JP2008311550A - Power semiconductor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power semiconductor module that prevents cracking on a bolting fixture portion of a base plate formed of a material with a low breakdown resistance value. <P>SOLUTION: The power semiconductor module comprises a finned base plate 2 where a power semiconductor element 19 is mounted at a top side and a plurality of heat radiating fins 8 are formed at a bottom side, a stiffening plate 4 arranged at the top side of the finned base plate 2, a cooling jacket 5 that is fixed at the bottom side of the finned base plate 2 to form a cooling medium flow passage, a first buffering member 10 arranged between the stiffening plate 4 and the finned base plate 2, and a second buffering member 10' arranged between the finned base plate 2 and the cooling jacket 5. The linear expansion coefficient of the cooling jacket 5 and the stiffening plate 4 is larger than that of the finned base plate 2, and the first and second buffering members are arranged inside and outside a clamping fixture. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, an insulating substrate including a power semiconductor element such as IGBT (Insulated Gate Bipolar Transistor) made of silicon (Si) or silicon carbide (SiC) or MOS FET is disposed on a base plate, and the base plate is cooled by a cooling medium. The present invention relates to a power semiconductor module.

Usually, in a hybrid vehicle or an electric vehicle, a power converter (hereinafter referred to as an inverter) is used to drive a large-capacity travel motor. The inverter uses a power semiconductor element such as an IGBT to convert DC power to three-phase AC power to drive a traveling motor and to regenerate energy by converting three-phase AC power to DC power. It has become.
A power semiconductor module composed of an IGBT or the like generates a very large amount of heat because it controls a large current to drive a traveling motor. On the other hand, miniaturization is required for the power semiconductor module mounted on the hybrid vehicle or the electric vehicle. Therefore, the cooling of the power semiconductor module generally employs a water cooling structure with high cooling efficiency.

FIG. 1 shows an example of a so-called indirect cooling type power semiconductor module in which a plurality of power semiconductor elements are mounted on a mounting surface of a cooling jacket in which a cooling medium is circulated to dissipate heat.
As shown in FIG. 1A, the element housing 20 that houses a plurality of power semiconductor elements is fixed on the mounting surface 5 a of the cooling jacket 5 with bolts 7. Silicon grease for reducing thermal resistance is applied to the contact surface between the base plate 22 and the cooling jacket 5 of the element housing 20 to enhance thermal conductivity.
The cooling medium introduced from the water supply nipple 14 is discharged from the drainage nipple 15 after flowing through the flow path inside the cooling jacket 5. Inside the cooling jacket 5, heat radiating fins 8 arranged at a pitch of 1 to 2 mm are integrally formed to enhance the heat radiating performance.

FIG. 1B is a cross-sectional view at YY (FIG. 1A) of the power semiconductor module 1 in which the element housing 20 and the cooling jacket 5 are combined.
The element housing 20 is configured by solder-bonding the insulating substrate 3 on which the power semiconductor element 19 is mounted to the surface of the base plate 22, and further attaching a housing 23 surrounding the element to the base plate 22.
The insulating substrate 3 has an insulating layer 30 made of an insulating material such as insulating ceramics (for example, aluminum nitride or silicon nitride) having good thermal conductivity and a linear expansion coefficient close to Si, and copper or copper provided on both surfaces thereof. It is composed of metal layers 31 and 31 'made of aluminum or the like. The power semiconductor element 19 is bonded to the upper metal layer 31 via the solder layer S. Further, the lower metal layer 31 ′ is joined to the surface of the base plate 22 via the solder layer S.

The thickness of the metal layers 31, 31 ′ is determined in consideration of the amount of current flowing through the circuit pattern. Further, the thickness of the base plate 22 is usually set to 3 to 4 mm in order to enhance the function as a heat diffusion plate, and the heat capacity is increased.
An external terminal 21 is integrally formed in the housing 23, and the power semiconductor element 19 or the metal layer 31 and the external terminal 21 are bonded and connected by an aluminum wire.

  As described above, the indirect cooling type power semiconductor module 1 shown in FIGS. 1A and 1B has silicon grease on its contact surface in order to reduce the thermal resistance between the element housing 20 and the cooling jacket 5. Is applied. However, the thermal conductivity of silicon grease that is normally used is about 1 W / m · K, which is two orders of magnitude smaller than the thermal conductivity of the base plate 22 and the insulating substrate 3, and the heat generated by the power semiconductor element 19 is reduced to the cooling jacket 5. It was difficult to obtain satisfactory heat dissipation performance due to insufficient conduction to the side.

  Therefore, in Patent Document 1, for example, as shown in FIG. 2, the radiating fins 8 are integrally formed on the back side of the flat base plate to form the finned base plate 2, and the radiating fins 8 are directly cooled with a cooling medium. The direct cooling type power semiconductor module 1 has been proposed.

  As described above, the power semiconductor element 19 generates a very large amount of heat. Therefore, in general, in the direct cooling type power semiconductor module 1 as shown in FIG. 2, the insulating substrate 3 and the finned base plate 2 are made of a material having a linear expansion coefficient close to that of the power semiconductor element 19. Cracks of the solder layer S located between the element 19 and the insulating substrate 3 and between the insulating substrate 3 and the finned base plate 2 are prevented.

  For example, since the linear expansion coefficient of silicon which is a constituent material of the power semiconductor element 19 is about 3 ppm / ° C., an aluminum nitride substrate or a silicon nitride substrate having a linear expansion coefficient of 4 to 5 ppm / ° C. is used as the insulating substrate 3. .

The finned base plate 2 is made of an Al—SiC (aluminum-silicon carbide) composite plate having a linear expansion coefficient of 4 to 8 ppm / ° C. in consideration of ease of processing.
According to the fin-equipped base plate 2 using this Al—SiC composite plate, cracks of the solder layer S described above can be prevented, and the complex-shaped heat radiation fin 8 can be easily formed by molding. it can.
JP 2004-235175 A

  However, the finned base plate 2 using the Al—SiC composite plate has a defect that the fracture toughness value is low due to the characteristics of SiC as the main component, that is, high hardness and low viscosity. For this reason, in the conventional power semiconductor module 1 in which the finned base plate 2 is formed of an Al—SiC composite plate, the ambient temperature of the power semiconductor module 1 increases / decreases with the finned base plate 2 and the cooling jacket 5 fixed with bolts. As a result, the base plate 2 with fins may be cracked by the stress generated in the bolt fixing portion.

This will be specifically described with reference to FIG.
FIG. 3 is an enlarged cross-sectional view of a bolt fixing portion in which the finned base plate 2 shown in FIG. 2 and the housing 23 arranged on the surface side thereof are fixed to the cooling jacket 5 with bolts 7. In FIG. 3, an O-ring 24 is fitted into a groove formed in the aluminum cooling jacket 5, and the finned base plate 2 of the Al—SiC composite plate and the housing 23 are bolted to the cooling jacket 5 on the outside thereof. . The finned base plate 2 is pressed against the cooling jacket 5 side by crushing the O-ring 24 by a pressing force P fixed to the bolt. Therefore, the finned base plate 2 is in a state where a slight gap is opened between the fin 7 and the cooling jacket 5 on the inner side of the bolt 7, and is closely attached to the cooling jacket 5 on the outer side of the bolt 7 where the O-ring 24 is not present. It becomes a state.

  The aluminum cooling jacket 5 (about 24 ppm / ° C.) has a larger amount of thermal expansion / contraction than the finned base plate 2 (4-8 ppm / ° C.) having a small linear expansion coefficient. Therefore, in the configuration shown in FIG. 3, when a temperature cycle test of −40 to + 85 ° C. assuming an in-vehicle environment is performed, the O-ring 24 does not exist, and the finned base plate 2 and the cooling jacket 5 are in direct contact with each other. On the outside of the bolt 7, the frictional force W is generated at the interface due to the difference in linear expansion coefficient between the finned base plate 2 and the cooling jacket 5, whereby a tensile force E is applied outward from the bolt fixing portion of the finned baseplate 2. Will work. If this tensile force E exceeds the fracture toughness value of the Al-SiC composite plate, cracks from the approximate center of the bolt fixing portion on the surface side of the finned base plate 2 toward the back side of the finned base plate 2 in the direction of the tensile force E 32 is generated. If the crack 32 occurs, the liquid tightness between the finned base plate 2 and the cooling jacket 5 via the O-ring 24 is impaired, and the cooling medium flowing between the heat radiation fins 8 may leak out.

  Therefore, the present invention, for example, when a base plate formed of a material having a low fracture toughness value such as an Al-SiC composite plate and a cooling jacket having a different linear expansion coefficient are bolted, It is an object of the present invention to provide a power semiconductor module in which cracks are not generated in the base plate in the portion and the liquid tightness of the cooling medium flow path is ensured.

  In order to solve the above problems, a power semiconductor module according to the present invention includes: i) a base plate on which a power semiconductor element to be cooled is mounted on the surface side; ii) a reinforcing plate disposed on the surface side of the base plate; iii) a cooling jacket fixed to the back side of the base plate with a plurality of fastening fixtures penetrating the reinforcing plate and the base plate, and forming a cooling medium flow path between the base plate and iv) the reinforcing plate A first buffer member disposed between the base plate and v) a second buffer member disposed between the base plate and the cooling jacket, wherein the linear expansion coefficient of the cooling jacket and the reinforcing plate is The linear expansion coefficient of the base plate is larger, and the first buffer member and the second buffer member are at least the tightening member. It is arranged inside and outside the attached fastener.

  Preferably, the base plate includes a plurality of radiating fins formed in a region on the back surface opposite to the mounting region of the power semiconductor element, and the cooling medium flow path is formed so as to surround the radiating fins. .

  Preferably, the first buffer member and the second buffer member are respectively selected from an O-ring, a metal gasket, and an adhesive resin layer.

  Preferably, the reinforcing plate is integrally formed with a housing surrounding the power semiconductor element.

  More preferably, the reinforcing plate and / or the cooling jacket is made of aluminum or stainless steel.

  Therefore, according to the power semiconductor module of the present invention, for example, a base plate formed of a material having a low fracture toughness value such as an Al-SiC composite plate and a cooling jacket having a different linear expansion coefficient are bolted. Even in this case, the base plate does not crack at the bolt fixing portion, and the liquid tightness of the cooling medium flow path can be ensured.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS.

FIG. 4A shows a 600 V / 600 A class direct cooling power semiconductor module 1 according to the first embodiment. The power semiconductor module 1 mainly includes a finned base plate 2, a cooling jacket 5, and a reinforcing plate 4 bolted to the cooling jacket 5 together with the finned base plate 2. Three insulating substrates 3 are soldered to the surface of the base plate 2 with fins, and a plurality of power semiconductor elements are mounted on the surface of the insulating substrate 3.
The insulating substrates 3 in the present embodiment are the same made of aluminum nitride, and constitute the upper and lower arms of the U-phase inverter, the upper and lower arms of the V-phase inverter, and the upper and lower arms of the W-phase inverter, respectively.

In this embodiment, the insulating substrate 3 has an outer dimension of 4.7 cm × 6.0 cm, and an IGBT element having a chip size of 10 mm × 16 mm and an FWD element having a chip size of 7 mm × 10 mm each have a melting point of 240 ° C. or more. Bonded with lead-free solder. The solder thickness is about 0.1 mm. The voltage / current rating of each element is 600V / 300A, and the module is rated 600V / 600A by connecting two elements in parallel.
The insulating substrate 3 and the finned base plate 2 are joined with lead-free solder having a melting point of about 200 ° C. The solder thickness is about 0.1 mm. For simplification, in FIG. 4A, the housing and the aluminum wires for connection that cover the surface side of the finned base plate 2 are omitted.

  In the present embodiment, the finned base plate 2 is provided with a total of eight φ7 mm through holes 6 into which the bolts 7 are inserted. The outer dimensions are 10 cm × 21 cm, and the thickness is about 11 mm. The finned base plate 2 is an Al—SiC composite plate, and each surface thereof is plated with Ni.

As shown in FIG. 4A, in the power semiconductor module 1 according to the first embodiment, the reinforcing plate 4 having a thickness of about 3 mm is overlapped on the surface side of the finned base plate 2 so as to surround the three insulating substrates 3. Be placed. The outer dimension of the reinforcing plate 4 is 10 cm × 21 cm, which is the same as that of the finned base plate 2, and an inner portion of 6 cm × 19 cm is removed so as not to interfere with the insulating substrate 3. The reinforcing plate 4 is provided with a total of eight through-holes 6 having a diameter of 7 mm at the same position as the finned base plate 2 so as to be bolted to the cooling jacket 5 together with the finned base plate 2.
The reinforcing plate 4 can be integrally formed with a housing (not shown) surrounding the power semiconductor element.

On the back surface side of the finned base plate 2 according to the first embodiment shown in FIG. In the present embodiment, 17 radiating fins 8 are formed in parallel with the longitudinal direction (cooling medium flow direction) of the finned base plate 2 and have a protruding amount of 8 mm and a width of 1.5 mm, respectively. Moreover, the pitch of the radiation fins 8 is 3 mm, and the flow path width between the radiation fins 8 is 1.5 mm. The radiating fin 8 has a long life coolant (LLC) 50 vol. % Cooled.
In addition, the said radiation fin shape, arrangement | positioning, and a cooling medium are examples, and can be changed suitably.

  FIG. 5 is a cross-sectional view showing a state where the reinforcing plate 4 and the finned base plate 2 are attached to the cooling jacket 5 of the power semiconductor module 1 according to the first embodiment. In FIG. 5A showing the cross-sectional structure of the power semiconductor module 1 at XX in FIG. 4A, the finned base plate 2 is disposed on the cooling jacket 5, and the reinforcing plate 4 is further stacked thereon. Has been placed. The reinforcing plate 4 and the finned base plate 2 are fixed to the cooling jacket 5 with a fastening fixture (in this embodiment, a bolt 7 as an example) that penetrates through the through-holes 6 formed therein and is screwed into the bolt holes 6 ′. Is done. The bolt 7 used is an M6 bolt, and the tightening torque is about 4 N · m.

In this embodiment, grooves 9 having a width of 2.4 mm and a depth of 1.4 mm are formed on the outer side and the inner side of the through hole 6 of the reinforcing plate 4, respectively, and a first buffer member (an example in this embodiment) As an O-ring 10). Similarly, a groove 9 ′ having a width of 2.4 mm and a depth of 1.4 mm is formed on the outer side and the inner side of the bolt hole 6 ′ of the cooling jacket 5, respectively, and a second buffer member (in this embodiment, in this embodiment). As an example, an O-ring 10 ′) is arranged. The O-ring 10, 10 ′ has a wire diameter of φ1.9 mm. The dimensions of the grooves 9 and 9 'to be formed are determined in consideration of the material composition and elasticity of the O-rings 10 and 10'.
The terms “inside” and “outside” mean a portion corresponding to the region surrounded by the through hole 6 among the regions around the through hole 6 arranged around the finned base plate 2. The “outside” means a portion corresponding to a region that is not surrounded by the through hole 6 (region close to the end of the finned base plate 2).

FIG. 5B is an enlarged cross-sectional view of the bolt fixing portion of the power semiconductor module 1 shown in FIG. In this embodiment, the reinforcing plate 4 and the cooling jacket 5 are made of aluminum having a linear expansion coefficient of 24 ppm / ° C., and the finned base plate 2 is made of an Al—SiC composite plate having a linear expansion coefficient of 3.5 ppm / ° C. In addition, as the material of the reinforcing plate 4 and the cooling jacket 5, stainless steel (linear expansion coefficient: 10 to 17 ppm / ° C.) can be selected. In particular, the reinforcing plate 4 having a linear expansion coefficient of 10 ppm / ° C. or more and When the cooling jacket 5 and the finned base plate 2 made of an Al—SiC composite plate are combined, the effect of the present invention becomes remarkable.
That is, in the power semiconductor module 1 according to the present invention, the finned base plate 2 is disposed between the reinforcing plate 4 and the cooling jacket 5 having a relatively high linear expansion coefficient.

  Generally, in-vehicle power semiconductor modules are required to respond to a temperature change of −40 to + 85 ° C. (ΔT = 125 ° C.). The finned base plate 2, the reinforcing plate 4, and the cooling jacket 5 are Thermal expansion / contraction according to each linear expansion coefficient. As is clear from the arrows schematically showing the degree of thermal expansion / contraction of each component in FIG. 5B, the finned base plate 2, the reinforcing plate 4, and the cooling jacket 5 have the same temperature change. The amount of dimensional change with respect to is different.

  The power semiconductor module 1 according to the first embodiment cracks in the finned base plate 2 even if the finned base plate 2, the reinforcing plate 4, and the cooling jacket 5 are thermally expanded / shrinked in accordance with the temperature change of −40 to + 85 ° C. Will not occur. That is, according to the power semiconductor module 1 according to the first embodiment, it is possible to ensure the reliability under the environmental temperature condition required for the in-vehicle power semiconductor module.

  This is because the first buffer member 10 is disposed outside and inside the through hole 6 of the reinforcing plate 4 and the second buffer member 10 ′ is disposed outside and inside the bolt hole 6 ′ of the cooling jacket 5. Since the finned base plate 2 is prevented from coming into direct contact with the cooling jacket 5 and the reinforcing plate 4 having different linear expansion coefficients, the bolt fixing pressing force P is applied evenly to the finned base plate 2. It is.

FIG. 6 shows a power semiconductor module according to the second embodiment. This power semiconductor module 1 is obtained by reducing the number of O-rings 10 and 10 'used in the first embodiment to one each. As shown in FIG. 6, the O-rings 10 and 10 ′ according to the present embodiment surround the through hole 6 of the reinforcing plate 4 and the bolt hole 6 ′ of the cooling jacket 5 in a substantially circular shape, and between adjacent bolt fixing portions. Are arranged in a groove 9 formed in the reinforcing plate 4 and a groove 9 ′ formed in the cooling jacket 5.
Also in the power semiconductor module 1 according to the second embodiment, the same effects as those according to the first embodiment can be obtained, and the reliability under the environmental temperature condition required for the power semiconductor module for vehicle use can be ensured. .

FIG. 7 shows a power semiconductor module according to the third embodiment. In this power semiconductor module 1, the O-ring 10 (first buffer member) disposed between the circular thin plate-shaped reinforcing plate 4 and the finned base plate 2 and the reinforcing plate 4 are formed into a circular thin plate shape for each bolt fixing portion. It is divided. The O-ring 10 on the reinforcing plate 4 side shown in FIG. 7 does not have a shape in which the O-rings 10 between adjacent bolt fixing portions are connected as in the first embodiment. This is because there is no fear that the cooling medium leaks between the reinforcing plate 4 and the finned base plate 2.
In the power semiconductor module 1 according to the third embodiment, the same effects as those according to the first and second embodiments can be obtained, and the amount of members used for the O-rings 10 and 10 ′ can be reduced.

  FIG. 8 shows a power semiconductor module according to the fourth embodiment. This power semiconductor module 1 uses a metal gasket 11 as a second buffer member between the finned base plate 2 and the cooling jacket 5. The metal gasket 11 is obtained by coating an elastic resin on a thin metal plate partially formed with a convex portion 11 ′. In the present embodiment, one linear convex portion 11 ′ having a step of about 0.2 mm is formed inside and outside the screw fixing portion. The convex portion 11 ′ may have other shapes. For example, like the O-ring 10 according to the second embodiment (FIG. 6), the bolt fixing portion is surrounded in a substantially circular shape, and the adjacent bolt fixing portions are mutually connected. It can be made into a connected shape.

FIG. 9 shows a power semiconductor module according to the fifth embodiment. This power semiconductor module 1 uses an adhesive resin layer 12 made of an elastic silicon adhesive resin as a first buffer member between the reinforcing plate 4 and the finned base plate 2. The silicon adhesive resin is applied on the finned base plate 2 so as to surround the bolt fixing portion, and the reinforcing plate 4 is bonded thereto. By doing so, the silicon adhesive resin is thinly extended over a wide range, and the space between the reinforcing plate 4 and the finned base plate 2 can be filled without a gap. Thereafter, heat treatment is performed on the silicon adhesive resin to form the adhesive resin layer 12 that is cured while having a certain elasticity.
In the power semiconductor module 1 according to the fifth embodiment, there is no need to prepare different buffer members (O-rings or the like) for each shape and size of the finned base plate 2, and the initial cost for manufacturing the power semiconductor module 1 is reduced. Can do.
In addition, the same effect can be acquired even if it uses an epoxy-type low-elasticity resin and a urethane resin for the adhesive resin layer 12 instead of a silicone adhesive resin.

FIG. 10 shows a power semiconductor module according to Example 6 using a finned base plate 2 having a ring shape and a flat plate shape. The power semiconductor module 1 can be manufactured integrally with a traveling motor for a hybrid vehicle or an electric vehicle. For example, by using the end wall of the motor housing 13 instead of a cooling jacket, the flow of the cooling medium can be improved. A path can be formed.
The motor housing 13 is provided with a water supply nipple 14 and a drainage nipple 15. The cooling medium introduced from the water supply nipple 14 is distributed to the heat radiating fins 8 by the introduction liquid reservoirs 14 ′, and flows between the heat radiating fins 8, and then is collected and discharged to the drainage nipple 15 by the discharge liquid reservoir 15 ′. .

  According to the power semiconductor module 1 according to the sixth embodiment, it is possible to reduce the size and weight and reduce the cost, and to cool the inverter and the traveling motor at the same time. In addition, by arranging the inverter and the distance between the driving motor that is the driving target to be close to each other, the circuit connection can be shortened, and the wiring loss can be reduced. Further, the hollow portion of the power semiconductor module 1 can be used as a region through which the motor shaft is passed or where a power supply line to the traveling motor is arranged.

The power semiconductor module 1 shown in FIG. 10 includes a first buffer member (not shown) between the reinforcing plate 4 and the finned base plate 2, and a second buffer member between the finned base plate 2 and the motor housing 13. The various buffer members according to the first to fifth embodiments and combinations thereof can be applied to (not shown).
Therefore, also in the power semiconductor module 1 according to the sixth embodiment, the same effects as those according to the other embodiments can be obtained, and the reliability in the environmental temperature condition required for the in-vehicle power semiconductor module is ensured. can do.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to the said structure, It is obvious that those skilled in the art can come up with various modifications.

For example, the insulating substrate used in each embodiment can be replaced with an insulating resin layer.
In FIG. 11, the insulating resin layer 16 is disposed in close contact with the surface side of the finned base plate 2, and the wiring conductor plate 17 is disposed on the insulating resin layer 16. The wiring conductor plate 17 is formed by bonding a copper plate on the insulating resin layer 16 and removing (patterning) unnecessary portions other than the conductor pattern from the copper plate by an etching process. In addition, the wiring conductor plate 17 and the finned base plate 2 have insulation performance secured by the insulating resin layer 16 disposed therebetween and the patterned creepage distance.

The power semiconductor element 19 is soldered to the heat diffusion plate 18, and the heat diffusion plate 18 is soldered to the wiring conductor plate 17. The heat diffusion plate 18 is made of a material having excellent thermal conductivity and heat capacity (for example, copper), and the heat generated by the power semiconductor element 19 is rapidly diffused in the in-plane direction and radiated by the finned base plate 2. . As a result, it is possible to suppress a transient temperature rise due to sudden heat generation of the power semiconductor element 19.
When it is desired to improve environmental resistance such as heat cycle performance, the material of the heat diffusion plate 18 may be replaced with another material having a low linear expansion coefficient (for example, a copper-molybdenum composite material). Further, when the amount of heat generated by the power semiconductor element 19 is not so large, the heat diffusion plate 18 may be omitted and the power semiconductor element 19 and the wiring conductor plate 17 may be directly joined.
According to the above configuration, since it is not necessary to use an expensive insulating substrate such as an aluminum nitride substrate, the cost can be reduced.

Further, the power semiconductor module according to the present invention includes various first and fifth embodiments according to the first to fifth embodiments as a first buffer member between the reinforcing plate and the finned base plate and a second buffer member between the finned base plate and the cooling jacket. These buffer members can be applied in appropriate combination.
For example, the adhesive resin layer 12 (see Example 5 and FIG. 9) may be used as the first buffer member, and the O-ring 10 ′ (see Example 2 and FIG. 6) may be used as the second buffer member.

  In each embodiment, the direct cooling type power semiconductor module using the fin-equipped base plate in which the radiating fin is integrally formed on the base plate has been described. However, the present invention directly applies the flat plate base plate in which the radiating fin is not integrally formed. The present invention can also be applied to a power semiconductor module having a cooling structure.

It is a figure which shows an example of an indirect cooling type power semiconductor module, (A) is a perspective view, (B) is sectional drawing. It is sectional drawing which shows the conventional direct cooling type power semiconductor module. It is an expanded sectional view of the bolt fixing | fixed part of the conventional direct cooling type power semiconductor module. (A) is a perspective view of the power semiconductor module which concerns on Example 1, (B) is a perspective view which shows the back surface side of the base plate with a fin used with the power semiconductor module which concerns on Example 1. FIG. 1 is a power semiconductor module according to a first embodiment, where (A) is an overall cross-sectional view and (B) is an enlarged cross-sectional view of a bolt fixing portion. 6 is a perspective view of a power semiconductor module according to Embodiment 2. FIG. 6 is a perspective view of a power semiconductor module according to Embodiment 3. FIG. FIG. 6 is a perspective view of a power semiconductor module according to a fourth embodiment. 10 is a perspective view of a power semiconductor module according to Embodiment 5. FIG. 10 is a perspective view of a power semiconductor module according to Embodiment 6. FIG. It is sectional drawing which shows the aspect of mounting of the power semiconductor element applicable to each Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power semiconductor module 2 Base plate with fin 3 Insulation board 4 Reinforcement board 5 Cooling jacket 6 Through hole 6 'Bolt hole 7 Bolt 8 Radiation fin 9, 9' Groove 10 1st buffer member (O-ring)
10 'Second buffer member (O-ring)
DESCRIPTION OF SYMBOLS 11 Metal gasket 11 'Convex part 12 Adhesive resin layer 13 Motor housing 14 Water supply nipple 14' Introducing liquid reservoir 15 Drain nipple 15 'Derived liquid reservoir 16 Insulating resin layer 17 Wiring conductor board 18 Thermal diffusion board 19 Power semiconductor element 20 Element container 21 External terminal 22 Base plate 23 Housing 24 O-ring 30 Insulating layer 31 Metal layer 31 ′ Metal layer 32 Crack S Solder layer

Claims (5)

i) a base plate on which power semiconductor elements to be cooled are mounted on the surface side;
ii) a reinforcing plate disposed on the surface side of the base plate;
iii) a cooling jacket fixed to the back side of the base plate with a plurality of fastening fixtures penetrating the reinforcing plate and the base plate, and forming a cooling medium flow path between the base plate;
iv) a first buffer member disposed between the reinforcing plate and the base plate;
v) a second cushioning member disposed between the base plate and the cooling jacket,
The linear expansion coefficient of the cooling jacket and the reinforcing plate is larger than the linear expansion coefficient of the base plate, and the first buffer member and the second buffer member are disposed at least inside and outside of the fastening fixture. A featured power semiconductor module.   The base plate includes a plurality of radiating fins formed in a region on the back surface opposite to the mounting region of the power semiconductor element, and the cooling medium flow path is formed so as to surround the radiating fins. The power semiconductor module according to claim 1.   2. The power semiconductor module according to claim 1, wherein each of the first buffer member and the second buffer member is selected from an O-ring, a metal gasket, and an adhesive resin layer.   The power semiconductor module according to claim 1, wherein the reinforcing plate is formed integrally with a housing surrounding the power semiconductor element.   The power semiconductor module according to claim 1, wherein the reinforcing plate and / or the cooling jacket is made of aluminum or stainless steel.

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