JP2013120756A - Semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor module electrically connecting an electrode layer and an electrode terminal of a semiconductor element by pressure-welding, which reduces a difference between pressure welding forces applied to the semiconductor elements, respectively.SOLUTION: A semiconductor module 1 comprises: lamination parts 2-4 in each of which single-phase 1-arm switches 2a, 2b each including a semiconductor element, an AC electrode terminal 5 and DC electrode terminals (P-terminal 6, N-terminal 7) are laminated; and a disc spring 8. The lamination parts 2-4 are provided on the same circumference of a circle centering a central axis B of the semiconductor module 1. On a top face of the lamination part 2 (or lamination part 3 or lamination part 4), a force transmission block 11 is provided via an insulating plate 10. On a top face of the force transmission block 11, a groove 11a is formed and the disc spring 8 is provided in the groove 11a. The disc spring 8 is provided coaxially with the central axis B. Each of the lamination parts 2-4 is provided from a part of a lower end peripheral part 8b, which contacts the force transmission block 11 on an axial extension of the central axis B.

Description

  The present invention relates to a semiconductor module that electrically connects an electrode layer and an electrode terminal of a semiconductor element by pressure welding.

  As a typical insulated power semiconductor module, there is an IGBT (Insulated Gate Bipolar Transistor) module used in a power converter such as an inverter. In addition, standards for “green green power semiconductor module” or “Isolated power semiconductor devices” represented by the IGBT module are established in JEC-2407-2007 and IEC60747-15, respectively.

  In general green power semiconductor modules, semiconductor elements such as IGBTs and diodes that are switching elements are made of copper on a DBC (Direct Bond Copper) substrate (or DCB substrate) with an electrode layer provided on the lower surface of the semiconductor element. It is soldered on the circuit foil and provided on the circuit (for example, Non-Patent Document 1). Here, the DBC substrate is obtained by directly bonding a copper circuit foil to an insulating plate made of ceramics or the like.

  The electrode layer provided on the upper surface of the semiconductor element is electrically connected to the copper circuit foil on the DBC substrate by connecting an aluminum wire by a method such as ultrasonic bonding. A copper terminal (lead frame or bus bar) for connecting electricity from the copper circuit foil of the DBC substrate to the outside is connected to the copper circuit foil by soldering or the like. Furthermore, this area is surrounded by a (super) engineering plastic case and filled with silicone gel for electric greening.

  In recent years, the operating temperature of semiconductor elements has been increasing. When the operating temperature is 175 to 200 ° C., since this temperature is close to the melting point of the solder material, there are cases where a conventional solder material cannot be used. Therefore, as a material to be replaced with solder, for example, metal-based high-temperature solder (Bi, Zn, Au), compound-based high-temperature solder (Sn—Cu), low-temperature sintered metal (Ag nanopaste), and the like have been proposed. In addition, SiC, which is a next-generation semiconductor element, has been reported to operate at 250 to 300 ° C.

  Further, a flat pressure contact structure package has been proposed as a semiconductor module structure that does not use solder (Non-Patent Documents 1 and 2).

  In the flat pressure contact structure package, the contact terminal and the electrode layer of the semiconductor element are connected and the semiconductor element and the substrate are connected by pressure contact. In a general flat pressure contact structure package, a guide for positioning the semiconductor element and the contact terminal is provided at an end portion of the semiconductor element (for example, IGBT, diode). Then, the semiconductor element is provided on a substrate (Mo substrate, DBC substrate, etc.) with the upper electrode layer of the semiconductor element in contact with the contact terminal. As described above, the contact terminal and the substrate are provided in the semiconductor module with the semiconductor element sandwiched therebetween.

  Since the flat pressure contact structure package has a flat structure, the semiconductor element can be cooled from both sides. For this reason, in general, both sides of the flat pressure contact structure package are pressed with heat sinks to cool both sides of the flat pressure contact structure package, and the heat sink is used as a conductive member. Further, since the flat type pressure contact structure package connects the semiconductor element and the electrode terminal by pressure welding, the semiconductor element is electrically and thermally connected to the outside without using solder.

  In a semiconductor module having a flat pressure contact structure, it is necessary to assemble the semiconductor module so that the pressure contact force is equally applied to each semiconductor element or the like. For example, for pressure welding, it is necessary to electrically insulate the heat sinks above and below the flat pressure welded structure package, and the flat pressure welded package is pressed by a leaf spring. It is necessary to apply evenly to the electrode posts. These have know-how, and if the pressure contact is poor, the semiconductor element may be destroyed. In addition, the user performs the pressure contact between the heat sink and the flat pressure contact structure package mainly. In addition, skill is required to make full use of the heat sink and the leaf spring for pressure contact, which prevents the miniaturization of the circuit. For these reasons, the flat type pressure contact structure package is applied to a limited apparatus, and a conventional type of insulated power semiconductor module that is easy to use is widely used instead.

  In order to improve the reliability of the temperature cycle, power cycle, etc. of this semiconductor module, it is necessary to improve the problems caused by the difference in thermal expansion coefficient of each member (semiconductor, metal, ceramics, etc.) constituting the semiconductor module. . For example, since the thermal expansion coefficients of copper and ceramics are different between the substrate and the copper base and between the substrate and the copper terminal, a shear stress acts on the solder connecting the copper and the ceramic when the temperature of the semiconductor module rises. This shear stress may cause cracks in the solder and increase the thermal resistance or peel off the electrode terminals. Similarly, the solder between the semiconductor element and the substrate may be cracked. In addition, stress may be generated due to the difference in thermal expansion between aluminum and the semiconductor element at the connection portion of the aluminum wire on the semiconductor element, and the aluminum wire may be fatigued.

  As the power density increases year by year, the soldering stress of the solder and the stress of the aluminum wire are increasing as the bonding temperature of each member constituting the semiconductor module such as between the electrode on the semiconductor element and the aluminum wire becomes higher. . On the other hand, it is necessary to design the structure of the semiconductor module so that the influence of thermal expansion does not become apparent over the period until the design life of the semiconductor module is reached. With the advent of wideband cap semiconductor elements that can be used at high temperatures such as SiC and GaN, there is a demand for further reduction of the effects of thermal expansion. Further, semiconductor modules that make use of the performance of semiconductor elements that can be used at high temperatures, such as SiC and GaN, are required to further improve the reliability of semiconductor modules such as temperature cycle and power cycle.

  Therefore, in order to achieve high reliability, environmental friendliness, and convenience of the semiconductor module at the same time, it is possible to easily realize double-sided cooling without using solder bonding or wire bonding, which is advantageous in terms of heat dissipation. Type insulated power semiconductor modules are in the spotlight again.

  As shown in FIG. 4, the double-sided cooling type pressure contact type semiconductor module 18 is provided with bolts 15 (through the case 17) on the outer periphery of the semiconductor module 18. The bolts 15 are fastened with nuts (not shown) so as to press the heat sinks 12 and 14 in the direction of the single-phase one-arm switches 2a and 2b made of semiconductor elements. In this way, by fixing the heat sinks 12 and 14 with the bolts 15 and nuts, the components constituting the semiconductor module 18 (AC electrode terminals 5, DC electrode terminals 6 and 7, and single-phase one-arm switch 2a, 2b etc.) is applied. Further, inside the semiconductor module 18, a solder 19 (or adhesive, resin, or the like) layer is provided at the joint between the single-phase one-arm switch 2a and the AC electrode terminal 5 (and the DC electrode terminal 6). The single-phase one-arm switch 2a and the AC electrode terminal 5 (and the DC electrode terminal 6) are electrically connected. That is, by using the solder 19, the constituent members constituting the semiconductor module 18 are bonded (or sealed) so that the pressure contact force applied to each constituent member is within an appropriate range, and all the single-phase 1's are included. The variation of the pressure contact force with respect to the arm switches 2a and 2b is not increased. As described above, in the press-contact type semiconductor module 18, each component member (particularly, a single phase) is obtained by using both the means for applying the press-contact force mechanically and the interface bonding forming technology using the solder 19 and the sealing technology using the resin or the like. The reliability of the semiconductor module 18 is ensured by controlling the pressure contact force applied to the one-arm switches 2a and 2b) within an appropriate range.

  However, in recent years, with higher power density and smaller size in power converters and the adoption of SiC elements, etc., as the temperature of power converters increases (downsizing of cooling mechanism), solder and resin bonding and sealing Materials are required to have resistance to high temperatures (for example, 200 ° C. or higher) and reliability, and material development for that purpose is progressing. However, the reliability when mounting high temperature materials is just beginning to be evaluated, and high temperature materials are more expensive than conventional materials.

  The conventional double-sided cooling and pressure-bonding structure is used to form all joints with only pressure applied from both sides, excluding the solder layer and resin layer, and the sealing layer. Concentration is unavoidable, and it is difficult to maintain parallelism between the upper and lower cooling surfaces. As a result, there is a problem that the contact pressure becomes excessive or small at a specific interface of the module constituent member.

JP-A-9-139395

IEEJ Technical Committee on High Performance and High Performance Power Devices and Power ICs, “Power Device and Power IC Handbook”, Corona, July 1996, p289, p336 Hiroshi Mori, Yasukazu Seki, “Recent Advances in Large Capacity IGBTs”, The Institute of Electrical Engineers of Japan, The Institute of Electrical Engineers of Japan, May 1998, Vol. 118 (5), pp. 274-277

  As described above, in a semiconductor module in which an electrode layer and an electrode terminal of a semiconductor element are electrically connected by pressure welding, a predetermined pressure welding is applied to each semiconductor element provided in the semiconductor module in order to improve the operation reliability of the semiconductor module. It is required to apply force. For example, due to the difference in the pressure contact force acting on each semiconductor element, a difference also occurs in the thermal resistance and contact resistance between the semiconductor element and the electrode terminal, and as a result, there is a possibility that a difference occurs in the operation of the semiconductor element.

  In view of the above circumstances, the present invention provides a semiconductor module in which an electrode layer and an electrode terminal of a semiconductor element are press-contacted to electrically connect the electrode layer and the electrode terminal of the semiconductor element. It aims to provide technology that contributes to reducing the difference.

  One aspect of the semiconductor module of the present invention that achieves the above object is a semiconductor module in which a plurality of stacked portions including a semiconductor element and an electrode terminal electrically connected to the semiconductor element are disposed, The parts are arranged on the same circumference.

  According to another aspect of the semiconductor module of the present invention that achieves the above object, in the semiconductor module, the stacked portions are arranged at equal intervals, and an elastic member that press-contacts the stacked portions is provided around the circumference of the stacked portion. It is characterized in that it is provided on the extension in the central axis direction.

  Another aspect of the semiconductor module of the present invention that achieves the above object is characterized in that, in the semiconductor module, the elastic member is a disc spring, and the disc spring is provided coaxially with the central axis.

  According to another aspect of the semiconductor module of the present invention that achieves the above object, in the semiconductor module, the stacked portion is provided on the extension in the central axis direction at a location where the elastic force accumulated in the disc spring is applied. It is characterized by.

  Another aspect of the semiconductor module of the present invention that achieves the above object is characterized in that an elastic force transmission member is provided between the stacked portion and the disc spring in the semiconductor module.

  According to another aspect of the semiconductor module of the present invention that achieves the above object, the elastic force transmitting member is used as a heat sink in the semiconductor module.

  Another aspect of the semiconductor module of the present invention that achieves the above object is characterized in that in the semiconductor module, a dent preventing member is provided between the disc spring and the elastic force transmitting member.

  According to another aspect of the semiconductor module of the present invention that achieves the above object, in the semiconductor module, a fixing member that fixes the stacked portion is symmetrical with respect to the central axis, outside the outer periphery of the disc spring, and the disc. It is characterized by being provided inside the inner circumference of the spring.

  Another aspect of the semiconductor module of the present invention that achieves the above object is characterized in that in the semiconductor module, a through-hole penetrating the semiconductor module is formed coaxially with the central axis.

  Another aspect of the semiconductor module of the present invention that achieves the above object is characterized in that in the semiconductor module, a heat sink is provided in the through hole.

  Another aspect of the semiconductor module of the present invention that achieves the above object is characterized in that, in the semiconductor module, the semiconductor module is formed in a columnar shape.

  According to the above invention, in the semiconductor module in which the electrode layer and the electrode terminal of the semiconductor element are pressed to electrically connect the electrode layer and the electrode terminal of the semiconductor element, the difference in the pressure contact force acting on each semiconductor element. Can contribute to the reduction.

It is an upper surface perspective view of the semiconductor module concerning the embodiment of the present invention. It is principal part sectional drawing of the semiconductor module which concerns on embodiment of this invention. (A) It is sectional drawing of a disc spring in embodiment of this invention, (b) It is a top view of the disc spring concerning embodiment of this invention. It is principal part sectional drawing of the semiconductor module which concerns on a prior art.

  A semiconductor module according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the top perspective view and the cross-sectional views shown in the following drawings all schematically show the semiconductor module according to the embodiment of the present invention. It does not necessarily match.

  FIG. 1 is a top perspective view of a semiconductor module 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part of the semiconductor module 1 according to an embodiment of the present invention. 2 is a cross-sectional view taken along line AA of the semiconductor module 1 shown in FIG.

  As shown in FIG. 1, a semiconductor module 1 according to an embodiment of the present invention includes a single-phase one-arm switch (a combination of an IGBT as a switching element and an FWD (Free Wheeling Diode) as a rectifying element) 2a and 2b. This is a module that constitutes a 6in1 three-phase bridge inverter by disposing three laminated portions 2 to 4 configured in 2in1 every 120 °. Each of the stacked portions 2 to 4 has an AC electrode terminal 5 that outputs an alternating current of each phase (U, V, W), and a DC electrode terminal (P terminal 6 and N terminal 7) connected to a DC power source. Each electrode terminal penetrates the outer peripheral side surface (case 17) of the semiconductor module 1 and is connected to an external circuit.

  As shown in FIG. 2, the semiconductor module 1 according to the embodiment of the present invention includes laminated portions 2 to 4 and a disc spring 8. The external shape of the semiconductor module 1 is a columnar shape, and a through hole 9 penetrating the semiconductor module 1 is formed coaxially with a cylinder axis (hereinafter, referred to as a central axis B of the semiconductor module 1).

  The laminated section 2 is composed of single-phase one-arm switches 2a, 2b, an AC electrode terminal 5, and a DC electrode terminal (P terminal 6, N terminal 7). Hereinafter, the laminated part 2 will be described in detail, but the same applies to the other laminated parts 3 and 4 arranged at equal intervals on the same circumference as the laminated part 2, and the same components are denoted by the same reference numerals. The description is omitted to avoid repetition.

  An emitter electrode layer is formed on the top surface of the switching element of the single-phase one-arm switch 2a, and a collector electrode layer is formed on the bottom surface of the switching element of the single-phase one-arm switch 2a (not shown). On the other hand, a collector electrode layer is formed on the upper surface of the switching element of the single-phase one-arm switch 2b, and an emitter electrode layer is formed on the lower surface of the switching element of the single-phase one-arm switch 2b (not shown). ). In the description of the embodiment, for convenience, the upper surface and the lower surface are used, but the vertical direction does not limit the present invention.

  The P terminal 6 is provided on the lower surface of the single-phase one-arm switch 2a, and is electrically connected to the collector of the switching element and the cathode of the rectifying element. An AC electrode terminal 5 is provided on the upper surface of the single-phase one-arm switch 2a, and the AC electrode terminal 5 is electrically connected to the emitter of the switching element and the anode of the rectifying element.

  The N terminal 7 is provided on the lower surface of the single-phase one-arm switch 2b and is electrically connected to the emitter of the switching element and the anode of the rectifying element. An AC electrode terminal 5 is provided on the upper surface of the single-phase one-arm switch 2b, and the AC electrode terminal 5 is electrically connected to the collector of the switching element and the cathode of the rectifying element.

  The AC electrode terminal 5 and the DC electrode terminal (P terminal 6, N terminal 7) are taken out from the outer peripheral side surface of the semiconductor module 1, and the AC electrode terminal 5 is connected to an AC load such as a rotating machine, and the DC electrode terminal (P terminal 6). , N terminals 7) are connected to a DC power source side such as a battery. A smoothing capacitor may be arranged at each P terminal 6 and N terminal 7 for the purpose of suppressing ripples (pulsation components included in direct current) of a DC power source such as a battery.

  A force transmission block 11 is provided on the upper surface of the AC electrode terminal 5 via an insulating plate 10. A groove 11a in which an elastic member such as a disc spring 8 is provided is formed on the upper surface of the force transmission block 11, and the disc spring 8 is provided in the groove 11a. The force transmission block 11 is made of, for example, aluminum (more preferably, the purity is 99.99% or more) or an aluminum alloy. The force transmission block 11 functions as a stress relieving member by using a material having lower rigidity than the other members constituting the semiconductor module 1 for the force transmission block 11. As a result, the elastic force of the disc spring 8 can be applied to the stacked portions 2 to 4 more uniformly.

  The disc spring 8 is provided coaxially with the central axis C (the central axis B of the semiconductor module 1) of the same circumference where the stacked portions 2 to 4 are provided. As shown in FIG. 3A, the disc spring 8 generally has a shape with a hole in the center, and the distance between the upper and lower circumferential portions 8a and 8b of the disc spring 8 is short. As a result, elastic force is accumulated. Further, as shown in FIG. 3 (b), the places where the elastic force accumulated in the disc spring 8 is applied are an upper end circumferential portion 8a and a lower end circumferential portion 8b, and the upper end circumferential portion 8a or the lower end circumferential portion. The elastic force accumulated in the disc spring 8 acts on the portion in contact with the portion 8b.

  As shown in FIG. 2, the stacked portions 2 to 4 are stacked in the axial direction of the central axis B of the semiconductor module 1, and the center of the semiconductor module 1 is started from the portion where the lower circumferential portion 8 b of the disc spring 8 is in contact with the force transmission block 11. If the disc spring 8 is provided so that the laminated portions 2 to 4 are positioned on the axial extension of the axis B, the elastic force of the disc spring 8 can be directly applied to the laminated portions 2 to 4. Therefore, the physical distance required for diffusing the elastic force of the disc spring 8 to uniformly act on the stacked portions 2 to 4 can be shortened. As a result, the distance between the laminated portions 2 to 4 and the disc spring 8 can be shortened, and not only the elastic force of the disc spring 8 applied to each laminated portion 2 to 4 is made uniform, but also the semiconductor module 1 It can be downsized.

  In addition, by providing a dent prevention member (not shown) between the disc spring 8 and the force transmission block 11 or between the disc spring 11 and the heat sink 12 described later, the force transmission block 11 and the heat sink 12 are It is possible to prevent deformation due to the elastic force of the spring 8. The dent-preventing member may be a plate having a thickness of 0.5 mm or more made of a material having the same strength (or higher) as the disc spring 8 such as a washer-like plate or a disc-like plate made of stainless steel. If the thickness of the dent prevention member is 0.5 mm or more, the elastic force of the disc spring 8 is dispersed by the dent prevention member, and pressure that does not deform the force transmission block 11 and the heat sink 12 is applied to the force transmission block 11 and the heat sink 12. Can act.

  The DC electrode terminals (P terminal 6 and N terminal 7) are provided with a heat sink 14 via an insulating plate 13, and a heat sink 12 is provided on the force transmission block 11. The heat sinks 12 and 14 may have a fin shape (air cooling) or may be provided with a mechanism (liquid cooling) for circulating the refrigerant. And the bolt 15 (fixing member) in which the external thread part was formed is inserted in the edge part (outer peripheral end or inner peripheral end) of the heat sinks 12 and 14 (and the force transmission block 11 etc.), and the external thread part of the bolt 15 is the heat sink. 14 is screwed into the female screw portion 14a formed on the screw 14.

  With this bolt 15, each member constituting the semiconductor module 1 is fixed while maintaining a distance in the upper and lower thickness directions (between the heat sinks 12 and 14) of the semiconductor module 1, and a predetermined compressive displacement is given to the disc spring 8. . Elastic force is accumulated in the disc spring 8 by fixing the heat sinks 12 and 14 with bolts 15 so as to press the laminated portions 2 to 4 sandwiched between the heat sinks 12 and 14, the disc spring 8, and the like. Due to this elastic force, a pressing force acts on the laminated portion 2 (and the laminated portions 3 and 4). That is, the laminated part 2 (and the laminated parts 3 and 4) are laminated in the direction of the central axis B of the semiconductor module 1, and the disc spring 8 is provided so as to press-contact the laminated part 2, whereby the AC electrode terminal 5, P The terminal 6 is pressed by the single-phase one-arm switch 2a (or the AC electrode terminal 5 and the N terminal 7 are pressed by the single-phase one-arm switch 2b), and the AC electrode terminal 5, the P terminal 6 and the single-phase The one-arm switch 2a (or the AC electrode terminal 5, the N terminal 7 and the single-phase one-arm switch 2b) is electrically connected. Further, heat sinks 12 and 14 are provided at both ends of the semiconductor module 1 to form a double-sided cooling structure, thereby cooling the stacked portions 2 to 4 (that is, single-phase one-arm switches 2a and 2b) from both sides of the semiconductor module 1. can do.

  As shown in FIG. 1, the bolt 15 is located at a position inside the disc spring 8 (that is, inside the innermost peripheral side of the groove portion 11 a) and outside the disc spring 8 (that is, outside the outermost outer periphery of the groove portion 11 a). Several places are provided. Furthermore, by providing the bolts 15 so that the distances from the laminated parts 2 to 4 adjacent to the bolts 15 are equal, the force tightened by the bolts 15 is applied equally to the laminated parts 2 to 4. . The bolts 15 can be evenly arranged on concentric circles such as three at 120 ° intervals or six at 60 ° intervals, so that the pressure contact force applied to each of the stacked portions 2 to 4 can be equalized.

  As shown in FIG. 2, a heat sink 16 mechanically connected to the heat sinks 12, 14 or the force transmission block 11 is provided on the inner peripheral side surface of the through hole 9 formed coaxially with the central axis B of the semiconductor module 1. It is done. The heat sink 16 may have a fin shape (air cooling) or may be provided with a mechanism (liquid cooling) for circulating the refrigerant. The heat sink 16 promotes heat dissipation of the heat generated inside the semiconductor module 1 and promotes heat transfer from the side surface of the inner peripheral surface of the semiconductor module 1 to the atmosphere. As a result, the heat dissipation of the semiconductor module 1 is improved.

  As described above, as described in the specific embodiment, according to the semiconductor module according to the present invention, by disposing the stacked portions including the semiconductor elements on the same circumference, the heat dissipation condition of each stacked portion is It becomes the same and each laminated part can be cooled uniformly. As a result, a change in the pressing force due to the influence of thermal expansion of each stacked portion is suppressed, and the pressing force acting on each stacked portion becomes uniform.

  Moreover, when pressing a plurality of laminated portions with a single disc spring, a uniform pressure contact force is applied to the plurality of laminated portions by arranging the laminated portions on the same circumference around the central axis of the disc spring. be able to. As a result, in the semiconductor module that operates the stacked portions in parallel, the pressure contact force applied to each stacked portion (that is, the semiconductor element) becomes uniform, and the current concentrates on the specific stacked portion (or semiconductor element). Problems can be prevented. In addition, the number of components constituting the semiconductor module is reduced, and the convenience of assembling the semiconductor module is improved.

  Also, by providing a laminated portion on the extension of the central axis of the semiconductor module from the location where the elastic force accumulated in the disc spring acts (for example, directly below the lower circumferential portion of the disc spring), the laminated portion and the disc spring Even when a physical distance for diffusing the elastic force is not ensured during this period, a more uniform pressure contact force can be applied to the laminated portion. That is, when the disc spring is pressed vertically from above and below by a fixing member such as a bolt, the elastic force of the disc spring is constant at the lower end circumferential portion (or upper end circumferential portion) of the disc spring regardless of the position. Therefore, the thickness of the force transmission block (thickness in the central axis direction) is reduced by arranging the laminated portion directly below the place where the elastic force of the disc spring acts, and the distance between the disc spring and the laminated portion is reduced. Even in a short case, a uniform pressure contact force can be applied to all the laminated portions. Therefore, the thickness of the force transmission block can be reduced, and the semiconductor module can be reduced in size (particularly, the size of the semiconductor modules in the stacking direction can be reduced). Furthermore, by reducing the size of the semiconductor module, the distance between the heat sink and the semiconductor element is shortened, and the heat dissipation of the semiconductor module is improved.

  Further, by forming a groove portion for providing an elastic member such as a disc spring in the force transmission block, the disc spring can be easily positioned and the elastic force of the disc spring can be applied uniformly to each laminated portion. . In addition, by using this force transmission block integrally with the heat sink provided in the force transmission block (or using the force transmission block as a heat sink), the heat dissipation of the semiconductor module is improved and the disc spring provided in the force transmission block Is always cooled, and the change in elastic force due to the temperature change of the disc spring can be reduced. Furthermore, if a dent preventing member is provided between the disc spring and the force transmission block, the force transmission block is prevented from being deformed (dent) due to the elastic force of the disc spring, and the elastic force of the disc spring acts on the laminated portion more uniformly. .

  When realizing a semiconductor module that presses and cools a semiconductor element from both sides of the semiconductor module, it is necessary to parallelize the stacked portion including the semiconductor element in order to realize a high-current module, and a full-bridge three-phase inverter In order to realize the above, for example, it is necessary to arrange three 2-in-1 single-phase inverters in parallel, so that the entire semiconductor module has a large number of parts. For this reason, it is necessary to provide a structure that press-contacts the respective stacked portions with 1: 1 and a number of mechanisms (for example, screws and springs) for applying a pressing force, and the number of parts increases. Then, due to the increase in the number of parts, there is a concern that the reliability of the semiconductor module is reduced, the semiconductor module is enlarged, and the cost is increased.

  In order to avoid these concerns, when performing a plurality of laminated parts with as few mechanical mechanisms as possible (springs and screws), in order to suppress variations in the pressure contact force applied to each laminated part, the place where the spring is disposed, the spring A precise mechanical design is required, such as the spring constant, the place to be tightened with screws, and the tightening force. In addition, in order to uniformly transmit the force generated by one spring to a plurality of laminated portions, it is necessary to uniformly distribute and transmit the local strong force generated immediately below the spring to the plurality of laminated portions. A certain physical distance is required in order to spread the force in a direction perpendicular to the pressing direction.

  In the semiconductor module according to the present invention, the number of parts constituting the semiconductor module can be reduced because the stacked module is pressed by a single disc spring. Furthermore, each laminated portion is provided on the extension in the pressure-contact direction of the portion where the pressure contact force of the disc spring is applied. Therefore, even when the distance between the disc spring and the laminated portion is shortened, each laminated portion is applied. The pressure contact force becomes equal. As a result, the distance between the disc spring and the stacked portion can be shortened, and the entire semiconductor module can be downsized. That is, the miniaturization of the semiconductor module and the uniform pressure contact of the semiconductor element can be realized at the same time.

  Moreover, by making the outer shape of the semiconductor module cylindrical, it can be directly attached to the same cylindrical rotating machine or motor. As a result, it is possible to reduce the size of the device by integrally configuring the drive device and the power conversion device, and to reduce the inductance of the semiconductor module by providing the power conversion device in the vicinity of the drive device. Lowering the inductance of a semiconductor module leads to a reduction in surge voltage during switching. The outer shape of the semiconductor module is not necessarily limited to a cylindrical shape, and the design of the outer shape can be changed as appropriate, for example, it is formed in a prismatic shape.

  In addition, the semiconductor module of the present invention increases the module size in a power module that configures a power converter by parallelly stacking a plurality of semiconductor elements including a plurality of semiconductor elements, such as a SiC chip. In addition, all the semiconductor elements (laminated portions) can be uniformly pressed. Furthermore, since the variation in the pressure contact force applied to each stacked portion (and each semiconductor element) is reduced, the thermal resistance (and contact resistance) between the semiconductor element and the heat sink becomes substantially equal, and during the switching operation of the semiconductor element, The operation characteristics during steady operation can be made equal.

  Further, not only the heat dissipation of the semiconductor module but also the convenience of assembly can be improved, so that high reliability and convenience of the semiconductor module can be realized at the same time. In addition, since each member provided in the semiconductor module is connected by the elastic force of the disc spring, it is possible to obtain an easy-to-use insulated power semiconductor module without using solder bonding or wire bonding. Therefore, in a semiconductor module that takes advantage of the performance of a semiconductor element that can be used at high temperatures, such as SiC and GaN, the reliability of temperature cycle, power cycle, etc. is improved.

  In addition, the semiconductor module of the present invention can form a reliable module while suppressing the use of a bonding agent and a sealing material as much as possible only by a mechanical mechanism such as a spring. Factors that damage the reliability of the module are reduced, and a highly reliable module capable of handling high temperatures can be configured.

  Since the semiconductor module of the present invention can improve the heat dissipation of the semiconductor module, the semiconductor module can be used in an insulating power semiconductor module, an inverter or other power conversion device that requires high-temperature operation. The heat dissipation of the semiconductor module can be improved.

  Note that the semiconductor module of the present invention is not limited to the above-described embodiment, and the design can be changed as appropriate without departing from the characteristics of the present invention, and the modified form is also the semiconductor module according to the present invention. .

  For example, in the description of the semiconductor module according to the embodiment, the semiconductor module formed by combining a plurality of technical features of the semiconductor module according to the present invention has been described as an example, but includes a part of the technical features of the present invention. Even with a semiconductor module, the effects of the present invention can be partially obtained.

  Further, in the embodiment, the description has been given by exemplifying the laminated portion including two single-phase one-arm switches provided with one switching element and one rectifying element. However, the type and number of semiconductor elements (and the number of laminated portions) The number and the configuration of the stacked portions can be appropriately changed according to the use of the semiconductor module. In other words, the semiconductor module can be used as a power conversion device such as an inverter or a converter, and a semiconductor element such as an IGBT, a thyristor (GTO thyristor, etc.), a transistor (MOSFET, etc.), a diode (FWD), etc. Etc.) is selected. Specifically, when a semiconductor module is used as an inverter, an inverter circuit in which a plurality of switching elements and diodes are incorporated in parallel is formed. On the other hand, when using a semiconductor module as a converter, a converter circuit is comprised only by a rectifier element (diode).

  Also, in the description of the embodiment, a 2-in-1 stack unit is configured by using two single-phase one-arm switches, and this stack unit is arranged at three positions every 120 ° to form a 6-in-1 three-phase bridge inverter. However, the semiconductor module of the present invention is not limited to this example. For example, in order to increase the current capacity of the inverter, six stacked portions with the same rating are arranged in parallel every 60 °. The number of stacked portions, such as constituting a semiconductor module, can be set according to the application of the semiconductor module. That is, the laminated parts corresponding to each phase (for example, U, V, W) may be arranged at equal intervals.

  Further, when a sealing material such as a resin is filled in the gap between the laminated portions or the space between the laminated portion and the case, the mutual positional relationship of the members constituting the laminated portion can be kept constant, and each electrode terminal and A potential difference between the heat sinks can be ensured. Moreover, you may form an uneven surface in the surface of each member which comprises semiconductor modules, such as a laminated part (each member which comprises a laminated part), an insulating board, a heat sink, and a force transmission block. In this case, even when a vibration load is applied to the entire module by mechanically fitting the concavo-convex surfaces formed on the surfaces of the members that are in contact with each other, the mutual positional relationship of the members constituting the semiconductor module Therefore, it is possible to prevent excessive displacement and electrical short circuit in the semiconductor module.

  In the description of the embodiment, the semiconductor chip is illustrated below the lower circumferential portion of the disc spring. However, the upper circumferential portion of the disc spring has an electrode terminal as a single-phase one-arm switch (semiconductor element). The form which presses in a direction may be sufficient. Further, although a disc spring is preferable, the laminated portion may be pressed by using an elastic member such as a wave plate spring, a convex spring, or a mesh spring. The position where the elastic member is provided is not limited to the embodiment, and is provided so as to press the DC electrode terminal toward the semiconductor element (for example, in the semiconductor module 1 of FIG. Etc.), and the like, provided that the pressure contact force can be applied to the laminated portion.

  Further, the arrangement direction of the single-phase one-arm switch is such that the single-phase one-arm switch is arranged so as to be orthogonal to the tangent of the same circumference as in the semiconductor module shown in FIG. Alternatively, for example, a single-phase one-arm switch may be arranged in the tangential direction of the same circumference.

  In addition, it is preferable to dispose the laminated portion directly below (or directly above) the elastic member that is a source of pressure generation, since the distance between the laminated portion and the elastic member can be shortened. It is not necessary to dispose directly under the elastic member, and the elastic member may be disposed on the same circumference of the portion not directly under the elastic member as long as the elastic force of the elastic member is uniformly applied to each laminated portion.

  The fixing member is not limited to screwing the bolt into the heat sink, but can be fastened so that the distance between the upper and lower surfaces of the elastic member becomes a predetermined value, such as fastening with a bolt and a nut. Any known fixing method may be used. The number and arrangement of the fixing members can be arbitrarily set as long as the pressure contact forces applied to the respective stacked portions are equal.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor module 2-4 ... Laminate part 2a, 2b ... Single phase 1 arm switch 5 ... AC electrode terminal 6 ... DC electrode terminal (P terminal)
7 ... DC electrode terminal (N terminal)
8 ... Belleville spring (elastic member)
8a ... Upper end circumferential portion 8b ... Lower end circumferential portion 9 ... Through holes 10, 13 ... Insulating plate 11 ... Force transmission block (elastic force transmission member)
12, 14, 16 ... heat sink 15 ... bolt (fixing member)
17 ... Case

Claims (11)

A semiconductor module in which a plurality of stacked portions including a semiconductor element and an electrode terminal electrically connected to the semiconductor element are arranged,
A semiconductor module, wherein the stacked portions are arranged on the same circumference. The laminated parts are arranged at equal intervals,
2. The semiconductor module according to claim 1, wherein an elastic member that press-contacts the stacked portion is provided on an extension in a central axis direction of the circumference of the stacked portion. The elastic member is a disc spring,
The semiconductor module according to claim 2, wherein the disc spring is provided coaxially with the central axis. 4. The semiconductor module according to claim 3, wherein the stacked portion is provided on the extension in the central axis direction of a portion to which the elastic force accumulated in the disc spring is applied. The semiconductor module according to claim 3, wherein an elastic force transmission member is provided between the stacked portion and the disc spring. The semiconductor module according to claim 5, wherein the elastic force transmission member is used as a heat sink. The semiconductor module according to claim 5, wherein a dent preventing member is provided between the disc spring and the elastic force transmitting member. The fixing member for fixing the laminated portion is provided on the outer side of the outer periphery of the disc spring and on the inner side of the inner periphery of the disc spring, respectively, symmetrical to the central axis. 2. The semiconductor module according to claim 1. The semiconductor module according to claim 2, wherein a through-hole penetrating the semiconductor module is formed coaxially with the central axis. The semiconductor module according to claim 9, wherein a heat sink is provided in the through hole. The semiconductor module according to claim 1, wherein the semiconductor module is formed in a columnar shape.

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