Power semiconductor device

Abstract

This power semiconductor device is provided with an elastically deformable biasing member that presses a heat dissipation member against a plurality of power modules, and the biasing member has: a pair of pressing parts that come into contact with the heat dissipation member; a plurality of loaded parts which are provided on the outside of the pair of pressing parts and which receive a load by means of a fixing member; and an intermediate section that is provided between the pair of pressing sections and generates a bending stress corresponding to the load, the plurality of power modules being arranged along the direction in which the pair of pressing sections extend. The intermediate portion elastically deforms in a direction away from the heat dissipation member due to the bending stress when the heat dissipation member is pressed by the biasing member.

Description

Technical Field

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

[0002] In recent years, hybrid and electric vehicles have become increasingly popular to reduce environmental impact. However, miniaturization and cost reduction are becoming increasingly important for the components used in these vehicles. In particular, power semiconductor devices in power converters require miniaturization and cost reduction. Furthermore, miniaturization of these high-heat-generating electronic components requires improved cooling performance.

[0003] For example, Patent Document 1 discloses a power semiconductor device having a power module and a cooler provided with a heat transfer member interposed therebetween. A leaf spring is provided on the outside of the power module. By pressurizing the power module, the heat transfer member, and the cooler, miniaturization is achieved and component mountability is improved. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2021-005603 Summary of the Invention Problems to be solved by the invention

[0005] In the leaf spring structure of the power semiconductor device described in Patent Document 1, when a load is applied to the load-bearing portion formed outside the power module, the pressure point is displaced in the horizontal direction, resulting in an inability to efficiently apply pressure in the stacking direction. Specifically, in order to improve cooling performance, the existing structure requires efficient pressure application across a wider heat dissipation surface. In view of this, the present invention aims to provide a highly reliable power semiconductor device that achieves miniaturization, a reduction in the number of components, and improved heat dissipation, while also enabling efficient pressure application in the stacking direction. Technical means to solve the problem

[0006] The power semiconductor device comprises: a plurality of power modules, which are formed by mold-sealing semiconductor elements and conductor plates joined to the semiconductor elements; a heat dissipation component, which contacts at least one surface of the power module via a heat-conducting component; and a force-applying component, which presses the heat dissipation component toward the power module and is elastically deformable, the force-applying component comprising: a pair of pressurizing portions, which abut against the heat dissipation component; a plurality of load-bearing portions, which are arranged on the outside of the pair of pressurizing portions and bear the load through a fixing component; and an intermediate portion, which is arranged between the pair of pressurizing portions and generates a bending stress corresponding to the load, the plurality of power modules are arranged along the extension direction of the pair of pressurizing portions, and the intermediate portion is elastically deformed in a direction away from the heat dissipation component due to the bending stress when the force-applying member presses the heat dissipation component. Effects of the Invention

[0007] According to the present invention, it is possible to provide a highly reliable power semiconductor device that can achieve miniaturization, a reduction in the number of components, and improved heat dissipation, and can efficiently apply pressure in the stacking direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A cross-sectional view showing a semiconductor module of a power semiconductor device. Figure 2 It is an overall perspective view of a power semiconductor device according to a first embodiment of the present invention. Figure 3 for Figure 2 Cross-sectional view of a power semiconductor device. Figure 4 This is an explanatory diagram showing problems with the structure of a conventional power semiconductor device. Figure 5 It is an explanatory diagram showing the structure of a power semiconductor device to which the present invention is applied. Figure 6 It is a plan view showing a power semiconductor device according to the first embodiment of the present invention. Figure 7 for Figure 6 AA cross-section diagram. Figure 8 for Figure 6 BB cross-section diagram. Figure 9 This is a plan view illustrating a biasing member according to a first embodiment of the present invention. Figure 10 This is a cross-sectional view of the power semiconductor device viewed from the direction in which the power modules are arranged. Figure 11 This is a plan view illustrating a loaded portion of a biasing member according to the first embodiment of the present invention. Figure 12It is a cross-sectional view of a power semiconductor device according to a second embodiment of the present invention. Figure 13 It is a cross-sectional view of a power semiconductor device according to a third embodiment of the present invention. Figure 14 It is a cross-sectional view of a power semiconductor device according to a fourth embodiment of the present invention. Figure 15 It is a plan view of a biasing member according to a fifth embodiment of the present invention. Figure 16 for Figure 15 CC cross-section diagram. Figure 17 It is a cross-sectional view of a biasing member according to a sixth embodiment of the present invention. Figure 18 It is a cross-sectional view of a biasing member according to a seventh embodiment of the present invention. Figure 19 It is a plan view of a biasing member according to an eighth embodiment of the present invention. Figure 20 It is a cross-sectional view of a power semiconductor device according to a ninth embodiment of the present invention. DETAILED DESCRIPTION

[0009] The following describes embodiments of the present invention with reference to the accompanying drawings. The following description and drawings are examples for illustrating the present invention and have been omitted or simplified as appropriate for clarity of description. The present invention may also be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0010] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0011] (First embodiment and overall structure of the present invention) ( Figure 1 ) The power semiconductor device according to an embodiment of the present invention includes multiple semiconductor modules 100 (power modules 100) each including a power semiconductor element 1, a first conductor 3 serving as a conductive plate bonded to the power semiconductor element 1, and a second conductor 3b. The power semiconductor element 1, the first conductor 3, and the second conductor 3b are bonded to each other via a bonding material 2. The surface electrodes of the power semiconductor element 1 are connected to the second conductor 3b via the bonding material 2. The first conductor 3 and the second conductor 3b are made of, for example, copper, a copper alloy, aluminum, or an aluminum alloy. The bonding material 2 is, for example, solder or a sintered material.

[0012] The first conductor 3 is connected to the insulating layer 4, a thermally conductive member, on the surface opposite to the surface connected to the power semiconductor element 1. Similarly, the second conductor 3b is connected to the insulating layer 4, a thermally conductive member, on the surface opposite to the surface connected to the power semiconductor element 1. The insulating layer 4 conducts heat generated by the power semiconductor element 1 to the heat dissipation members 7 and 7b described later. It is formed from a material with high thermal conductivity and a high dielectric strength. Examples of the insulating layer 4 include ceramics such as alumina (aluminum oxide), aluminum nitride, or silicon nitride, or insulating sheets or adhesives containing fine powders of these.

[0013] Semiconductor module 100 is molded and encapsulated with sealing resin 10 so that insulating layer 4 is exposed on the surface. The surface of insulating layer 4 exposed from sealing resin 10 serves as the heat dissipation surface of semiconductor module 100. Semiconductor module 100 includes external terminals 3c for electrically connecting power semiconductor element 1 to external wiring, etc. External terminals 3c protrude from sealing resin 10.

[0014] ( Figure 2 ) The semiconductor module 100 has a heat dissipation member 7 (7b) on at least one surface thereof in contact with the insulating layer 4 via the insulating layer 4. Figure 2 , the diagram shows a situation in which the first heat dissipating member 7 and the second heat dissipating member 7b are in contact with the semiconductor module 100, sandwiching the semiconductor module 100 from both sides. The semiconductor module 100 faces the fixing flange 8 with the first heat dissipating member 7 interposed therebetween. Furthermore, the semiconductor module 100 faces the spring plate member 9 with the second heat dissipating member 7b interposed therebetween. The spring plate member 9 is an elastically deformable biasing member that presses the heat dissipating member 7b toward the semiconductor module 100. Furthermore, the present invention is not limited to the illustrated semiconductor module 100 with double-sided cooling; it can also be applied to semiconductor modules 100 with single-sided cooling.

[0015] The spring plate member 9 has a pair of pressurizing portions 9a and 9b that abut the heat dissipation member 7b. The pressurizing portions 9a and 9b are generated by the spring plate member 9 pressing the heat dissipation member 7b. First fixing members 13 are inserted into holes formed at multiple ends of the spring plate member 9. The fixing flange 8, connected to each second fixing member 12, serves as a support member when the spring plate member 9 is fixed. The first fixing member 13 is connected to the fixing flange 8 by inserting the second fixing member 12 corresponding to each hole in the spring plate member 9. As a result, the spring plate member 9 receives a load at each position where the fixing member 13 is inserted, and the spring plate member 9 presses the heat dissipation member 7b accordingly.

[0016] ( Figure 3 ) The insulating layer 4 contacts the thermally conductive layer 5 on the surface opposite to the surface in contact with the first conductor 3 and the second conductor 2. The thermally conductive layer 5 contacts the heat dissipation members 7 and 7b on the surface opposite to the surface in contact with the insulating layer 4. The thermally conductive layer 5 is a heat-conducting member such as thermal grease, a TIM (Thermal Interface Material), or a heat sink. The first and second heat dissipation members 7 and 7b are thermally conductive members, such as Cu, a Cu alloy, a Cu-C, or Cu-CuO composite material, or an Al, an Al alloy, AlSiC, or an Al-C composite material.

[0017] The position of a pair of pressurizing parts 9a, 9b is Figure 3 In the cross section, the spring plate member 9 preferably applies pressure to the heat conductive layer 5 at a position between the center of the heat conductive layer 5 and both ends of the heat conductive layer 5. Thus, when the spring plate member 9 presses the heat dissipation member 7b, a uniform and uniform surface pressure is applied to the heat conductive layer 5. This prevents the semiconductor module 100 and the heat dissipation member 7b from deviating from each other, thereby achieving a power semiconductor device with high heat dissipation performance and reliability.

[0018] The spring plate member 9 has an intermediate portion 9c between the pair of pressing portions 9a and 9b. The spring plate member 9 also has a plurality of loaded portions 11 disposed outside the pair of pressing portions 9a and 9b and loaded by the fixing member 13.

[0019] The pair of pressurizing portions 9a and 9b are formed at positions overlapping the arrangement region of the power semiconductor element 1 in cross section. The pair of pressurizing portions 9a and 9b do not necessarily need to be formed at positions overlapping the arrangement region of the power semiconductor element 1. However, by forming them at positions overlapping the arrangement region of the power semiconductor element 1, the pressing force exerted by the heat dissipating member 7b on the semiconductor module 100 is higher than that exerted by other regions. This improves the heat dissipation performance in the arrangement region of the power semiconductor element 1, where heat dissipation is most required. Consequently, a power semiconductor device with high overall heat dissipation performance can be realized.

[0020] (Comparison between the conventional structure and the structure of the present invention) ( Figure 4 、 Figure 5 ) Figure 4 (a) is a diagram showing a state before the conventional spring plate member 50 presses the heat dissipation member 7b. Figure 4 (b) is a diagram showing a state where the existing spring plate member 50 presses the heat dissipation member 7b. Figure 5 (a) is a diagram showing a state before the spring plate member 9 of the present invention presses the heat dissipation member 7b. Figure 5 (b) is a diagram showing a state where the spring plate member 9 according to the present invention presses the heat dissipation member 7b.

[0021] exist Figure 4 In the conventional structure shown in (a), before the conventional spring plate member 50 presses the heat sink 7b, the pair of conventional pressing portions 50a, 50b are in line contact (point contact in cross section) with the heat sink 7b toward the inner side of the cross section. The conventional pressing portions 50a, 50b are shaped to leave a predetermined space between them and the heat sink 7b, and form an acute angle θ1 from each of the conventional pressing portions 50a, 50b toward the center line 50c.

[0022] In the case of this conventional structure, when a downward force 60 is applied to the existing loaded portions 51a and 51b formed on the outer sides of the existing pressurizing portions 50a and 50b in the left-right direction of the cross section, as shown in FIG. Figure 4 As shown in (b), the positions of the conventional pressurizing portions 50a and 50b are laterally offset toward the centerline 50c in the direction indicated by the arrow. Consequently, the conventional spring plate member 50 has difficulty effectively pressing the heat dissipation member 7b. Furthermore, since the conventional pressurizing portions 50a and 50b are in line contact with the heat dissipation member 7b, the range of the compressive stress applied to the inner side of the heat dissipation member 7b is narrowed.

[0023] In view of this, in the present invention, Figure 5 As shown in FIG. 1 , an intermediate portion 9c is formed between a pair of pressurizing portions 9a and 9b. The intermediate portion 9c has a flat plate shape that contacts the heat dissipating member 7b with its surface. Figure 5 As shown in (a), the spring plate member 9 is parallel to the heat dissipation member 7b in a state of being in contact with the heat dissipation member 7b before being pressed against the heat dissipation member 7b by a load.

[0024] Thus, when a load is applied to the loaded portion 11 protruding from the outer side of the cross section of the spring plate member 9, even if a horizontal force acts between the pressurizing portions 9a and 9b, the intermediate portion 9c can suppress lateral displacement of the pressurizing portions 9a and 9b, thereby preventing damage to the heat dissipating member 7b and improving vibration resistance. Furthermore, by spreading the load applied to the spring plate member 9 to the surface contact portion of the intermediate portion 9c, the load is distributed, which expands the range of compressive stress distribution within the heat dissipating member 7b, generating compressive stress throughout the entire heat dissipating member 7b.

[0025] The bending rigidity of the middle portion 9c between the pair of pressurizing portions 9a and 9b is greater than that of the conventional structure. That is, when the load receiving portion 11 provided outside the pressurizing portions 9a and 9b is loaded, a bending stress corresponding to the load of the fixing member 13 is generated in the middle portion 9c. Figure 5As shown in (b), this bending stress causes intermediate portion 9c to elastically deform in a direction away from the surface of heat sink 7b. This creates a reaction force (restoring force) in the direction opposite to the elastic deformation force acting in the direction away from the surface of heat sink 7b, causing intermediate portion 9c to act in a manner that maximizes surface contact. This allows spring plate member 9 to effectively press heat sink 7 and semiconductor module 100, resulting in a power semiconductor device with high heat dissipation performance and reliability.

[0026] Furthermore, to achieve the effects of the present invention, the angle θ2 formed between the pair of inclined portions 11d formed at both ends of the intermediate portion 9c on the side opposite to the heat dissipating member 7b of the spring plate member 9 and between the intermediate portion 9c and the loaded portion 11 is preferably an obtuse angle. Furthermore, while the pair of pressing portions 9a, 9b, the pair of inclined portions 11d, and the pair of loaded portions 11 of the spring plate member 9 are illustrated above, the shapes of the paired portions are not limited to being identical, as long as the effects are the same.

[0027] ( Figure 6 ) The plurality of semiconductor modules 100 are arranged along the extending direction of the pair of pressing portions 9a, 9b. The pair of pressing portions 9a, 9b are formed at positions overlapping the region where the semiconductor elements 1 are arranged, as viewed from the direction in which the spring plate member 9 presses the heat dissipation member 7b (as viewed from above).

[0028] The spring plate member 9 is formed with a pair of pressurizing portions 9a and 9b that span the three-phase semiconductor module 100. Furthermore, a pair of supported portions 11 are provided on either side of the pair of pressurizing portions 9a and 9b in the vertical direction in a plan view. The supported portions 11 are formed so as to protrude outward at positions away from the location where the semiconductor module 100 is installed. Of the multiple supported portions 11, those located at the four corners are supported portions 11a, and those located outside the four corners are supported portions 11b.

[0029] ( Figure 7 、 Figure 8 ) like Figure 6 The AA cross-section diagram is Figure 7 and Figure 6 The BB cross-section diagram is Figure 8As shown in the cross-sectional view of heat sink 7 (7b), heat sink 7, 7b has a hollow coolant flow path with fins 7e arranged therein. Heat sink 7, 7b has a region where fins 7e are formed and a hollow region 7f where fins 7e are not formed. Coolant flows through hollow region 7f where fins 7e are not formed, but the hollow flow path of heat sink 7, 7b may also be an air-cooling flow path through which air flows, as long as the same effect is achieved.

[0030] If the pressurizing parts 9a and 9b are arranged Figure 8 In the hollow area 7f shown in FIG. 1 , since the cover of the second heat dissipating member 7b is depressed under the pressure of the spring plate member 9, the compressive stress cannot be effectively generated in the heat conducting layer 5. Figure 6 As shown, when viewed from the direction in which the spring plate member 9 presses the heat dissipation member 7b (in a top view), the pair of pressing portions 9a, 9b are preferably provided within the region where the heat dissipation fins 7e are arranged, i.e., within the heat dissipation fin formation region 7d. This effectively generates compressive stress throughout the heat conductive layer 5.

[0031] ( Figure 9 ) The pair of inclined portions 11d are perpendicular to the extending direction of the pressurizing portions 9a and 9b in a cross section (see Figure 5 ) is formed by extending in a direction away from the heat dissipation member 7b with the pair of pressing portions 9a and 9b as a reference. In the spring plate member 9, a plurality of flange portions 11f are provided on the upper and lower outer sides of the intermediate portion 9c and the pressing portions 9a and 9b in the planar direction, extending outward from both ends of the pair of inclined portions 11d.

[0032] The flange portion 11f has a plurality of protrusions 11g that protrude outward from the intermediate portion 11c. When viewed from the direction in which the spring plate member 9 presses the heat dissipation member 11b (as viewed from above), the plurality of protrusions 11g are formed between the plurality of semiconductor modules 100 and in a direction away from the semiconductor modules 100. Furthermore, the flange portion 11f has a pair of connecting portions 11e formed between the inclined portion 11d and the protrusions 11g and extending along the direction in which the pressurizing portions 9a and 9b extend.

[0033] Each of the plurality of protrusions 11g has a hole 11c for fixing the fixing member 13. That is, the loaded portions 11a and 11b are formed on the distal end sides of the plurality of protrusions 11g and have the hole 11c for inserting the fixing member 13.

[0034] ( Figure 10 ) Semiconductor modules 100 are arranged in three phases in a power semiconductor device, but each phase can also be sealed with sealing resin 10. By collectively pressing and securing the three phases of semiconductor modules 100, each phase sealed with sealing resin 10, together from the top and bottom of the cross section, sandwiched between first heat sink member 7 and second heat sink member 7b, heat dissipation from semiconductor modules 100 is achieved. The number of semiconductor modules 100 arranged is merely an example and is not limited to three phases or the number of semiconductor modules arranged.

[0035] ( Figure 11 ) exist Figure 11 ] shows a simplified spring plate member 9. The loaded portions 11a and 11b are formed corresponding to the four corners of the placement region 100b of the semiconductor module 100 for each phase. Thus, the loaded portions 11a and 11b can generate compressive stress on the entire heat transfer layer 5 of the semiconductor module 100.

[0036] Furthermore, among the multiple loaded portions 11a and 11b, the first spring constant of the loaded portions 11a formed at the four corners of the spring plate member 9 is smaller than the second spring constant of the loaded portions 11b formed at locations other than the four corners, and the second spring constant is less than or equal to twice the first spring constant. In other words, the load applied to the loaded portions 11b at locations other than the four corners is greater than the load applied to the loaded portions 11a at the four corners of the spring plate member 9. This reduces the variation in the compressive stress generated in each semiconductor module 100 when the spring plate member 9 presses against the heat sink 7b. Furthermore, the flexural rigidity of the loaded portions 11a and 11b is preferably close to each other.

[0037] (Second embodiment) ( Figure 12 ) While the intermediate portion 9c is shown as being in direct surface contact with the pressing heat sink 7b, an intermediate layer 15 may also be provided between the spring plate member 9 and the heat sink 7b. By using a material with a Young's modulus (longitudinal elastic modulus) lower than that of the heat sink 7b or the spring plate member 9, the intermediate layer 15 can fill the gap even when there are slight irregularities on the surfaces of the heat sink 7b and the intermediate portion 9c of the spring plate member 9, thereby providing the advantage of uniformly pressing the heat sink 7b with the spring plate member 9. Furthermore, using a material with a higher Young's modulus than that of the heat sink 7b for the intermediate layer 15 can prevent slight deformation of the heat sink 7b caused by the pressing portions 9a and 9b.

[0038] In addition, the above description has been made of the case where the entire contact surface of the middle portion 9c of the spring plate member 9 with the heat dissipation member 7b is in contact with the heat dissipation member 7b before the spring plate member 9 is pressed against the heat dissipation member 7b. However, even in the case where a portion of the plane of the middle portion 9c is separated from the heat dissipation member 7b after a load is applied to the spring plate member 9 (see FIG. Figure 5 ), by configuring the material of the intermediate layer 15, the same effect as that of the first embodiment can be obtained.

[0039] (Third embodiment) ( Figure 13 ) The semiconductor module 100 may not be an integrated molded package, but may be composed of a plurality of small molded packages 101. In this case, the same effect can be achieved.

[0040] (Fourth embodiment) ( Figure 14 ) Even in the case where a portion of the heat dissipation member 7b that contacts the spring plate member 9 has a recess 70, the same effect as in the above-described embodiment can be obtained by making the surface on the heat dissipation member 7b side of the intermediate portion 9c between the pressurizing portions 9a and 9b parallel to the upper surface of the heat dissipation member 7b, i.e., the surface on the spring plate member 9 side.

[0041] (Fifth embodiment) ( Figure 15 、 Figure 16 ) In the spring plate member 9, the intermediate portion 9c connecting the pressurizing portions 9a and 9b may also have a plurality of convex ribs 9d on the surface opposite to the surface in contact with the heat dissipating member 7b. Figure 15 As shown in the top view, the rib 9d is formed in a direction perpendicular to the forming direction (extending direction) of the pressurizing portions 9a and 9b. As a result, the bending rigidity of the intermediate portion 9c can be increased compared to the above embodiment, and when the spring plate member 9 is pressed, the central portion of the intermediate portion 9c can be prevented from being separated from the heat dissipation member 7b (see FIG. Figure 5 ), which can press the heat dissipation component 7b in a wider range.

[0042] (Sixth embodiment) ( Figure 17 ) In the above-described intermediate portion 9c, the thickness of the intermediate portion 9c is shown to be the same as that of the load-receiving portion 11 or other regions. However, the intermediate portion 9c may also have a thickness T2 that is thicker than the thickness T1 of the load-receiving portion 11 or other regions. This increases the bending rigidity of the intermediate portion 9c compared to the first embodiment described above, preventing the center portion of the intermediate portion 9c from separating from the heat dissipating member 7b when the spring plate member 9 presses against the heat dissipating member 7b, thereby enabling the application of load over a wider range.

[0043] (Seventh embodiment) ( Figure 18 ) The seventh embodiment achieves the same effects as the sixth embodiment, but differs from the sixth embodiment in the method for manufacturing the thicker intermediate portion 9c. The intermediate portion 9c is formed thicker on the surface opposite the heat dissipation member 7b. The diagram illustrates a case where the intermediate portion 9c, which is thickened by being laminated on the surface opposite the surface in contact with the heat dissipation member 7b, has a thickness T4 that is thicker than the thickness T3 of the load-bearing portion 11 or other regions. This achieves the same effects as the sixth embodiment. Furthermore, the thickened intermediate portion 9c can be laminated with the same material as the spring plate member 9 or with a different material.

[0044] (Eighth Embodiment) ( Figure 19 ) In the above embodiment, the flange portion 11f has a rectangular shape and the base portion and the tip portion of the flange have substantially the same width. However, the flange may also have a tapered shape.

[0045] The width W1 at the base of the tapered flange portion 11f of the loaded portion 11 is greater than the width W2 at the tip of the flange portion 11f. This not only achieves the same effects as the above-described embodiment, but also allows the area of the spring plate member 9 to be further reduced without reducing the surface pressure applied to the heat dissipating member 7b and the semiconductor module 100, thereby achieving weight reduction. Furthermore, by forming the tapered shape so that the extended oblique lines of the flange portion 11f overlap near the center of the semiconductor module 100, surface pressure can be applied to the center of the semiconductor module 100.

[0046] (Ninth embodiment) ( Figure 20 ) The heat dissipation member 7b has a protrusion 70b on the surface that contacts the spring plate member 9. Accordingly, a curved portion 9e is provided in a portion of the center of the intermediate portion 9c of the spring plate member 9, conforming to the shape of the protrusion 70b. The widths W5 and W6 of the cross section of the intermediate portion 9c, excluding the curved portion 9e, are respectively greater than the width W4 of the cross section of the protrusion 9e. This achieves the same effects as the first embodiment.

[0047] In the embodiment described above, an example is shown in which the sealing resin 10 includes the insulating layer 4 in the semiconductor module 100 and seals the portion other than the heat dissipation surface. However, the semiconductor module 100 may also be configured such that the first conductor 3 and the second conductor 3b are sealed without sealing the insulating layers 4 and 4b. Furthermore, the present invention is not limited to the embodiment described above and can be applied in various modifications within the scope of the present invention.

[0048] According to the embodiment of the present invention described above, the following effects are achieved.

[0049] (1) A power semiconductor device includes: a plurality of semiconductor modules 100, each of which is formed by molding a semiconductor element 1 and a conductor plate 3, 3b bonded to the semiconductor element 1; heat dissipation members 7, 7b, which are in contact with at least one surface of the semiconductor module 100 via a heat conducting member 5; and an elastically deformable biasing member 9, which presses the heat dissipation members 7, 7b toward the semiconductor module 100, the biasing member 9 having: a pair of biasing portions 9a, 9b, which abut against the heat dissipation member 7b; a plurality of load-bearing portions 11a, 11b, which are provided outside the pair of biasing portions 9a, 9b and receive a load via a fixing member 13; and an intermediate portion 9c, which is provided between the pair of biasing portions 9a, 9b and generates a bending stress corresponding to the load. The plurality of semiconductor modules 100 are arranged along the extending direction of the pair of biasing portions 9a, 9b. When the biasing member 9 presses the heat dissipation member 7b, the intermediate portion 9c is elastically deformed in a direction away from the heat dissipation member 7b due to the bending stress. Thus, a highly reliable power semiconductor device can be provided, which can achieve miniaturization, a reduction in the number of components, and improved heat dissipation, and can efficiently apply pressure in the stacking direction.

[0050] (2) When viewed from the direction in which the biasing member 9 presses the heat dissipating member 7b, the pair of pressing portions 9a and 9b are formed at positions overlapping with the region where the semiconductor element 1 is disposed. This further improves the heat dissipation performance of the power semiconductor device.

[0051] (3) In a cross section perpendicular to the extension direction, the pair of pressurizing portions 9a and 9b contact the heat dissipation member 7b at positions between the center of the heat conductive member 5 and the ends of the heat conductive member 5. This allows uniform and overall surface pressure to be applied to the heat conductive layer 5, resulting in a power semiconductor device with high heat dissipation performance and reliability.

[0052] (4) Heat dissipation member 7b has a hollow coolant flow path with heat dissipation fins 7e disposed therein. A pair of pressurizing portions 9a and 9b are formed within the region where heat dissipation fins 7e are disposed, as viewed from the direction in which biasing member 9 presses heat dissipation member 7b. This effectively generates compressive stress throughout heat conductive layer 5.

[0053] (5) The biasing member 9 includes: a pair of inclined portions 11d, which are formed to extend in a direction away from the heat dissipation member 7b with the pair of pressing portions 9a and 9b as a reference in a cross section perpendicular to the extension direction; and a plurality of flange portions 11f, which are formed to extend outward from both ends of the pair of inclined portions 11d. The plurality of flange portions 11f include: a plurality of protrusions 11g, which respectively fix the fixing member 13 and are formed in a position between the arrangement of the plurality of semiconductor modules 100 and in a direction away from the semiconductor modules 100 when viewed from the direction in which the biasing member 9 presses the heat dissipation member 7b; and a connecting portion 11e, which is formed between the inclined portions 11d and the protrusions 11g and is formed along the extension direction. The load-bearing portions 11a and 11b are formed on the top side of the plurality of protrusions 11g. This generates elastic deformation relative to the biasing member 9 that receives the load, thereby achieving miniaturization, reducing the number of components, improving heat dissipation, and enabling efficient pressure in the stacking direction.

[0054] (6) The intermediate portion 9c has a flat plate shape and is parallel to the heat dissipation member 7b when the biasing member 9 is pressed against the heat dissipation member 7b by a load and in contact with the heat dissipation member 7b. This prevents damage to the heat dissipation member 7b and improves vibration resistance. Furthermore, compressive stress can be generated throughout the heat dissipation member 7b.

[0055] (7) The middle portion 9c has a plurality of convex ribs 9d on the surface opposite to the surface in contact with the heat dissipation member 7b. This increases the bending rigidity of the middle portion 9c and allows the heat dissipation member 7b to be pressed over a wider area.

[0056] (8) The ribs 9d are formed in a direction perpendicular to the extending direction of the pressing portions 9a and 9b. This can increase the bending rigidity of the intermediate portion 9c.

[0057] (9) In the urging member 9, the thickness T2 (T4) of the middle portion 9c is formed thicker than the thickness T1 (T3) of the other portions. This increases the bending rigidity of the middle portion 9c and applies the load to a wider range of the heat dissipating member 7b.

[0058] (10) In the biasing member 9, the angle θ2 formed by the intermediate portion 9c and the inclined portion 111d on the surface opposite to the surface in contact with the heat dissipation member 7b is an obtuse angle. This allows for efficient compression of the heat dissipation member 7 and the semiconductor module 100, resulting in a power semiconductor device with high heat dissipation performance and high reliability.

[0059] (11) Among the plurality of loaded portions 11a and 11b, the first spring constant of the loaded portions 11a formed at the four corners of the biasing member 9 is smaller than the second spring constant of the loaded portions 11b formed at locations other than the four corners, and the second spring constant is less than or equal to twice the first spring constant. This reduces the variation in compressive stress generated in each semiconductor module 100 when the spring plate member 9 presses the heat dissipation member 7b.

[0060] (12) The flange portion 11f has a tapered shape, thereby achieving weight reduction.

[0061] (13) Among the plurality of loaded portions 11a and 11b, the load applied to the loaded portions 11a formed at the four corners of the biasing member is greater than the load applied to the loaded portions 11b formed at positions other than the four corners. Thus, when the spring plate member 9 presses the heat dissipating member 7b, it is possible to reduce the variation in the compressive stress generated in each semiconductor module 100.

[0062] In addition, the present invention is not limited to the above-mentioned embodiment, and various modifications or other configurations can be combined within the scope of the present invention. In addition, the present invention is not limited to the structure having all the configurations described in the above-mentioned embodiment, and also includes a structure in which part of the configuration is deleted. Explanation of symbols

[0063] 1Power semiconductor components 2. Bonding materials 3First conductor 3b Second conductor 3c external terminal 4 insulation layers 5 thermal conductive layer 7First heat dissipation member 7b Second heat dissipation member 7d heat sink formation area 7e heat sink 7f hollow area 8Fixing flange 9 Spring plate member 9a, 9b pressurizing part 9c middle part 9d rib 9e middle convex part 10 Sealing resin 11 Load-carrying part 11a Load-bearing parts at the four corners 11b Loaded parts other than the four corners 11c Hole through which the first fixing member passes 11d inclined portion 11e connection 11f flange 11g protrusion 12 Second fixing member 13 first fixing member 15 middle layer 50Previous spring plate components 50a, 50b Conventional pressurizing unit 50c centerline 51a, 51b Conventional loaded parts 60 load direction 70 recess 70b convex part 100 semiconductor modules 100b semiconductor module placement area 101 small piece molded package.

Claims

1. A power semiconductor device, characterized in that: have: A plurality of power modules formed by molding and packaging semiconductor elements and a conductor plate bonded to the semiconductor elements; a heat dissipation member in contact with at least one surface of the power module via a heat conductive member; as well as an elastically deformable biasing member that presses the heat dissipating member toward the power module, The urging member includes: a pair of pressing portions that abut against the heat dissipating member; a plurality of loaded portions disposed outside the pair of pressurizing portions and receiving a load through a fixing member; and an intermediate portion disposed between the pair of pressurizing portions and generating a bending stress corresponding to the load, The plurality of power modules are arranged along the extending direction of the pair of pressurizing parts. When the biasing member presses the heat dissipating member, the intermediate portion is elastically deformed in a direction away from the heat dissipating member due to the bending stress.

2. The power semiconductor device according to claim 1, wherein The pair of pressing portions are formed at positions overlapping with a region where the semiconductor element is arranged, when viewed from a direction in which the biasing member presses the heat dissipating member.

3. The power semiconductor device according to claim 1, wherein In a cross section perpendicular to the extending direction, the pair of pressing portions are in contact with the heat dissipating member at positions between a center of the heat conducting member and both ends of the heat conducting member.

4. The power semiconductor device according to claim 1, wherein: The heat dissipating member has a hollow coolant flow path with heat dissipating fins arranged therein. The pair of pressing portions is formed in a region where the heat dissipation fin is arranged, when viewed from a direction in which the biasing member presses the heat dissipation member.

5. The power semiconductor device according to claim 1, wherein The urging member includes: a pair of inclined portions, which are formed to extend in a direction away from the heat dissipation member with the pair of pressing portions as a reference in a cross section perpendicular to the extending direction; and a plurality of flange portions, which are formed to extend outward from both ends of the pair of inclined portions. The plurality of flange portions include: a plurality of protrusions that respectively fix the fixing members and are formed at positions between the plurality of power modules and in a direction away from the power modules when viewed from a direction in which the biasing member presses the heat dissipation member; and a connecting portion that is formed between the inclined portion and the protrusions and is formed along the extending direction. The loaded portion is formed on the tip end side of the plurality of protrusions.

6. The power semiconductor device according to claim 1, wherein: The intermediate portion has a flat plate shape and is parallel to the heat dissipation member in a state where the biasing member is pressed against the heat dissipation member by the load and contacts the heat dissipation member.

7. The power semiconductor device according to claim 1, wherein: The intermediate portion has a plurality of convex ribs on a surface opposite to a surface in contact with the heat dissipating member.

8. The power semiconductor device according to claim 7, wherein: The rib is formed in a direction perpendicular to an extending direction of the pressing portion.

9. The power semiconductor device according to claim 1, wherein: In the urging member, the middle portion is formed to be thicker than other portions.

10. The power semiconductor device according to claim 5, wherein: In the urging member, an angle formed by the intermediate portion and the inclined portion on a surface opposite to a surface in contact with the heat dissipating member is an obtuse angle.

11. The power semiconductor device according to claim 1, wherein: Among the plurality of loaded portions, the loaded portions formed at the four corners of the urging member have a first spring constant smaller than a second spring constant of the loaded portions formed at positions other than the four corners. The second spring constant is less than or equal to twice the first spring constant.

12. The power semiconductor device according to claim 5, wherein: The flange portion has a tapered shape.

13. The power semiconductor device according to claim 1, wherein Among the plurality of load receiving portions, the load applied to the load receiving portions formed at the four corners of the urging member is greater than the load applied to the load receiving portions formed at positions other than the four corners.

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