Semiconductor device

Abstract

To provide a semiconductor device that achieves both productivity and heat dissipation.SOLUTION: A semiconductor device includes a plurality of power modules having semiconductor elements, a plurality of heat dissipating bases disposed on the heat dissipating surface side of the plurality of power modules via a heat dissipating member and having heat dissipating fins, a frame having a plurality of openings, and a cover that forms a coolant channel by covering the heat dissipating base and the frame, and the plurality of heat dissipating bases closes the plurality of openings respectively, and the cover has an elastic biasing portion on a surface in contact with the heat dissipating fins to bias the heat dissipating base by pressing toward the power module.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a semiconductor device.

Background Art

[0002] As the background art of the present invention, Patent Document 1 below discloses a configuration in which fin 2 deforms following the side surface of the module from the relative displacement between fin 1 and fin 2, reducing the gap between fin 2 and the module.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional fin-integrated water channel using brazing·FSW (Friction Stir Welding), since the clearance of the fins can be eliminated, the heat transfer rate is high. However, there is no function to follow the variation in the thickness of a plurality of circuit body packages, each of which is a circuit body, and the TIM (Thermal Interface Material) of the heat conductive material becomes thick, resulting in a problem that the cooling performance of the package deteriorates. Further, in order to prevent the deterioration of the cooling performance due to the variation in the thickness of the circuit body package, strict dimensional accuracy is required at the joint between the fin and the component covering it, which causes a problem of high cost.

[0005] Based on this, an object of the present invention is to provide a semiconductor device having a water channel structure that can improve productivity by reducing the cost of components and eliminating the variation in the thickness of the package, and maintain high heat dissipation performance.

Means for Solving the Problems

[0006] The semiconductor device of the present invention includes a plurality of power modules having semiconductor elements, a plurality of heat dissipation bases disposed via a heat dissipation member on the heat dissipation surface side of the plurality of power modules and having heat dissipation fins, a frame having a plurality of openings, and a cover that forms a refrigerant flow path by covering the heat dissipation bases and the frame. The plurality of heat dissipation bases each block the plurality of openings, and the cover has an elastic biasing portion on the surface that contacts the heat dissipation fins, and biases the heat dissipation bases by pressing them toward the power modules.

Advantages of the Invention

[0007] A semiconductor device that can achieve both productivity and heat dissipation can be provided.

Brief Description of the Drawings

[0008]

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[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and for the sake of clarity of explanation, omissions and simplifications are made as appropriate. The present invention can be implemented in various other forms. Unless otherwise particularly limited, each component may be in a single or plural number.

[0010] In the drawings, the positions, sizes, shapes, ranges, etc. of the respective components shown may not represent the actual positions, sizes, shapes, ranges, etc. in order to facilitate the understanding of the invention. For this reason, the present invention is not necessarily limited to the positions, sizes, shapes, ranges, etc. disclosed in the drawings.

[0011] (FIG. 1) The semiconductor device 100 has a structure around a water channel that cools a power module including semiconductor elements from both sides, and this water channel is formed by a cover 2 provided with an elastic biasing portion 1. The connection member 15 and the structure of the water channel will be described later.

[0012] (FIG. 2) A part of the cover 2 serves as the elastic biasing portion 1, and each elastic biasing portion 1 is provided at a position corresponding to each power module 3. Heat dissipation fins 9 are arranged corresponding to each elastic biasing portion 1, and by pressurizing the cover 2 during the manufacturing process, the elastic biasing portion 1 is in close contact with the heat dissipation fins 9. A heat dissipation base 12 is arranged at a position facing the elastic biasing portion 1 with the heat dissipation fins 9 in between.

[0013] A flow path 22 is formed by the elastic biasing portion 1, the heat dissipation fins 9, and the heat dissipation base 12. The refrigerant flowing in from the flow path inlet / outlet 11 flows in the flow path 22. In the case of the power module 3 cooled from both sides, the refrigerant is also made to flow into the flow path 22a on the opposite side through the piping component 10.

[0014] The heat dissipation base 12 is mounted in the through-hole 8a provided in the frame 8, and the gap between the heat dissipation base 12 and the frame 8 is filled and sealed with a joining member 7 (sealing member), thereby improving the adhesion. Further, the heat dissipation base 12 is insulated from the power module 3 and is in contact with the power module 3 via an insulating member 6 and a heat dissipation member 5 (TIM) on the heat dissipation surface side of the power module 3 in order to dissipate heat. The heat dissipation member 5 is made of a material such as resin or grease. One heat dissipation base 12 corresponds to one power module 3. The sealing member 7 is an adhesive, a rubber elastic material, a brazing material, etc., and is a material that can be deformed in the direction from the heat dissipation base 12 to the power module 3 when pressure is applied to the cover 2 in the manufacturing process.

[0015] The heat dissipation fins 9 can have a structure in which the semiconductor device 100 corresponds to all three-phase power modules 3 with the heat dissipation fins 9 provided on one heat dissipation base 12. However, if such a structure is adopted, there is a high possibility of distortion due to pressure during the manufacturing process. Further, a clearance may occur between the cover 2 and the heat dissipation fins 9, which may cause the refrigerant in the flow path 22 to leak. Therefore, by dividing the heat dissipation base 12 into six and configuring the heat dissipation fins 9 to correspond to individual power modules 3, the overall distortion is reduced. Also, by dividing the heat dissipation fins 9 into six, heat dissipation fins 9 with high precision and easy to process can be produced, thus improving the productivity of the semiconductor device 100.

[0016] The semiconductor device 100 has a structure in which the openings of the power module 3 are closed by a plurality of heat dissipation fins 9 and heat dissipation bases 12. This opening is formed by the frame 8 and is a through-hole 8a provided for each power module 3. Thereby, the bonding reliability is improved.

[0017] By doing so, while reducing the clearance (gap) that occurs at the tip portion of the heat dissipation fin 9 due to the distortion of the heat dissipation fin 9 that has occurred conventionally by the elastic deformation of the elastic biasing portion 1 provided in the water channel cover 2, the adhesion between the heat dissipation fin 9 and the power module 3 is improved. The elastic deformation of the elastic biasing portion 1 absorbs the thickness tolerances of the plurality of power modules 3. Similarly, the improvement in adhesion due to the elastic deformation of the elastic biasing portion 1 reduces the possible bypass flow of the refrigerant generated from the clearance between the cover 2 and the heat dissipation fin 9, and improves the flow velocity of the refrigerant flowing through the flow path 22, thereby improving the cooling performance (heat transfer rate) of the device 100. Further, by pressurizing the heat dissipation fin 9 toward the power module 3, the TIM 5 is thinned and the vibration resistance is improved.

[0018] (Figure 3) The process of pressurizing the power module 3 (package) by the elastic deformation of the elastic biasing portion 1 is shown. The elastic biasing portion 1 before biasing is made of a material such as aluminum or a spring elastic material and is formed in a wave shape on the cover 2 (Fig. 3(a)). When the cover 2 and the frame 8 are fastened by the connecting member 15 here, the elastic biasing portion 1 is deformed. After the deformation of the elastic biasing portion 1, the contact area between the elastic biasing portion 1 and the heat dissipation fin 9 increases (Fig. 3(b)). The heat dissipation fin 9 is formed of a high heat conduction member such as aluminum or copper. The connecting member 15 is a fixing member such as a screw.

[0019] If the power module 3 is not an individual package, the present invention is also applicable to a form in which it is joined to the frame 8 by FSW or welding. The connection by the connecting member 15 does not have to be a screw. Also, the heat dissipation fin 9 and the cover 2 may be brazed. Further, a configuration in which the cover 2 is biased and pressed using another component mounted on the semiconductor device 100 from the biasing side may be used.

[0020] The connecting member 15 is screwed to the four corners of the elastic biasing portion 1 (see Fig. 1). Thereby, the elastic biasing portion 1 can secure a pressing force against the plurality of power modules 3. Also, the heat dissipation base 12 can improve the bonding reliability.

[0021] By doing so, the heat dissipation fins 9 are grounded to the elastic biasing portion 1, and the operating noise can be reduced, so that noise countermeasures and vibration suppression can be achieved.

[0022] (Verification of the effects of the invention by comparison with the prior art) A structure that has been conventionally used, a structure in which an extruded fin is brazed and assembled by screwing, and a structure used in the present invention, a structure in which a forged pin fin and a liquid seal member are used in a sheet metal case and assembled by screwing, were compared and verified. In terms of cost, it was possible to reduce the cost compared to the prior art due to the three-part heat dissipation fins 9 of the present invention. The heat transfer rate of the heat dissipation fins 9 was equivalent. Regarding the variation in the thickness of TIM5 of each power module 3, the prior art could not improve it to below the target variation value (160 μm), but it was found that the present invention could achieve improvement below the target value and reduce the variation.

[0023] (First modified example) (Fig. 4) The power module 3 is composed of a semiconductor element 18, a first circuit body 17, and a second circuit body 19. By using the first circuit body 17 and the second circuit body 19 as heat dissipation circuit bodies, the power module 3 can be cooled from both sides via the heat dissipation base 12 and the heat dissipation fins 9.

[0024] (Second modified example) (Fig. 5) A plurality of power modules 3 and 4 are simultaneously arranged corresponding to the heat dissipation base 12. When the heat dissipation base 12 corresponds to a large number of miniaturized power modules 3 and 4, the pressure on the joint portion can be reduced while maintaining the pressure on the power modules 3 and 4, so that the reliability can be improved.

[0025] (Third modified example) (Fig. 6) The power module 3 is mounted on the printed circuit board 20 having the board through-hole 20a (board opening), so that the assemblability and heat dissipation including the printed circuit board 20 can be improved, and further, it is possible to easily obtain the reference plane 21 described later.

[0026] (Fourth Modification Example) (Fig. 7) As described above, the power module 3 is mounted on the printed circuit board 20, and the lower surface thereof is arranged to be aligned with a predetermined reference plane 21. Thereby, it becomes possible to set the lower surface of the power module 3 to a unified height, and it becomes possible to arrange a plurality of power modules 3 with respect to one heat dissipation base 12. On the other hand, on the upper surface on the opposite side via the power module 3 from the reference plane 21, due to the thickness tolerance of each power module 3, it does not become a uniform surface. Therefore, on the upper surface on the opposite side of the reference plane 21, by arranging the power modules 3 one by one with respect to one heat dissipation base 12, the thickness tolerance (variation) of the power module 3 can be absorbed by the elastic biasing portion 1 on one side of the power module 3 when the cover 2 is pressurized.

[0027] (Flow Path Structure of Semiconductor Device) (Fig. 8) The flow path 22 is arranged in a U-shape (the bottom part of the U is on the right side in Fig. 8) on the printed circuit board 20, and the flow path inlet 11a and the flow path outlet 11b are installed on the same side (the left side in Fig. 8) of the board 20. Further, the flow path 22 flowing from the flow path inlet 11a and the flow path 22 flowing toward the flow path outlet 11b are arranged evenly on the left and right. Thereby, the floor area of the printed circuit board 20 is reduced.

[0028] The flow path 22 flowing from the flow path inlet 11a is arranged on the IGBT 3b side with a large heat dissipation amount among the semiconductor elements of the power module 3. On the other hand, the flow path 22 leading to the flow path outlet 11b is arranged on the diode 3a side with a small heat dissipation amount among the power modules 3. Thereby, the cooling effect is improved.

[0029] (Fifth Modification Example) (Fig. 9) When a semiconductor element 18 that requires uniform cooling, such as SiC (silicon carbide), is mounted on the substrate 20, the U-shaped flow path 22 is divided into a flow path 22a side where the semiconductor elements 18 are concentrated and the heat generation amount is large, and a flow path 22b side where the arrangement of the semiconductor elements 18 is less than that on the flow path 22a side and the heat generation amount is low. At this time, the flow path width of the flow path 22a through which the refrigerant flowing in from the flow path inlet 11a flows is larger than that of the flow path 22b flowing in the opposite direction on the opposite side of the substrate 20. Further, the heat dissipation fins 9 are not provided on the flow path 22b that does not pass near the semiconductor element 18. Thereby, the pressure loss is reduced.

[0030] (Sixth modification example) (FIG. 10) An elastic member 24 is disposed at the tip of the heat dissipation fin 9. Thereby, when the cover 2 is pressurized with respect to the heat dissipation fin 9 via the elastic member 24, when the deformation amount of the elastic biasing portion 1 of the cover 2 is insufficient, the elastic member 24 can replenish the gap (clearance), and by enhancing the adhesion, the cooling performance can be improved.

[0031] (Seventh modification example) (FIG. 11) The heat dissipation fin 9 is joined to the cover 2 with a brazing material 25 or the like. Thereby, the brazing material 25 replenishes the gap (clearance) that can be formed at the tip of the heat dissipation fin 9 when the cover 2 is pressurized, thereby reducing the gap and absorbing the variation in the height of the heat dissipation fin 9.

[0032] (Eighth modification example) (FIG. 12) The heat dissipation fin 9 has a plurality of fin portions, respectively, and the height of the fin portion 9b disposed on the outer peripheral side thereof is larger than that of the fin portion 9a disposed on the central side thereof. By doing so, when the deformation amount of the elastic biasing portion 1 is small when the cover 2 is pressurized, the gap (clearance) generated at the tip portion of the heat dissipation fin 9 can be reduced.

[0033] According to one embodiment of the present invention described above, the following operational effects are achieved.

[0034] (1) The semiconductor device 100 includes a plurality of power modules 3 each having a semiconductor element 18, a plurality of heat dissipation bases 12 disposed via a heat dissipation member 5 on the heat dissipation surface side of the plurality of power modules 3 and having heat dissipation fins 9, a frame 8 having a plurality of openings 8a, and a cover 2 that forms a refrigerant flow path by covering the heat dissipation bases 12 and the frame 8. In this semiconductor device 100, the plurality of heat dissipation bases 12 each block the plurality of openings 8a, and the cover 2 has an elastic biasing portion 1 on the surface that contacts the heat dissipation fins 9, and biases the heat dissipation bases 12 by pressing them toward the power module 3. By doing so, it is possible to provide a semiconductor device 100 that achieves both productivity and heat dissipation performance.

[0035] (2) The heat dissipation base 12 blocks the opening 8a via a seal member 7, and the seal member 7 is made of a material that can be deformed in the direction from the heat dissipation base 12 to the power module 3. By doing so, the adhesion of the opening 8a is improved.

[0036] (3) The heat dissipation bases 12 are disposed on both sides of the power module 3. By doing so, the cooling performance is improved.

[0037] (4) At the four corners around the biasing portion 1, screw fastening portions 15 are respectively provided. By doing so, the pressing force is ensured and the connection reliability is improved.

[0038] (5) The heat dissipation base 12 blocks the opening 8a. By doing so, the bonding reliability is improved.

[0039] (6) A plurality of power modules 3 and 4 are arranged with respect to one heat dissipation base 12. By doing so, while maintaining the pressing force, the pressure on the joint portion can be reduced, so that the reliability can be improved.

[0040] (7) The plurality of power modules 3 and 4 are mounted on the printed circuit board 20. By doing so, the assemblability and heat dissipation performance can be improved, and furthermore, it becomes easier to obtain a reference plane 21.

[0041] (8) The plurality of power modules 3 and 4 are mounted on the printed circuit board 20 such that one side thereof is aligned with a predetermined reference plane 21. On one side of the plurality of power modules 3 and 4, a plurality of power modules 3 and 4 are arranged with respect to one heat dissipation base, and on the other side of the plurality of power modules 3 and 4, the power modules 3 (4) are arranged one by one with respect to one heat dissipation base. By doing so, when the cover 2 is pressurized, the thickness tolerance (variation) of the power module 3 can be absorbed on one side of the power module 3.

[0042] (9) The plurality of power modules 3a and 3b have different heat generation amounts from each other, and the refrigerant flow path 22 is formed such that the flow path is directed from the power module 3b with a larger heat generation to the power module 3a with a smaller heat generation. By doing so, the cooling effect is improved.

[0043] (10) The refrigerant flow path 22 has flow paths 22a and 22b flowing in opposite directions to each other, and among the flow paths, one flow path 22a has a larger flow path width than the other flow path 22b. By doing so, the pressure loss is reduced.

[0044] (11) An elastic member 24 is arranged between the heat dissipation fins 9 and the cover 2. By doing so, the cooling performance can be improved.

[0045] (12) A brazing material 25 is arranged between the heat dissipation fins 9 and the cover 2. By doing so, the variation in the height of the heat dissipation fins 9 can be absorbed.

[0046] (13) The heat radiating fin 9 has a plurality of fin portions 9a and 9b. Among the fin portions 9a and 9b of the heat radiating fin 9, the fin portion 9b on the outer peripheral side has a greater fin height than the fin portion 9a on the central side. By doing so, when the deformation amount of the elastic biasing portion 1 is small during the pressurization of the cover 2, the clearance generated at the tip portion of the heat radiating fin 9 can be reduced.

[0047] Note that the present invention is not limited to the above-described embodiments, and various modifications and combinations with other configurations can be made without departing from the gist thereof. Further, the present invention is not limited to the one including all the configurations described in the above embodiments, and also includes the one in which a part of the configuration is deleted.

Explanation of Reference Numerals

[0048] 100: Semiconductor device 1: Elastic biasing portion 2: Cover 3, 4: Power module 3a: Diode 3b: IGBT 5: Heat radiating member (TIM) 6: Insulating member 7: Joining member (sealing member) 8: Frame 8a: Through hole (opening) 9: Heat radiating fin 9a: Short fin portion 9b: Long fin portion 10: Pipe component 11: Flow path inlet / outlet 11a: Flow path inlet 11b: Flow path outlet 12: Heat radiating base 14: Fixing member 15: Connecting member 16: Sealing member (sealing member) 17: First circuit body 18: Semiconductor element 19: Second circuit body 20: Printed circuit board 20a: Board through hole (board opening) 21: Reference plane 22: Flow path 22a: Thick flow path 22b: Narrow flow path 23: SiC 24: Elastic member 25: Brazing material

Claims

1. A plurality of power modules having semiconductor elements, a plurality of heat dissipation bases disposed via a heat dissipation member on the heat dissipation surface side of the plurality of power modules and having heat dissipation fins, a frame having a plurality of openings, and a cover that forms a refrigerant flow path by covering the heat dissipation base and the frame, wherein the plurality of heat dissipation bases each close the plurality of openings, the cover has an elastic biasing portion on a surface that contacts the heat dissipation fins, and biases the heat dissipation base by pressing the heat dissipation base toward the power module A semiconductor device.

2. In the semiconductor device according to Claim 1, the heat dissipation base closes the opening via a sealing member, and the sealing member is made of a material that is deformable in the direction from the heat dissipation base to the power module A semiconductor device.

3. In the semiconductor device according to Claim 1, the heat dissipation base is disposed on both surfaces of the power module A semiconductor device.

4. In the semiconductor device according to Claim 1, screw fastening portions are respectively provided at four corners around the biasing portion A semiconductor device.

5. In the semiconductor device according to Claim 1, the heat dissipation base closes the opening A semiconductor device.

6. In the semiconductor device according to Claim 1, a plurality of the power modules are arranged with respect to one heat dissipation base A semiconductor device.

7. In the semiconductor device according to Claim 1, the plurality of power modules are mounted on a printed circuit board A semiconductor device.

8. In the semiconductor device according to Claim 7, the plurality of power modules are mounted on the printed circuit board so that one surface side is aligned with a predetermined reference surface, on the one surface side of the plurality of power modules, a plurality of the power modules are arranged with respect to one heat dissipation base, on the other surface side of the plurality of power modules, the power modules are arranged one by one with respect to one heat dissipation base A semiconductor device.

9. In the semiconductor device according to Claim 1, the plurality of power modules have different heat generation amounts from each other, and the refrigerant flow path is formed from the power module with a larger heat generation to the power module with a smaller heat generation A semiconductor device.

10. In the semiconductor device according to Claim 1, The refrigerant flow path has flow paths flowing in opposite directions to each other. Among the flow paths, one of the flow paths has a larger flow path width than the other flow path. Semiconductor device.

11. In the semiconductor device according to claim 1, An elastic member is disposed between the heat dissipation fin and the cover. Semiconductor device.

12. In the semiconductor device according to claim 1, A brazing material is disposed between the heat dissipation fin and the cover. Semiconductor device.

13. In the semiconductor device according to claim 1, The heat dissipation fin has a plurality of fin portions. Among the fin portions of the heat dissipation fin, the fin portion on the outer peripheral side has a larger fin height than the fin portion on the central side. Semiconductor device.

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