JP2014225571A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device which can inhibit pump out thereby to improve thermal reliability.SOLUTION: A semiconductor device comprises: a heat sink 20; semiconductor modules 30, 31, 32 each having a heat dissipation metal 37 on a rear face; metal plates 40, 41, 42 which are bonded to arrangement regions of the semiconductor modules on the heat sink and each has a linear expansion coefficient closer to a linear expansion coefficient of the heat dissipation metal than a linear expansion coefficient of the heat sink; and a leaf spring 60 for depressing a heat dissipation metal side of the semiconductor module to the metal plate of the heat sink via heat dissipation greases 50, 51, 52.

Description

  The present invention relates to a semiconductor device including a semiconductor module and a cooler.

  In Patent Document 1, the semiconductor module is pressed against and fixed to a heat sink or heat sink by a pressing plate spring and its reinforcing beam, and the pressing plate spring and its reinforcing beam are fixed to the heat sink or heat sink with screws. In the semiconductor module, the semiconductor element is resin-sealed and a screw through hole is provided in the center.

  In Patent Document 2, a semiconductor module, a cooler that is provided on the surface of the semiconductor module and cools the semiconductor module, and a heat transfer member that is provided between the semiconductor module and the cooler and has thermal conductivity, Is provided. A recess is formed on at least one of the surface of the semiconductor module facing the cooler or the surface of the cooler facing the semiconductor module outside the region where the heat transfer member is provided. Since the gap between the semiconductor module and the cooler is expanded by this recess, it becomes difficult for the heat transfer member to be swept out of the cooling region between the semiconductor module and the cooler. The performance can be maintained.

JP 2007-329167 A JP2013-12520A

  By the way, when the heat sink on which the semiconductor module back surface and the semiconductor module are pressed is made of a different material such as copper and aluminum, the heat radiation grease arranged between the semiconductor module and the heat sink is cooled by the difference in linear expansion coefficient between the different materials. The cycle is easy to pump out and the thermal reliability is lowered.

  An object of the present invention is to provide a semiconductor device capable of improving thermal reliability by suppressing pump-out.

  In the first aspect of the invention, the cooler, the semiconductor module having the heat dissipating metal on the back surface, and the heat dissipating metal wire joined to the arrangement region of the semiconductor module in the cooler, and the linear expansion coefficient of the cooler. The gist is provided with a metal plate close to an expansion coefficient and pressing means for pressing the heat radiating metal side of the semiconductor module against the metal plate of the cooler via heat radiating grease.

  According to invention of Claim 1, a metal plate is joined to the arrangement | positioning area | region of the semiconductor module in a cooler, and is closer to the linear expansion coefficient of a thermal radiation metal than the linear expansion coefficient of a cooler. Then, the heat dissipation metal side of the semiconductor module is pressed against the metal plate of the cooler via the heat dissipation grease by the pressing means. At this time, the heat-dissipating grease is arranged between the heat-dissipating metal of the semiconductor module and the metal plate closer to the heat-dissipating metal than the linear expansion coefficient of the cooler. In addition, the pump-out can be suppressed and the thermal reliability can be improved.

  According to a second aspect of the present invention, in the semiconductor device according to the first aspect, when the metal plate has a concave portion that opens to the semiconductor module side on the surface facing the semiconductor module, the pump-out is further suppressed. Thermal reliability can be improved.

  According to a third aspect of the present invention, in the semiconductor device according to the first or second aspect, a pump is provided with a radiating grease reservoir chamber between the side surface of the metal plate and the cooler around the metal plate. Out reliability can be further suppressed to improve thermal reliability.

According to a fourth aspect of the present invention, in the semiconductor device according to the second aspect of the present invention, a plurality of the recesses may be provided on the metal plate.
According to a fifth aspect of the present invention, in the semiconductor device according to the second aspect of the present invention, the concave portion may have an annular shape.

  According to the present invention, pump-out can be suppressed and thermal reliability can be improved.

(A) is a top view of the semiconductor device in an embodiment, (b) is a left view of a semiconductor device, and (c) is a front view of a semiconductor device. (A) is a longitudinal cross-sectional view in the AA line of Fig.1 (a), (b) is an enlarged view in the B section of (a). The top view of the semiconductor device in the state where the circuit board for control was removed. The top view of a semiconductor device in the state where a circuit board for control and a spring retainer bracket were removed. The top view of a semiconductor device in the state where a circuit board for control, a spring retainer bracket, and a leaf spring were removed. (A) is a top view which shows a heat sink and a metal plate, (b) is a longitudinal cross-sectional view in the AA line of (a), (c) is a longitudinal cross-sectional view in the BB line of (a). (A) is a schematic longitudinal cross-sectional view for demonstrating a heat sink and a metal plate, (b) is an enlarged view in the D section of (a). The disassembled perspective view of a semiconductor device. The schematic longitudinal cross-sectional view for demonstrating the manufacturing process of a semiconductor device. The schematic longitudinal cross-sectional view for demonstrating the manufacturing process of a semiconductor device. (A) is a top view which shows the metal plate of another example, (b) is a longitudinal cross-sectional view in the AA line of (a). The schematic longitudinal cross-sectional view which shows the semiconductor device for a comparison. The schematic longitudinal cross-sectional view which shows the semiconductor device for a comparison.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
In the drawings, the horizontal plane is defined by the orthogonal X and Y directions, and the vertical direction is defined by the Z direction.

  As shown in FIGS. 1, 2, and 8, the semiconductor device (inverter) 10 includes an aluminum heat sink 20 as a cooler, semiconductor modules 30, 31, and 32, copper metal plates 40, 41, and 42, The heat dissipating grease 50, 51, 52, the leaf spring 60, and the spring holding bracket 70 are provided. The semiconductor modules 30, 31, and 32 have a copper radiating metal 37 on the back surface (lower surface), and are disposed on the heat sink 20. The leaf spring 60 is disposed on the semiconductor modules 30, 31, and 32, and presses the heat radiating metal 37 side of the semiconductor modules 30, 31, and 32 to the heat sink 20. The spring retainer bracket 70 is disposed on the leaf spring 60 and supports the leaf spring 60.

A spring retainer bracket 70 as a pressing means is fastened and fixed to the heat sink 20 with screws 80. This generates a spring load.
As shown in FIGS. 1 and 3, fastening bosses 75 a to 75 f are integrally formed on the lower surface of the spring retainer bracket 70. Specifically, the spring pressing bracket 70 having a rectangular plate shape has a long side extending in the X direction, and the semiconductor modules 30, 31, and 32 are arranged in the X direction, but outside the portion corresponding to the semiconductor module 30 on one end side. Further, a fastening boss 75a is provided in a protruding manner, and a fastening boss 75b is provided outside the portion corresponding to the semiconductor module 32 on the other end side. Further, fastening bosses 75c and 75d are provided on the lower surface of the spring retainer bracket 70 so as to protrude apart from each other in the Y direction between a portion corresponding to the semiconductor module 30 and a portion corresponding to the semiconductor module 31. Further, fastening bosses 75e and 75f are provided on the lower surface of the spring retainer bracket 70 so as to project apart from each other in the Y direction between a portion corresponding to the semiconductor module 31 and a portion corresponding to the semiconductor module 32. The fastening bosses 75 a to 75 f are cylindrical, and the tips of the fastening bosses 75 a to 75 f are in contact with the heat sink 20.

  As shown in FIG. 6, the aluminum heat sink 20 includes a square plate-like main body portion 21, and a plurality of plate-like fin portions 22 are projected from the lower surface of the main body portion 21. The upper surface has a rectangular shape in plan view, and its long side extends in the X direction in the horizontal direction and its short side extends in the Y direction in the horizontal direction. The heat sink 20 is formed thin in the vertical direction (Z direction).

  Concave portions 23, 24, and 25 are formed in regions corresponding to the placement portions of the semiconductor modules 30, 31, and 32 on the upper surface of the square plate-shaped main body portion 21 of the heat sink 20. As shown in FIG. 7, the depths (t1) of the recesses 23, 24, 25 are about 1 mm. Metal plates 40, 41, 42 are disposed inside the recesses 23, 24, 25. The bottom surfaces of the recesses 23, 24, 25 and the metal plates 40, 41, 42 are joined together by brazing or the like. Yes. Thus, the metal plates 40 to 42 are joined to the arrangement region of the semiconductor modules 30 to 32 in the heat sink 20.

  As shown in FIG. 6, seating portions 26 a to 26 f on which the fastening bosses 75 a to 75 f are seated at portions corresponding to the fastening bosses 75 a to 75 f of the spring retainer bracket 70 on the upper surface of the main body portion 21 of the heat sink 20. Projected. That is, the seating portion 26a is formed outside the placement portion (metal plate 40) of the semiconductor module 30 on one end side in the X direction, which is the parallel arrangement direction of the semiconductor modules 30, 31, 32, and at the other end side. A seating portion 26b is formed outside the mounting portion (metal plate 42) of the semiconductor module 32. Furthermore, seating portions 26c and 26d are formed on the upper surface of the main body portion 21 so as to be separated in the Y direction between the mounting portion (metal plate 40) of the semiconductor module 30 and the mounting portion (metal plate 41) of the semiconductor module 31. Has been. In addition, on the upper surface of the main body 21, seating portions 26e and 26f are formed in the Y direction between the mounting portion (metal plate 41) of the semiconductor module 31 and the mounting portion (metal plate 42) of the semiconductor module 32. Has been.

  As shown in FIG. 5, three semiconductor modules 30, 31, and 32 are arranged in the length direction (X direction) of the heat sink 20 on the heat sink 20. Each of the semiconductor modules 30, 31, 32 is placed on the heat sink 20 on the metal plates 40, 41, 42 via heat radiation grease (silicone grease, etc.) 50, 51, 52.

  The semiconductor module 30 incorporates (resin-sealed) an upper arm configuration power transistor and a lower arm configuration power transistor in the U phase. The semiconductor module 31 incorporates (resin-sealed) an upper arm configuration power transistor and a lower arm configuration power transistor in the V phase. The semiconductor module 32 incorporates (resin-sealed) an upper arm configuration power transistor and a lower arm configuration power transistor in the W phase. The power transistor is a MOSFET, an IGBT, or the like. In each semiconductor module 30, 31, 32, the upper arm power transistor and the lower arm power transistor are connected in series (connected), and one power (positive input) and the other end (negative input) of the series circuit and both powers. The transistor (output) is connected to the outside.

  As shown in FIG. 5, each of the semiconductor modules 30, 31, and 32 includes a plate-like positive electrode terminal 34, a plate-like negative electrode terminal 35, and a plate-like output terminal 36. Each of the semiconductor modules 30, 31, and 32 includes a control signal pin (not shown).

  As shown in FIG. 4, a leaf spring 60 is disposed on each semiconductor module 30, 31, 32. The leaf spring 60 is made of a spring steel plate and extends in the X direction as a whole in plan view. The leaf spring 60 has main body portions 63a, 63b, and 63c for the semiconductor modules 30, 31, and 32, respectively. That is, the three main body portions 63a, 63b, and 63c are arranged side by side in the X direction in plan view. Each body part 63a, 63b, 63c is configured such that both side parts 62 extend from a horizontal central part 61, and both side parts 62 are bent obliquely downward. Both side portions 62 extend from the central portion 61 in the Y direction, and the leaf spring 60 has both side portions 62 that extend from the central portion 61 in directions away from each other and are in contact with the semiconductor module.

  Horizontal connecting portions 64, 65, 66, and 67 are juxtaposed on each of the main body portions 63a, 63b, and 63c. Each of the main body portions 63a, 63b, and 63c is predetermined so as to apply a pressing force to the vicinity of the central portion of each of the semiconductor modules 30, 31, and 32 when the leaf spring 60 is disposed above the semiconductor modules 30, 31, and 32. Are provided at intervals.

  As shown in FIG. 3, a spring holding bracket 70 is disposed on the upper part of the leaf spring 60. The spring retainer bracket 70 is made of a metal plate material such as aluminum. As shown in FIG. 3, the spring retainer bracket 70 has a rectangular plate shape extending in the X direction in plan view. The spring retainer bracket 70 is fastened and fixed to the heat sink 20 by screwing screws 80 passing through the fastening bosses 75 a to 75 f into the heat sink 20.

  Specifically, as shown in FIG. 2 (b), screws 80 that pass through fastening bosses (cylindrical protrusions) 75a to 75f of the spring retainer bracket 70 are screwed into the heat sink 20, whereby the spring retainer bracket 70 is moved to the heat sink. 20 is fixed.

  Further, fastening bosses 75a to 75f are arranged on both sides of the semiconductor modules 30, 31, and 32 in the X direction, which is a parallel arrangement direction of the plurality of semiconductor modules, and the fixing points of the spring holding bracket 70 are the semiconductor modules 30, 31, 32 at both ends. Therefore, compared with the case where only the both ends in the juxtaposed direction (X direction) of the plurality of semiconductor modules are fixed points of the spring retainer bracket 70, the distance between the both ends in the juxtaposed direction (X direction) of the plurality of semiconductor modules. Since the fixing point of the spring pressing bracket 70 exists also in the part, the deformation of the spring pressing bracket 70 due to the spring reaction force of the leaf spring 60 is suppressed. Thereby, size reduction, weight reduction, and cost reduction of the spring retainer bracket 70 are achieved.

  The leaf spring 60 placed on the upper part of the semiconductor modules 30, 31, 32 is pressed and deformed from above by the spring retainer bracket 70 being fastened and fixed to the heat sink 20. Thereby, each semiconductor module 30, 31, 32 is fixed by being pressed downward by the downward biasing force of the leaf spring 60.

  As shown in FIG. 2, a control circuit board 90 is disposed on the upper part of the spring retainer bracket 70. As shown in FIGS. 1 and 3, a plurality of pillar portions 76 are formed on the upper surface of the spring retainer bracket 70, and the control circuit board 90 is placed on the plurality of pillar portions 76. The control circuit board 90 is fastened and fixed to the spring retainer bracket 70 by screwing the screw 100 penetrating the control circuit board 90 into the column portion 76 of the spring retainer bracket 70.

  The control circuit board 90 is electrically connected to control signal pins (not shown) of the semiconductor modules 30, 31 and 32. Between the control circuit board 90 and the semiconductor modules 30, 31, and 32, a spring pressing bracket 70 made of a metal plate material such as aluminum is positioned, and the spring pressing bracket 70 functions as a shield material. That is, the spring retainer bracket 70 also serves as a shield material.

  The semiconductor device 10 is assembled so that the heat sink 20, the three semiconductor modules 30, 31, 32, the leaf spring 60, the spring holding bracket 70, and the control circuit board 90 are stacked in this order. The semiconductor device 10 is fixed in a state where the semiconductor modules 30, 31, and 32 are pressed against the upper surface of the heat sink 20 by the action of the leaf spring 60 and the spring holding bracket 70. In the semiconductor device 10, the semiconductor modules 30, 31 and 32 are cooled by the action of the heat sink 20.

  As shown in FIGS. 6 and 7, the metal plates (copper plates) 40, 41, 42 have a quadrangular shape in plan view, and the thickness t1 is about 1 mm. The metal plates 40, 41, 42 have upper surfaces facing the semiconductor modules 30, 31, 32, and a plurality of shallow recesses (grooves) 45 are provided on the upper surface. The recess 45 opens to the semiconductor modules 30, 31, 32 side on the upper surface of each metal plate 40, 41, 42, that is, the surface facing the semiconductor modules 30, 31, 32. The recess 45 has a quadrangular shape in plan view. The recess 45 is formed on the upper surface of the metal plates 40, 41, 42 in an aligned state in the X and Y directions. As shown in FIG. 7, the depth d1 of the recess 45 is about 100 μm. As shown in FIG. 2B, heat radiation grease 50, 51, 52 enters the recess 45.

  As shown in FIG. 7, the metal plates 40, 41, 42 are arranged in the recesses 23, 24, 25 of the main body 21 of the heat sink 20, but the recesses 23, 24, 25 are located more than the metal plates 40, 41, 42. Largely formed. Accordingly, a gap is formed between the outer peripheral surface of the metal plates 40, 41, 42 and the side surfaces of the recesses 23, 24, 25. This gap (space) serves as a heat-absorbing grease reservoir chamber R1, and heat-absorbing greases 50, 51, and 52 are accumulated in the reservoir chamber R1 as shown in FIG. As shown in FIG. 7B, the heat-absorbing grease reservoir chamber R1 is formed to have a constant width L1 (specifically, about 1 mm) over the entire circumference of the metal plates 40, 41, and. In this way, the heat-absorbing grease reservoir chamber R <b> 1 is provided between the side surfaces of the metal plates 40, 41, 42 and the heat sink 20 around the metal plates 40, 41, 42.

  The metal plates 40, 41, and 42 are made of copper, the heat dissipating metal 37 on the back surfaces (lower surfaces) of the semiconductor modules 30 to 32 is made of copper, and the heat sink 20 is made of aluminum. The linear expansion coefficient of copper is about 17 ppm / ° C., and the linear expansion coefficient of aluminum is about 27 ppm / ° C. Therefore, the metal plates 40, 41, and 42 are joined to the arrangement region of the semiconductor modules 30, 31, and 32 in the heat sink 20, but the metal plates 40, 41, and 42 radiate heat from the lower surface of the semiconductor module due to the linear expansion coefficient of the heat sink 20. It is close to the linear expansion coefficient of the metal 37.

  Then, as shown in FIG. 9, the heat dissipation grease 50, 51, 52 is applied to the heat dissipation metal 37 of the semiconductor module, and the metal plates 40, 41, 42 are joined to the heatsink 20. The semiconductor modules 30, 31, 32 (heat radiation grease 50, 51, 52) are placed on the (metal plates 40, 41, 42). At this time, the thickness of the heat dissipating grease 50, 51, 52 is about 150 μm. When the leaf spring 60 and the spring retainer bracket 70 are arranged on the semiconductor modules 30, 31, and 32 and the spring retainer bracket 70 is fastened to the heat sink 20 with the screws 80, a spring load is generated. As a result, as shown in FIG. 10, the heat radiation metal 37 side of the semiconductor modules 30, 31, 32 is pressed against the metal plates 40, 41, 42 of the heat sink 20 via the heat radiation grease 50, 51, 52 by the leaf spring 60. . At this time, the thickness of the heat dissipating grease 50, 51, 52 is about 50 μm, and the heat dissipating grease 50, 51, 52 enters the recess 45 and also enters the reservoir chamber R1.

  Therefore, there is no difference in linear expansion coefficient between the copper heat radiating metal 37 and the copper metal plates 40 to 42, and the movement of the structure in the heat radiating grease 50, 51, 52 due to the heat cycle is suppressed. Thereby, pump-out is suppressed. Further, the heat radiation grease 50, 51, 52 enters the recess 45 of the metal plates 40-42, so that the contact length of the heat radiation grease 50, 51, 52 with the metal plates 40-42 is increased (the contact area is increased), When an external stress is applied, the heat dissipating greases 50, 51, and 52 become difficult to move. Further, since the extruded heat radiation greases 50, 51, 52 are accumulated in the accumulation chamber R1, displacement of the heat radiation greases 50, 51, 52 is prevented.

Next, the operation of the semiconductor device 10 configured as described above will be described.
The leaf spring 60 is disposed on the upper surface of the semiconductor modules 30, 31, 32, and a load is generated by the spring retainer bracket 70 being fastened to the heat sink 20 by the spring retainer bracket fastening screw 80.

  In the semiconductor device 10, the semiconductor modules 30, 31, 32 generate heat as the semiconductor modules 30, 31, 32 are driven. This heat is released from the heat dissipating metal 37 on the back surface to the heat sink 20 via the heat dissipating grease 50, 51, 52. For example, when such a heat cycle is applied, it is possible to prevent pump-out in the heat dissipating grease 50, 51, 52. That is, as a comparative example, as shown in FIG. 12, when the semiconductor module 210 is disposed on the upper surface of a flat heat sink 200 via the heat radiation grease 220 and pressed from above, it is as follows.

  When a thermal cycle is applied as shown by a chain line in FIG. 13, the heat dissipating grease 220 repeatedly expands and contracts, and the heat dissipating grease 220 moves between the lower surface of the semiconductor module 210 and the upper surface of the heat sink 200 and air (bubbles) is contracted. Is trapped in the heat dissipating grease 220 and air remains during expansion (taken into the grease). As a result, the heat radiation performance between the lower surface of the semiconductor module 210 and the heat sink 200 is degraded.

  On the other hand, in the present embodiment, the intake of air (bubbles) in the heat dissipation greases 50, 51, and 52 is suppressed, and a decrease in heat dissipation performance between the lower surface of the semiconductor module and the heat sink can be prevented.

  That is, the heat radiation grease (silicone grease or the like) 50, 51, 52 between the semiconductor modules 30, 31, 32 and the heat sink 20 is difficult to pump out due to thermal stress. Specifically, metal plates (copper plates) 40, 41, and 42 having shallow recesses (grooves) 45 of about 100 μm on the upper surface are joined to the heat sink 20 by brazing or the like, and the heat sink 20 and the metal plates 40, 41, 42 is provided with a reservoir chamber (gap) R1 of heat radiation grease 50, 51, 52 having a width L1 of about 1 mm.

  In this way, by providing the metal plates (copper plates) 40, 41, 42 having a thermal expansion coefficient closer to the heat radiating metal 37 than the heat sink 20 on the heat sink 20, the back surface of the semiconductor module on which the heat radiating grease 50, 51, 52 is interposed The difference in coefficient of linear expansion between the heat sink and the heat sink is eliminated, and displacement of the heat-dissipating grease 50, 51, 52 due to thermal stress is suppressed (pump-out generated when a heat cycle is applied is suppressed).

  Further, the shallow recesses (grooves) 45 provided on the metal plates 40, 41, and 42 increase the contact length of the heat-dissipating greases 50, 51, and 52, and during external stress (for example, thermal cycle or vibration cycle). Even if the same stress is applied, the heat-dissipating greases 50, 51, and 52 are less likely to flow, and as a result, displacement of the heat-dissipating greases 50, 51, and 52 due to external stress is suppressed.

  Furthermore, the heat-dissipating grease 50, 51, 52 is pushed out by external stress due to the accumulation chamber (gap) R 1 of the heat-dissipating grease 50, 51, 52 provided between the metal plates 40, 41, 42 and the heat sink 20. Is suppressed. Even if it is pushed out, it is possible to prevent the heat radiation grease 50, 51, 52 from being sucked out of the accumulation chamber R1 during the subsequent contraction and entraining air (bubbles).

By these, it leads to suppression of pump-out and contributes to thermal reliability improvement.
According to the above embodiment, the following effects can be obtained.
(1) As a structure of the semiconductor device, a heat sink 20 as a cooler, semiconductor modules 30, 31, and 32 having a heat radiating metal 37 on the back surface, metal plates 40, 41, and 42, and a leaf spring 60 as a pressing means . The metal plates 40, 41, and 42 as buffer materials are joined to the semiconductor module arrangement region in the heat sink 20 and are closer to the linear expansion coefficient of the heat radiating metal 37 than the linear expansion coefficient of the heat sink 20. The leaf spring 60 presses the heat dissipation metal 37 side of the semiconductor modules 30, 31, 32 against the metal plates 40, 41, 42 of the heat sink 20 via the heat dissipation grease 50, 51, 52. Therefore, the heat radiating grease 50, 51, 52 is arranged between the heat radiating metal 37 of the semiconductor module and the metal plates 40, 41, 42 that are closer to the linear expansion coefficient of the radiating metal 37 than the linear expansion coefficient of the heat sink 20. The difference in coefficient of linear expansion is small. Thereby, pump-out can be suppressed and thermal reliability can be improved.

  (2) The metal plates 40, 41, 42 have a recess 45 that opens to the semiconductor module side on the surface facing the semiconductor modules 30, 31, 32. Therefore, pump-out can be further suppressed and thermal reliability can be improved.

  (3) In the periphery of the metal plates 40, 41, 42, there is a reservoir chamber (R 1) for heat radiation grease 50, 51, 52 between the side surfaces of the metal plates 40, 41, 42 and the heat sink 20. Therefore, pump-out can be further suppressed and thermal reliability can be improved.

(4) Since the spring retainer bracket 70 is fixed to the heat sink 20, the semiconductor modules 30, 31, and 32 are not restricted (through holes or the like).
The embodiment is not limited to the above, and may be embodied as follows, for example.

  The concave portions 45 of the metal plates 40, 41, and 42 have a quadrangular shape in plan view and are arranged in parallel in the X and Y directions. However, the present invention is not limited to this. For example, FIG. As shown, it may be a recess 46 formed in a square ring shape on the upper surface of the metal plate 43. That is, the recess may be annular. Moreover, the planar view of the recessed part 45 does not need to be square shape, and the contact length with grease should just become long compared with the case where the recessed part 45 is not provided.

  Although the heat sink 20 is used as a cooler, a heat sink (block), a case-integrated fin, or the like may be used, or a water-cooled cooler may be used instead of the air-cooled heat sink 20.

  The spring retainer bracket 70 is fastened and fixed to the heat sink 20, but is not limited thereto. For example, the cooler may be fixed to the case, and the spring holding bracket 70 may be fixed to the case.

-Although the screw is fixed as a fixing method of the spring retainer bracket 70, it may be fixed by caulking or the like.
In the above-described embodiment, three semiconductor modules are illustrated, but the quantity thereof is appropriately changed according to the specification (use) of the semiconductor device.

-The heat dissipation metal on the back side of the semiconductor module may be, for example, aluminum other than copper.
-The cooler may be made of, for example, ceramics in addition to aluminum. In this case, for example, a copper metal plate may be disposed between the ceramic cooler and the copper heat dissipation metal.

-It can be applied when the cooler and the metal on the back side of the semiconductor module are different materials.
The material of the metal plate is not limited as long as it is closer to the linear expansion coefficient of the heat dissipating metal than the linear expansion coefficient of the cooler.

-As shown in Drawing 7 (b), although the upper surface of metal plates 40-42 and the upper surface of heat sink 20 were flush, they may not be flush.
In addition, the material, shape, and the like of the component parts in the above-described embodiment are appropriately changed according to the specifications (uses) of the semiconductor device. In addition, the entire configuration of the semiconductor device in the above-described embodiment is appropriately changed according to the specification (use) of the semiconductor device.

  DESCRIPTION OF SYMBOLS 10 ... Semiconductor device, 20 ... Heat sink, 30 ... Semiconductor module, 31 ... Semiconductor module, 32 ... Semiconductor module, 37 ... Radiation metal, 40, 41, 42 ... Metal plate, 45 ... Recessed part, 50, 51, 52 ... Radiation grease , 60 ... leaf spring, 70 ... spring retainer bracket, R1 ... reservoir chamber.

Claims (5)

A cooler,
A semiconductor module having a heat dissipating metal on the back surface;
A metal plate that is joined to the arrangement region of the semiconductor module in the cooler, and closer to the linear expansion coefficient of the heat dissipation metal than the linear expansion coefficient of the cooler,
A pressing means for pressing the heat dissipation metal side of the semiconductor module to the metal plate of the cooler via heat dissipation grease;
A semiconductor device comprising:   The semiconductor device according to claim 1, wherein the metal plate has a concave portion that opens toward the semiconductor module on a surface facing the semiconductor module.   3. The semiconductor device according to claim 1, further comprising a heat dissipation grease accumulation chamber between a side surface of the metal plate and the cooler around the metal plate.   The semiconductor device according to claim 2, wherein a plurality of the recesses are provided in the metal plate.   The semiconductor device according to claim 2, wherein the recess has an annular shape.