as a motor drive control inverter for a vehicle, which requires miniaturization and high output.

[0082] This application is based on Japanese Patent Application No. 2019-229215 filed on December 19, 2019. The entire contents of the application are hereby incorporated by reference.

Claims

1. A semiconductor device, the semiconductor device comprising: An insulating substrate having a first surface and a second surface opposite to the first surface; A semiconductor element mounted on the first surface of the insulating substrate; as well as A cooler for cooling the semiconductor element. The cooler includes: A heat dissipation substrate having a bonding surface and a heat dissipation surface on the side opposite to the bonding surface, the bonding surface being bonded to the second surface of the insulating substrate; Multiple heat sinks are disposed on the heat dissipation surface of the heat dissipation substrate; A reinforcing plate, configured to cover the plurality of heat sinks, and engaged with the top ends of the plurality of heat sinks; and Cooling housing having a first recess for accommodating the plurality of heat sinks and the reinforcing plate, The gap between the plurality of heat sinks is greater than the gap between the reinforcing plate and the bottom surface of the first recess, wherein... Multiple insulating substrates carrying the semiconductor elements are arranged in a predetermined direction. The plurality of heat sinks are disposed in the heat dissipation area corresponding to the heat dissipation surface of the heat dissipation substrate that is provided with the plurality of insulating substrates. The cooling housing has sidewalls surrounding the plurality of heat sinks. The sidewall has a first sidewall and a second sidewall, which are opposite each other in a direction intersecting the predetermined direction in which the plurality of insulating substrates are arranged. A refrigerant inlet is provided on the first side wall, and a refrigerant outlet is provided on the second side wall. The refrigerant flows from the inlet toward the outlet between the plurality of heat sinks in a direction intersecting the predetermined direction. The reinforcing plate has a first bend at its edge on the upstream and / or downstream side in the direction of refrigerant flow, the first bend being bent toward the bottom surface of the first recess.

2. The semiconductor device according to claim 1, wherein, The heat dissipation substrate has a second recess on the heat dissipation surface that corresponds to the area where the plurality of heat sinks are provided and is recessed along the thickness direction.

3. A semiconductor device, the semiconductor device comprising: An insulating substrate having a first surface and a second surface opposite to the first surface; A semiconductor element mounted on the first surface of the insulating substrate; as well as A cooler for cooling the semiconductor element. The cooler includes: A heat dissipation substrate having a bonding surface and a heat dissipation surface on the side opposite to the bonding surface, the bonding surface being bonded to the second surface of the insulating substrate; Multiple heat sinks are disposed on the heat dissipation surface of the heat dissipation substrate; A reinforcing plate, configured to cover the plurality of heat sinks, and engaged with the top ends of the plurality of heat sinks; and Cooling housing having a first recess for accommodating the plurality of heat sinks and the reinforcing plate, The gap between the plurality of heat sinks is greater than the gap between the reinforcing plate and the bottom surface of the first recess, wherein... Multiple insulating substrates carrying the semiconductor elements are arranged in a predetermined direction. The plurality of heat sinks are disposed in the heat dissipation area corresponding to the heat dissipation surface of the heat dissipation substrate that is provided with the plurality of insulating substrates. The cooling housing has sidewalls surrounding the plurality of heat sinks. The sidewall has a first sidewall and a second sidewall, which are opposite each other in a direction intersecting the predetermined direction in which the plurality of insulating substrates are arranged. A refrigerant inlet is provided on the first side wall, and a refrigerant outlet is provided on the second side wall. The refrigerant flows from the inlet toward the outlet between the plurality of heat sinks in a direction intersecting the predetermined direction. The reinforcing plate has a second bend at its edge on the upstream and / or downstream side in the direction of refrigerant flow, the second bend being bent toward the side opposite to the bottom surface of the first recess.

4. The semiconductor device according to claim 3, wherein, The heat dissipation substrate has a second recess on the heat dissipation surface that corresponds to the area where the plurality of heat sinks are provided and is recessed along the thickness direction.

5. A semiconductor device comprising: An insulating substrate having a first surface and a second surface opposite to the first surface; A semiconductor element mounted on the first surface of the insulating substrate; as well as A cooler for cooling the semiconductor element. The cooler includes: A heat dissipation substrate having a bonding surface and a heat dissipation surface on the side opposite to the bonding surface, the bonding surface being bonded to the second surface of the insulating substrate; Multiple heat sinks are disposed on the heat dissipation surface of the heat dissipation substrate; A reinforcing plate, configured to cover the plurality of heat sinks, and engaged with the top ends of the plurality of heat sinks; and Cooling housing having a first recess for accommodating the plurality of heat sinks and the reinforcing plate, The gap between the plurality of heat sinks is greater than the gap between the reinforcing plate and the bottom surface of the first recess, wherein... The reinforcing plate has a beam portion formed on a side opposite to the side where the plurality of heat sinks are joined.

6. The semiconductor device according to claim 5, wherein, The heat dissipation substrate has a second recess on the heat dissipation surface that corresponds to the area where the plurality of heat sinks are provided and is recessed along the thickness direction.

7. A semiconductor device comprising: An insulating substrate having a first surface and a second surface opposite to the first surface; A semiconductor element mounted on the first surface of the insulating substrate; as well as A cooler for cooling the semiconductor element. The cooler includes: A heat dissipation substrate having a bonding surface and a heat dissipation surface on the side opposite to the bonding surface, the bonding surface being bonded to the second surface of the insulating substrate; Multiple heat sinks are disposed on the heat dissipation surface of the heat dissipation substrate; A reinforcing plate, configured to cover the plurality of heat sinks, and engaged with the top ends of the plurality of heat sinks; and Cooling housing having a first recess for accommodating the plurality of heat sinks and the reinforcing plate, The gap between the plurality of heat sinks is greater than the gap between the reinforcing plate and the bottom surface of the first recess, wherein... The reinforcing plate has a positioning portion on the surface where it engages with the plurality of heat sinks, and at least a portion of the plurality of heat sinks can be engaged with the positioning portion.

8. The semiconductor device according to claim 7, wherein, The heat dissipation substrate has a second recess on the heat dissipation surface that corresponds to the area where the plurality of heat sinks are provided and is recessed along the thickness direction.

9. A semiconductor device comprising: An insulating substrate having a first surface and a second surface opposite to the first surface; A semiconductor element mounted on the first surface of the insulating substrate; as well as A cooler for cooling the semiconductor element. The cooler includes: A heat dissipation substrate having a bonding surface and a heat dissipation surface on the side opposite to the bonding surface, the bonding surface being bonded to the second surface of the insulating substrate; Multiple heat sinks are disposed on the heat dissipation surface of the heat dissipation substrate; A reinforcing plate, configured to cover the plurality of heat sinks, and engaged with the top ends of the plurality of heat sinks; and Cooling housing having a first recess for accommodating the plurality of heat sinks and the reinforcing plate, The gap between the plurality of heat sinks is greater than the gap between the reinforcing plate and the bottom surface of the first recess, wherein... The reinforcing plate has multiple protrusions on the surface where it joins the plurality of heat sinks. The plurality of protrusions are located in positions that do not overlap with the plurality of heat sinks when viewed from above.

10. The semiconductor device according to claim 9, wherein, The heat dissipation substrate has a second recess on the heat dissipation surface that corresponds to the area where the plurality of heat sinks are provided and is recessed along the thickness direction.

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