Power semiconductor device

Abstract

Power semiconductor device formed by arranging a plurality of power modules (10) adjacently in an arc shape on a heat sink (21), wherein each power module (10) is formed by sealing with a molding resin (13), a switchable power semiconductor chip (12), a conductor frame (11) in which a potential line (14, 15) and a signal terminal (17) connected to the power semiconductor chip (12) are formed, and a metallic inner conductor (18) electrically connecting a top electrode of the power semiconductor chip (12) and the conductor frame (11), wherein at least one of the adjacent power modules (10) is formed in a pentagonal shape having a slanted side (10a) on a section directly adjacent to the other power module (10), the slanted side being obtained by cutting out a corner of a rectangle.

Description

BACKGROUND OF THE INVENTION 1. Technical Field

[0001] The present disclosure relates to a power semiconductor device and a power module for use in the power semiconductor device. 2. Description of the state of the art

[0002] In a power semiconductor device, a plurality of power modules, each containing a switchable power semiconductor chip and mounted on a heat sink, are combined to form a power conversion circuit.

[0003] In the power semiconductor device, a signal is transmitted from a control board, which is included alongside the power conversion circuitry, to the power conversion circuitry, and each power semiconductor chip is switched on and off, thereby controlling the power output. The power semiconductor device incorporates a smoothing capacitor to absorb voltage fluctuations and the noise generated during this process.

[0004] Furthermore, during operation of the power semiconductor device, power is transferred between these components via a busbar formed from a metallic plate, which connects a power source, the power modules and the smoothing capacitor.

[0005] A three-phase circuit is used as the power conversion circuit. For example, if two three-phase circuits are arranged in parallel, it is possible to reduce electromagnetic noise and smooth out variations in the drive torque when the three-phase circuits are connected to and operated by a motor.

[0006] Each power module is obtained or formed by mounting a power semiconductor chip onto a conductor frame which is configured in a wiring or circuit pattern, connecting an upper surface electrode pad of the power semiconductor chip by a wiring element and sealing these components with a molding resin or casting resin.

[0007] A power conversion circuit is formed by mounting a multitude of power modules on a heat sink, but it is necessary to arrange the power modules efficiently in order to provide a small-sized power semiconductor device.

[0008] For example, to obtain an n-phase power conversion circuit, it is necessary, for instance, in the case where a circuit for one phase is formed by a power module, to arrange n power modules at a heat sink, and the size of a power semiconductor device is determined by the external size of each power module.

[0009] For example, Japanese patent JP 6 038 230 B1 discloses the structure of a power semiconductor device equipped with power modules for n phases.

[0010] In the power semiconductor device, n power modules are arranged in an arc shape on a common heat sink to form an n-phase bridge circuit, which is provided on a body of a rotating electrical machine.

[0011] However, in the power semiconductor device disclosed in Japanese patent JP 6 038 230 B1, each power module has a rectangular shape, and it is necessary to arrange the power modules in such a way that the power modules do not interfere with each other, even if the power modules are arranged in an arc shape so that they are close together.

[0012] For example, if, in the case where n rectangular power modules are arranged in an arc, each of the lengths of the short sides of power modules A and B, extending in a direction perpendicular to the inner circumference of the arc, is denoted by L, as in Fig. As shown in Figure 7, even in a state where the power modules A and B are arranged closest to each other, a triangular gap C appears between the power modules A and B, which has a size with a base length of 2×L×sin(360 / 2 / n) and a height of L×cos(360 / 2 / n).

[0013] Consequently, it is necessary to provide a gap with a total size equal to or greater than n×L×sin(360 / 2 / n)×cos(360 / 2 / n) between the power modules A and B, which impairs the size reduction of the power semiconductor device.

[0014] Document DE 11 2014 006 573 T5 represents further prior art. According to its abstract, this document provides a module for use in power electronics, comprising a built-in semiconductor element used to provide and control a large amount of power, wherein the shaped module includes at least one semiconductor switching element provided within the module and a conductor frame that dissipates heat from the switching element and electrically connects an element arranged within the module to an external circuit, wherein at least one end of the module is shaped in a curved or polygonal form. PRESENTATION OF THE INVENTION

[0015] The present disclosure is designed to solve the above-mentioned conventional problems, and one object of the present disclosure is to provide a small-sized power semiconductor device in which interference between a plurality of adjacent power modules is prevented and the areas or regions of the gaps occurring between the power modules are reduced.

[0016] The present invention is defined by the power semiconductor device according to the features of independent claim 1. The dependent claims relate to optional further developments.

[0017] The power semiconductor device according to one aspect of the present disclosure is a power semiconductor device formed by arranging a plurality of power modules adjacent to each other in an arc shape on or at a heat sink, wherein each power module is obtained or formed by sealing a switchable power semiconductor chip, a conductor frame in which a potential conductor and a signal terminal connected to the power semiconductor chip are formed, and a metallic inner conductor electrically connecting a top electrode of the power semiconductor chip and the conductor frame with a molding resin, wherein at least one of the adjacent power modules is formed in a pentagonal shape having a slanted side at a section adjacent to the other power module, the slanted side being obtained or formed by cutting out or truncating a corner of a quadrilateral.

[0018] The power semiconductor device according to one aspect of the present disclosure can be realized as a small-sized power semiconductor device formed by the adjacent arrangement of a plurality of power modules, preventing interference between the adjacent power modules and reducing the areas of the gaps occurring between the power modules. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is an external schematic perspective view of a power module for use in a power semiconductor device according to a first embodiment of the present disclosure, seen from above a molded resin; Fig. 2 is a diagram that represents a circuit for a power module according to the first embodiment; Fig. 3 is a cross-sectional view along a line AA in Fig. 1; Fig. 4 is an external schematic view representing the power semiconductor device according to the first embodiment; Fig. Figure 5 is a circuit diagram showing an example in which the power semiconductor device is used according to the first embodiment; Fig. Figure 6 is a schematic diagram illustrating prohibited component mounting areas in a conventional power semiconductor device and in the power semiconductor device according to the first embodiment; and Fig. Figure 7 illustrates the case where conventional power modules are arranged in an arc shape. DETAILED DESCRIPTION OF THE PREFERRED VERSIONS OF THE FIRST INVENTIONAL VERSION

[0019] In the following, a first embodiment of the present disclosure is described with reference to the Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. 5 described.

[0020] Fig. Figure 1 is an external schematic perspective view of a power module 10 for use in a power semiconductor device 100 according to the first embodiment, seen from above a molded resin 13. Fig. Figure 2 is a diagram representing a bridge circuit formed by a power module 10.

[0021] The power module 10 comprises: a metallic conductor frame 11 formed in a wiring pattern shape; two power semiconductor chips 12 connected to the conductor frame 11; and the molding resin 13 arranged to cover part of the conductor frame 11 and the power semiconductor chips 12.

[0022] The power module 10 comprises a P-potential line 14 and an AC potential line 16, which are formed by being separated from the conductor frame 11 and equipped with the power semiconductor chips 12, and an N-potential line 15, which is not equipped with a power semiconductor chip.

[0023] In Fig. 1 The power module 10 is designed such that the outer shape of the molding resin 13 is a pentagonal shape with a slanted side 10a, which is obtained or formed by cutting out a corner of a square, the P-potential line 14 and the N-potential line 15 are arranged on the short side connected to the slanted side 10a, and signal connections 17 are arranged on the long side opposite the short side connected to the slanted side 10a.

[0024] As in Fig. As shown in Figure 3, the conductor frame 11 is formed into a wiring pattern shape by molding a plate made of an alloy containing copper or aluminum as a base. On one side of the conductor frame 11, the power semiconductor chips 12, conductive elements 20 such as solder, internal conductors 18, wire bond wiring (not shown), a current sensing resistor (not shown), and the like are mounted and sealed so that they are covered with the molding resin 13, and a portion not required for the electrical wiring or circuitry is removed.

[0025] Accordingly, the conductor frame 11 is separated and the P-potential line 14, the N-potential line 15 and the AC-potential line 16 are as shown in Fig. 1 shown designed so that a structure is provided in which these components are overmolded with a transfer molding resin.

[0026] Etching or pressing of a plate-shaped material is used for processing into a wiring pattern shape for the conductor frame 11, and a conductor frame can be used which has a metallic base exposed at the surface, but a conductor frame that is at least partially plated can also be used.

[0027] Each power semiconductor chip 12 has a chip top electrode and a chip bottom electrode on a top and a bottom surface thereof.

[0028] In the present embodiment, a MOSFET is shown as an example of the power semiconductor chip 12, but the power semiconductor chip 12 can also be applied to an IGBT. The MOSFET and the IGBT are switchable elements and each have a gate section and a gate electrode on the top side of the chip in addition to the top-side electrode.

[0029] The gate electrode is electrically connected to a gate terminal formed by part of the conductor frame (not shown) via wire bonding.

[0030] The power semiconductor chip 12 can be not only a chip manufactured using Si, but also a chip manufactured using SiC, SiN, GaN, GaAs or the like.

[0031] Furthermore, in the case of using a wiring element, such as an internal conductor, the top electrode of the power semiconductor chip has 12 specifications that enable soldering, for example a Ni-coated or plated layer for connecting to a conductive element, such as solder.

[0032] In the present embodiment, the chip top electrode of each power semiconductor chip 12 and each inner conductor 18, each inner conductor 18 and the conductor frame 11, and the chip bottom electrode of each power semiconductor chip 12 and the conductor frame 11 are connected to each other by soldering.

[0033] In the present embodiment, a current sensing resistor 19 is provided as an electronic component in the vicinity of the inner conductor 18.

[0034] The solder between each power semiconductor chip 12, each internal conductor 18, the current sensing resistor 19 and the conductor frame 11 can be joined by batch heat treatment using a reflow device or the like, thus improving productivity.

[0035] In the event that expansions occur due to a temperature change or the like during the use of the power semiconductor device 100, and thus a difference in durability may arise due to a soldered section, a solder with a different composition may be used for each location where the solder is to be applied.

[0036] In the present embodiment, the solder is shown as an example of the conductive element 20, but not only a conductive resin paste but also a sintering paste can be used.

[0037] Since in the present embodiment the outer shape of the power module 10 is designed as a pentagonal shape with a slanted side, which is obtained or formed by cutting out a corner of a quadrilateral, it is, in the case in which the power semiconductor device 100, corresponding to a pair of three-phase inverters, is formed by arranging six power modules 10 adjacently in an arc shape on a common heat sink 21, which is provided on a body of a rotating electrical machine, as in Fig. Figure 4 shows, in contrast to the case where rectangular power modules are arranged in an arc shape without a cutout, as in Fig. As shown in Figure 7, it is possible to arrange the power modules 10 so that the power modules 10 are closer together by an amount corresponding to the section of one corner of the quadrilateral, and thus the gap between the two adjacent power modules 10, 10 can be reduced compared to the case shown in Figure 7.

[0038] Fig. Figure 5 is a circuit diagram showing an example in which the power semiconductor device 100, corresponding to a pair of three-phase inverters, is used, and illustrates an example in which two three-phase DC motors 300 and 400 are driven by a DC source 200 via a pair of three-phase inverter circuits formed by the power semiconductor device 100.

[0039] Furthermore, in the present embodiment, in the case where six power modules 10 are arranged in an arc shape on the heat sink 21, as shown in Fig. As shown in Figure 4, each power module 10 has a structure in which the P-potential line 14 and the N-potential line 15 are arranged on the short side which is connected to the inclined side 10a which is obtained or formed by cutting out a corner of a quadrilateral, and the signal terminals 17 are arranged on the long side opposite the short side which is connected to the inclined side 10a.

[0040] Accordingly, if n power modules are arranged in an arc shape on a heat sink to form an n-phase bridge circuit, signal connections are located on the outer circumferential side of the arc formed by the power modules, and potential lines are located on the inner circumferential side of the arc. This means that soldering areas, where soldering takes place when connecting the signal connections to a control board, are concentrated on an outer circumferential section of the power semiconductor device. Thus, prohibited component mounting areas that occur alongside and are located near the soldering areas can be reduced, and the component mounting areas required to mount components in order to avoid these prohibited areas can be reduced, allowing the power semiconductor device to be designed with a small size.

[0041] In other words, since the signal connections and potential leads of the power modules are connected to the control board via solder, so that they extend through through holes or the like provided in the control board, in the case where the signal connections and potential leads of the power modules are located on four sides of power modules A and B, as shown in the left part of Fig. As shown in Figure 6, even if electronic components are arranged in an area inside or inwards of the terminals of the power modules connected to the control board, it is difficult to electrically connect the electronic components to an area outside the terminals. Therefore, the electronic components cannot be arranged inside the terminals, and the components cannot be mounted in an area inside the terminals and an area that has regions around the terminals, so that the area around the entire outer shape of each power module within the area of ​​the control board connected to the power modules is a forbidden component mounting area D.

[0042] By arranging the potential lines 14 and 15 on the inner circumferential side of the power module 10 and arranging the signal connections 17 on the outer circumferential side of the power module 10 as in the present embodiment, even if the electronic components are arranged in the area inwards of the connections, the prohibited component mounting areas D only need to be defined on the inner circumferential side and the outer circumferential side of the power module 10, as shown in the right part of Fig. 6 is shown, and it is possible to ensure an electrical connection within band-like areas formed by the signal terminals 17 and the potential lines 14 and 15, corresponding to an outer circumferential section of the power semiconductor device.

[0043] Since the soldering areas on the outer circumferential section of the power semiconductor device can be provided in a concentrated manner, the areas where soldering needs to be performed are limited, thus facilitating soldering and enabling the provision of a high-productivity power semiconductor device.

[0044] Since it is possible to arrange the P-potential line 14 and the N-potential line 15 next to each other, noise generated when a current is applied is reduced, there is no influence on the surrounding electronic components and electrical circuits, and noise shielding to prevent the influence of noise becomes unnecessary, so that the power semiconductor device can be designed with a small size.

[0045] As described above, according to the power semiconductor device disclosed in the present disclosure, in a power semiconductor device formed by adjacently arranging a plurality of power modules in an arc shape on a heat sink, wherein each power module is obtained or formed by sealing with a molding resin a switchable power semiconductor chip, a conductor frame in which a potential line and a signal terminal connected to the power semiconductor chip are formed, and a metallic inner line that electrically connects a top electrode of the power semiconductor chip and the conductor frame, at least one of the adjacent power modules is formed in a pentagonal shape having a slanted side on a section adjacent to the other power module, which is obtained or formed by cutting out a corner of a quadrilateral.In this way it is possible to arrange the adjacent power modules at a close distance and to reduce the area of ​​the gap between the power modules, so that a small-sized power semiconductor device can be formed.

[0046] According to the power semiconductor device disclosed in the present disclosure, a P-potential line and an N-potential line connected to the power semiconductor chip are arranged on a side corresponding to the inner circumferential side of each of the arc-shaped power modules. Thus, the P-potential line and the N-potential line can be positioned close together, noise generated when a current is applied is reduced, there is no influence on the surrounding electronic components and electrical circuits, and noise shielding to prevent the influence of noise becomes unnecessary, allowing for the design of a small-sized power semiconductor device.

[0047] According to the power semiconductor device disclosed in the present disclosure, the signal terminal connected to the power semiconductor chip is located on the side corresponding to the outer circumferential side of each of the arc-shaped power modules. This makes it possible to arrange the power modules close together, while the numerous signal terminals are concentrated on the outer circumferential side. By arranging the signal terminals in a concentrated manner, soldering areas, where soldering is required when connecting the signal terminals to a control board, are provided in a concentrated form on the outer circumferential section of the power semiconductor device.Thus, prohibited component mounting areas that occur alongside and are located near the soldering areas can be reduced, and component mounting areas that must be ensured for mounting components in order to avoid the prohibited component mounting areas can be reduced, so that a power semiconductor device can be designed with a small size.

[0048] The power semiconductor device disclosed in the present disclosure has a structure in which the entire assembly, comprising not only a substrate but also the chip and the wiring, is overmolded with a transfer molding resin. By forming the outer shape of each power module as a mold in which there is no corner with an angle of less than 90 degrees, the release from the mold during molding is good and the productivity is excellent.

[0049] Furthermore, in the power semiconductor device disclosed in the present disclosure, each power module is configured such that the conductor frame forms a wiring pattern for a substrate and has a structure in which the substrate and the electronic components mounted thereon are sealed with a transfer molding resin. Thus, by forming the outer shape of the molding resin as a pentagonal shape, even if any shape is chosen as the wiring pattern in which a semiconductor chip and electronic components are mounted, it is possible to arrange the power modules in an arc shape, since the outer shape formed by the molding resin is a pentagonal shape. DESCRIPTION OF REFERENCE MARKS 100 power semiconductor device 10 Power module 10a slanted side 11 ladder frames 12 Power semiconductor chip 13 Molding resin 14 P-potential line 15 N potential lead 16 AC potential conductor 17 Signal connection 18 inner guidance 19 Current sensing resistor 20 conductive element 21 Heat sink 200 DC power source 300, 400 three-phase DC motor

Claims

[1] Power semiconductor device formed by arranging a plurality of power modules (10) adjacent to each other in an arc shape on a heat sink (21), wherein each power module (10) is formed by sealing with a molding resin (13), a switchable power semiconductor chip (12), a conductor frame (11) in which a potential line (14, 15) and a signal terminal (17) connected to the power semiconductor chip (12) are formed, and a metallic inner conductor (18) electrically connecting a top electrode of the power semiconductor chip (12) and the conductor frame (11), wherein at least one of the adjacent power modules (10) is formed in a pentagonal shape having a slanted side (10a) on a section directly adjacent to the other power module (10) which is obtained by cutting out a corner of a rectangle. [2] Power semiconductor device according to claim 1, wherein the potential line (14, 15) is arranged on a side corresponding to an inner circumferential side of each of the power modules (10). [3] Power semiconductor device according to claim 1 or 2, wherein the signal connection (17) is arranged on a side corresponding to an outer circumferential side of each of the power modules (10). [4] Power semiconductor device according to any one of claims 1 to 3, wherein each of the power modules (10) has a bridge circuit for one phase, and the n power modules (10) are arranged in an arc shape on a common heat sink (21) to form an n-phase bridge circuit. [5] Power semiconductor device according to any one of claims 1 to 4, wherein the molding resin (13) is a transfer molding resin and the power semiconductor chip (12), the conductor frame (11) and the inner conductor are overmolded with it.

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