Semiconductor module and vehicle

Abstract

To reduce a variation in switching operation between a plurality of switching elements that are connected in parallel.SOLUTION: A semiconductor module (1) comprises: a second wiring member (53, 57) for connecting each of the second main electrodes (301) of a plurality of semiconductor elements connected in parallel to a second conductor pattern (202) in which a main current flows; and a third terminal (807) connected to the second conductor pattern via a third wiring member (74). Each of the plurality of semiconductor elements includes a switching element having a control electrode for controlling a current flowing between the first main electrode and the second main electrode. The third wiring member includes a plurality of wiring members (74D-74F) associated with the plurality of semiconductor elements, respectively. The distance from connecting points (K1-K3) of the plurality of wiring members to a connecting point (K0) of the second wiring member on the second conductor pattern differs depending on the distance from a prescribed position of the third terminal to the connecting point of the second main electrode and second wiring members (57D-57F).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a semiconductor module and a vehicle. [Background technology]

[0002] Semiconductor modules used in power conversion devices include those in which multiple IGBT (Insulated Gate Bipolar Transistor) elements are connected in parallel. Some of these semiconductor modules are provided with a conductive member called an auxiliary emitter for connecting the emitters of the IGBT elements to a gate drive circuit that connects the gates of the multiple IGBT elements connected in parallel (for example, Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-167403 [Patent Document 2] International Publication No. 2020 / 054806 [Patent Document 3] International Publication No. 2022 / 059251 [Patent Document 4] International Publication No. 2022 / 264851 Summary of the Invention [Problem to be solved by the invention]

[0004] In a semiconductor module equipped with an auxiliary emitter, uneven switching behavior in each of the multiple IGBT elements connected in parallel can cause variations in heat generation among the IGBT elements, which can reduce the reliability of the semiconductor module.

[0005] One object of the present invention is to reduce variations in switching operation among a plurality of switching elements connected in parallel in a semiconductor module. [Means for solving the problem]

[0006] A semiconductor module according to one embodiment includes a wiring board having a first conductor pattern and a second conductor pattern arranged on one surface of an insulating substrate, a plurality of semiconductor elements arranged on the first conductor pattern of the wiring board, a first wiring member connecting each of the first main electrodes of the semiconductor elements to the first conductor pattern, a second wiring member connecting each of the second main electrodes of the semiconductor elements to the second conductor pattern, first terminals connected to the first main electrodes of the semiconductor elements via the first conductor pattern and through which a main current flows, second terminals connected to the second main electrodes of the semiconductor elements via the second conductor pattern and through which a main current flows, and a third terminal connected to the second conductor pattern via a third wiring member. Each of the semiconductor elements includes a switching element that controls the current flowing between the first main electrode and the second main electrode. The third wiring member includes a plurality of wiring members associated with each of the semiconductor elements. The distance from the connection points of the plurality of wiring members on the second conductor pattern to the connection points of the second wiring member varies depending on the distance from a predetermined position on the third terminal to the connection points of the second main electrodes of the plurality of semiconductor elements with the second wiring member. [Effects of the Invention]

[0007] According to the above-described aspect, it is possible to reduce variations in switching operation among a plurality of switching elements connected in parallel in a semiconductor module. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view of a semiconductor module according to an embodiment; [Figure 2] 2 is a cross-sectional view illustrating an example of the configuration inside a case of the semiconductor module of FIG. 1. FIG. [Figure 3] 2 is a partially enlarged cross-sectional view illustrating an example of the configuration of auxiliary emitter wiring in the semiconductor module of FIG. 1. FIG. [Figure 4] 2 is an equivalent circuit diagram of an inverter circuit formed in the semiconductor module of FIG. 1. [Figure 5] FIG. 5A is an equivalent circuit diagram illustrating an example of the inductance of an auxiliary emitter wiring in a semiconductor module according to one embodiment, and FIG. 5B is a graph illustrating an example of a switching operation in a semiconductor module according to one embodiment. [Figure 6] 10 is a partially enlarged plan view illustrating a conventional example of auxiliary emitter wiring in a semiconductor module in which a plurality of semiconductor elements are connected in parallel. FIG. [Figure 7] 7A is an equivalent circuit diagram illustrating an example of the inductance of the auxiliary emitter wiring in the semiconductor module of FIG. 6, and FIG. 7B is a graph illustrating an example of the switching operation in the semiconductor module of FIG. [Figure 8] FIG. 10 is a partially enlarged plan view illustrating a modified example of the semiconductor module according to the embodiment. [Figure 9] 1 is a schematic plan view showing an example of a vehicle to which a semiconductor module according to the present invention is applied; DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, a "semiconductor module" refers to a semiconductor element, which may also be called a semiconductor chip or die, sealed with an insulating material. The semiconductor module may also be called a "semiconductor device."

[0010] The X-axis, Y-axis, and Z-axis in each of the referenced figures are shown for the purpose of defining planes and directions in the semiconductor module shown. The X-axis, Y-axis, and Z-axis are perpendicular to each other and form a right-handed system. In the following description, the direction parallel to the X-axis is referred to as the X-direction, the direction parallel to the Y-axis is referred to as the Y-direction, and the direction parallel to the Z-axis is referred to as the Z-direction. Furthermore, when relating the X-axis, Y-axis, and Z-axis to the arrow directions (positive and negative) of the X-axis, Y-axis, and Z-axis shown in the figures, the X-axis, Y-axis, and Z-axis directions are labeled as the "positive side" or "negative side."

[0011] In this specification, the Z direction may be referred to as the up-down direction. In this specification, "up" and "above" refer to the positive side of the Z direction relative to a reference surface, component, position, etc., while "down" and "below" refer to the negative side of the Z direction relative to a reference surface, component, position, etc. For example, when describing "component B being placed on component A," component B is placed on the positive side of component A in the Z direction. Furthermore, when describing "the top surface of component A," this surface includes the surface located at the end of component A on the positive side of the Z direction and facing the positive side of the Z direction. These directions and surfaces associated with these directions are terms used for convenience of explanation, and their correspondence with the X-axis, Y-axis, and Z-axis directions may change depending on the mounting orientation of the semiconductor module, etc. For example, in this specification, the surface of a semiconductor element facing a wiring board is referred to as the bottom surface, and the surface opposite the bottom surface is referred to as the top surface. However, this is not limited thereto; the surface facing the wiring board may be referred to as the top surface, and the surface opposite the top surface may be referred to as the bottom surface.

[0012] The aspect ratios and relative sizes of components in each diagram are merely schematic representations and do not necessarily correspond to the relationships in an actually manufactured semiconductor module. For the sake of convenience, the relative sizes of components may be exaggerated or may differ from the external shapes of components used in an actual semiconductor module. Furthermore, for the sake of convenience, some cross-sectional views show the cross-sectional configuration of a semiconductor module cut along an imaginary cutting line that cannot be accurately shown in a plan view.

[0013] In this specification, the terms "not shown," "not shown," "not shown," and the like are intended to indicate without using a specific reference symbol or a leading line which part in the figure corresponds to the component to which the term is attached. For example, "first main electrode not shown" indicates both that a part (e.g., a shape, a line, etc.) representing the first main electrode is not shown in the figure and that there is no reference symbol or leading line clearly indicating the part corresponding to the first main electrode in the figure. Furthermore, an underlined reference symbol in the figure indicates the entire component including multiple parts distinguished by multiple reference symbols.

[0014] The semiconductor module exemplified in the following description may be applied to a power conversion device such as an inverter device for industrial or electrical equipment (e.g., an in-vehicle motor). For this reason, the following description will omit detailed descriptions of configurations, functions, operations, manufacturing methods, etc. that are identical to or similar to those of known semiconductor modules.

[0015] FIG. 1 is a plan view of a semiconductor module according to one embodiment. FIG. 2 is a cross-sectional view illustrating an example of the configuration inside a case of the semiconductor module of FIG. 1. FIG. 3 is a partially enlarged cross-sectional view illustrating an example of the configuration of auxiliary emitter wiring in the semiconductor module of FIG. 1. FIG. 4 is an equivalent circuit diagram of an inverter circuit formed in the semiconductor module of FIG. 1. The cross-sectional view of FIG. 2 may be an example of the cross-sectional configuration of the semiconductor module 1 taken along the dashed dotted line A-A' in the semiconductor module 1 of FIG. 1.

[0016] Semiconductor module 1 according to this embodiment includes wiring boards 2A and 2B, semiconductor elements 3A-3F, 4A-4F, wiring members 51-59, 61-66, 71-76, case 8, sealing material (not shown), and heat sink 10. In this specification, when multiple identical components are to be distinguished from one another, a reference symbol consisting of a number followed by an alphabetic character is used; when no distinction is required, only the number is used. For example, when referring to a specific semiconductor element among multiple semiconductor elements 3A-3F, the reference symbol (any of 3A-3F) assigned to that specific semiconductor element in FIG. 1 is used; otherwise, the element is simply referred to as "semiconductor element 3."

[0017] The wiring board 2 is an element-mounting component that mounts semiconductor elements 3 and 4, which are sometimes called semiconductor chips or dies. The semiconductor element 3 is a switching element such as an IGBT (Insulated Gate Bipolar Transistor), and the semiconductor element 4 is a diode element such as an FWD (Free Wheeling Diode). The wiring board 2, the semiconductor element 3, and the semiconductor element 4 are circuit components that form the half-bridge inverter circuit shown in FIG. 4.

[0018] Wiring board 2A includes an insulating substrate 200A, conductive patterns 201A-207A arranged on the upper surface of insulating substrate 200A, and heat dissipation pattern 208A arranged on the lower surface of insulating substrate 200A. Wiring board 2B includes an insulating substrate 200B, conductive patterns 201B-206B arranged on the upper surface of insulating substrate 200B, and heat dissipation pattern 208B arranged on the lower surface of insulating substrate 200B. Wiring board 2 may be, but is not limited to, a DCB (Direct Copper Bonding) substrate or an AMB (Active Metal Brazing) substrate.

[0019] The insulating substrate 200 may be a ceramic substrate formed from a ceramic material such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), or a composite material of aluminum oxide (Al2O3) and zirconium oxide (ZrO2). The insulating substrate 200 may be a substrate formed by molding an insulating resin such as epoxy resin into a sheet, a substrate formed by impregnating a base material such as glass fiber with an insulating resin, or a substrate formed by coating the surface of a flat metal core with an insulating resin.

[0020] Conductive patterns 201 to 207 arranged on the upper surface of insulating substrate 200 are used as wiring in electronic circuits such as an inverter circuit formed within semiconductor module 1. Heat dissipation pattern 208 arranged on the lower surface of insulating substrate 200 is used as a thermally conductive member that conducts heat generated by semiconductor elements 3 to heat sink 10 during operation of semiconductor module 1. Conductive patterns 201 to 207 and heat dissipation pattern 208 are formed from, for example, a metal plate or metal foil made of copper, aluminum, or the like.

[0021] Wiring board 2 is placed on the upper surface of heat sink 10 together with case 8. Case 8 includes a frame-shaped insulating member 800 with open ends on the upper and lower surfaces, and multiple terminals 801-807 integrated with insulating member 800. When placed on the upper surface of heat sink 10, insulating member 800 of case 8 can accommodate wiring board 2, semiconductor element 3, semiconductor element 4, wiring members 5, 6, 7, etc., and define a space that can be filled with a sealing material to seal them. Wiring board 2A and wiring board 2B may be integrated. Heat dissipation pattern 208 of wiring board 2 is connected to the upper surface of heat sink 10 in close contact with it using a bonding material such as solder, or a thermally conductive material such as thermal grease or thermal compound (not shown). Heat sink 10 may be a metal plate made of, for example, copper or aluminum. Heat sink 10 may have multiple fins on its lower surface. Heat sink 10 may be a part of cooler 11 or a component connected to cooler 11. That is, the cooler 11 is an optional component in the semiconductor module 1 of this embodiment.

[0022] Terminals 801-807 of case 8 are broadly divided into main terminals 801-803 and control terminals 804-807. The main terminals 801-803 are connected to electrodes through which main current flows in switching elements such as IGBT elements. In the case of semiconductor module 1 having an inverter circuit formed therein as illustrated in FIG. 4, first main terminal 801 is a P-IN terminal connected to the positive electrode of a DC power supply and connected to the collector electrode of semiconductor element (IGBT element) 3 arranged on the upper surface of wiring board 2A. Second main terminal 802 is an N-IN terminal connected to the negative electrode of a DC power supply and connected to the emitter electrode of semiconductor element (IGBT element) 3 arranged on the upper surface of wiring board 2B. Third main terminal 803 is an OUT terminal connected to a load that consumes AC converted from DC by semiconductor module 1 and connected to the emitter electrode of semiconductor element 3 arranged on the upper surface of wiring board 2A and the collector electrode of semiconductor element 3 arranged on the upper surface of wiring board 2B. Control terminal 804 is connected to the gate electrode of semiconductor element 3 arranged on the upper surface of wiring board 2A, and control terminal 805 is connected to the gate electrode of semiconductor element 3 arranged on the upper surface of wiring board 2B. Control terminal 806 is connected to the emitter electrode of semiconductor element 3 arranged on the upper surface of wiring board 2A, and control terminal 807 is connected to the emitter electrode of semiconductor element 3 arranged on the upper surface of wiring board 2B. Control terminals 806 and 807 are terminals for connecting the emitter electrode of semiconductor element 3 to gate drive circuit 12 (see FIG. 4), which is connected to the gate electrode of semiconductor element 3, and are also called auxiliary emitter terminals, sense emitter terminals, emitter sense terminals, etc. Gate drive circuit 12 is a circuit that generates control signals that control the on / off of the switching element of semiconductor element 3 using the emitter potential input via control terminals 806 and 807 as ground and applies the control signals to the gate electrode of semiconductor element 3. Control signals for semiconductor elements 3A-3C arranged on the upper surface of wiring board 2A are generated based on the potential of control terminal 806, and control signals for semiconductor elements 3D-3F arranged on the upper surface of wiring board 2B are generated based on the potential of control terminal 807. The gate drive circuits connected to the gate electrodes of semiconductor elements 3A-3C and the gate drive circuits connected to the gate electrodes of semiconductor elements 3D-3E may be formed in separate elements or may be formed in a single element.Terminals 801 to 807 are formed integrally with insulating member 800, and have outer terminal portions that extend to the outside of semiconductor module 1, and inner terminal portions that are exposed to the space in which wiring board 2 and the like are disposed.

[0023] Semiconductor elements 3A to 3C, which are switching elements, and semiconductor elements 4A to 4C, which are diode elements, are arranged on the upper surface of wiring board 2A. As illustrated in Fig. 4, semiconductor elements 3A to 3C are connected in parallel between first main terminal 801 and third main terminal 803 of case 8, and semiconductor elements 4A to 4C are connected in anti-parallel to semiconductor elements 3A to 3C.

[0024] Semiconductor elements 3A-3C are disposed on conductor pattern 201A of wiring board 2A with the surface on which the collector electrode is provided facing downward and the surface on which the emitter electrode and gate electrode are provided facing upward, and the collector electrode and conductor pattern 201A are bonded together with a bonding material (not shown) such as solder. In this case, semiconductor elements 4A-4C are disposed on conductor pattern 201A with the surface on which the cathode electrode is provided facing downward and the surface on which the anode electrode is provided facing upward, and the cathode electrode and conductor pattern 201A are bonded together with a bonding material (not shown) such as solder. The bonding material bonding the collector electrode of semiconductor element 3 to conductor pattern 201 is an example of a first wiring member connecting a first main electrode of semiconductor element 3 to a first conductor pattern of wiring board 2.

[0025] Conductive pattern 201A of wiring board 2A is connected to first main terminal 801 via wiring member 51. The emitter electrodes of semiconductor elements 3A to 3C are connected to the anode electrodes of semiconductor elements 4A to 4C via wiring member 52, respectively, and are connected to conductor pattern 202A of wiring board 2A via wiring member 53. Conductive pattern 202A is connected to third main terminal 803 via wiring member 54, conductor pattern 201B of wiring board 2B, and wiring member 55. The gate electrodes of semiconductor elements 3A to 3C are connected to conductor pattern 203A of wiring board 2A via wiring member 61. Conductive pattern 203A is connected to control terminal 804 via wiring member 62, conductor pattern 205B of wiring board 2B, and wiring member 63. Furthermore, conductor pattern 202A of wiring board 2A is connected to conductor pattern 204A of wiring board 2A via wiring member 71. Conductive pattern 204A is connected to control terminal (auxiliary emitter terminal) 806 via wiring member 72, conductive pattern 206B of wiring board 2B, and wiring member 73. Wiring member 53 connecting the emitter electrode of semiconductor element 3 and conductive pattern 202 is an example of a second wiring member connecting the second main electrode of semiconductor element 3 and the second conductive pattern of wiring board 2. Wiring member 71 connecting conductive pattern 202 and conductive pattern 204 of wiring board 2 is an example of a third wiring member connecting the second conductive pattern of wiring board 2 to a third terminal.

[0026] Semiconductor elements 3D to 3F, which are switching elements, and semiconductor elements 4D to 4F, which are diode elements, are arranged on the upper surface of wiring board 2B. As illustrated in Fig. 4, semiconductor elements 3D to 3F are connected in parallel between third main terminal 803 and second main terminal 802 of case 8, and semiconductor elements 4D to 4F are connected in anti-parallel to semiconductor elements 3D to 3F.

[0027] Semiconductor elements 3D to 3F are arranged on conductor pattern 201B of wiring board 2B with the surface on which the collector electrodes are provided facing downward and the surface on which emitter electrode 301 and gate electrode 302 are provided facing upward (see FIG. 3), and the collector electrodes and conductor pattern 201B are joined together with a bonding material (not shown) such as solder. In this case, semiconductor elements 4D to 4F are arranged on conductor pattern 201B with the surface on which the cathode electrodes are provided facing downward and the surface on which the anode electrodes are provided facing upward, and the cathode electrodes and conductor pattern 201B are joined together with a bonding material (not shown) such as solder.

[0028] Conductive pattern 201B of wiring board 2B is connected to third main terminal 803 by wiring member 55. Emitter electrodes 301 of semiconductor elements 3D to 3F are connected to anode electrodes of semiconductor elements 4A to 4C by wiring member 56, respectively, and are connected to conductor pattern 202B of wiring board 2B by wiring member 57. Conductive pattern 202B is connected to second main terminal 802 via wiring member 58, conductor pattern 205A of wiring board 2A, and wiring member 59. Gate electrodes 302 of semiconductor elements 3D to 3F are each connected to conductor pattern 203B of wiring board 2B by wiring member 64. Conductive pattern 203B is connected to control terminal 805 via wiring member 65, conductor pattern 206A of wiring board 2A, and wiring member 66. Furthermore, conductor pattern 202B of wiring board 2B is connected to conductor pattern 204B of wiring board 2B by wiring member 74. Conductive pattern 204B is connected to control terminal (auxiliary emitter terminal) 807 via wiring member 75, conductor pattern 207A of wiring board 2A, and wiring member 76.

[0029] The wiring members 51-59, wiring members 61-66, and wiring members 71-76 of the semiconductor module 1 may be bonding wires (thin metal wires). In the following description, the wiring members 51-59, wiring members 61-66, and wiring members 71-76 are also referred to as bonding wires 51-59, bonding wires 61-66, and bonding wires 71-76. For example, in the semiconductor module 1, as shown in FIG. 3 , the emitter electrode 301 of each semiconductor element 3 is connected to the anode electrode of the semiconductor element 4 by four bonding wires 56 and to the conductor pattern 202B of the wiring board 2B by four bonding wires 57. In the semiconductor module 1 of this embodiment, the conductor pattern 202B and the conductor pattern 204B connected to the control terminal (auxiliary emitter terminal) 807 are connected to the emitter electrodes 301 of the semiconductor elements 3D-3F connected in parallel by separate bonding wires 74D-74F. Furthermore, in the semiconductor module 1 of this embodiment, the length of the wiring section of the auxiliary emitter wiring that is common to the main current path is changed depending on the length of the auxiliary emitter wiring from the emitter electrode 301 to the control terminal (auxiliary emitter terminal) 807, which differs for each of the semiconductor elements 3D to 3F. Specifically, as illustrated in FIG. 3, the longer the auxiliary emitter wiring, the shorter the wiring section that is common to the main current path. Note that FIG. 3 illustrates only the auxiliary emitter wiring for the semiconductor elements 3D to 3F that are connected in parallel between the third main terminal 803 and the second main terminal 802. The auxiliary emitter wiring for the semiconductor elements 3A to 3C that are connected in parallel between the first main terminal 801 and the third main terminal 803 may have the same configuration as the auxiliary emitter wiring for the semiconductor elements 3D to 3F.

[0030] The length of the auxiliary emitter wiring is expressed as the sum of the length of bonding wire 57 connecting emitter electrode 301 of semiconductor element 3 to conductor pattern 202B of wiring board 2B, the length of bonding wire 74 connecting conductor pattern 202B to conductor pattern 204B, the distance from the connection point of bonding wire 57 on conductor pattern 202B to the connection point of bonding wire 74, and the distance from the connection point of bonding wire 57 on conductor pattern 204B to control terminal 807.

[0031] In the example of FIG. 3, the lengths S0 of the bonding wires 57D to 57F connected to each of the emitter electrodes 301 of the semiconductor elements 3D to 3E are substantially the same, and the distance S1 from the connection point K0 on the conductor pattern 202B side of the bonding wires 57D to 57F to the connection point K4 on the conductor pattern 204B side of the bonding wires 74D to 74F is substantially the same in a plan view. The "connection point" in this specification intends a representative point within the region where the conductor pattern of the wiring board 2 and the third wiring member are connected. Also, in the example of FIG. 3, the distance S21 from the connection point K4 on the conductor pattern 204B side of the bonding wire 74D to the control terminal 807, the distance S22 from the connection point K4 on the conductor pattern 204B side of the bonding wire 74E to the control terminal 807, and the distance S23 from the connection point K4 on the conductor pattern 204B side of the bonding wire 74F to the control terminal 807 are in the relationship of S23 > S22 > S21. In such a case, as illustrated in FIG. 3, the relationship of the magnitudes of the distances G1 from the connection point K0 of the bonding wire 57D to the connection point K1 of the bonding wire 74D, the distance G2 from the connection point K0 of the bonding wire 57E to the connection point K2 of the bonding wire 74E, and the distance G3 from the connection point K0 of the bonding wire 57F to the connection point K3 of the bonding wire 74F on the conductor pattern 202B is made to be G3 < G2 < G1. By doing so, for example, it becomes easy to equalize the voltage drop in the section from the connection point K5 of the bonding wire 75 to the emitter electrode 301 in the conductor pattern 204B of the wiring board 2B among the auxiliary emitter wirings of the semiconductor elements 3D to 3F connected in parallel.

[0032] FIG. 5A is an equivalent circuit diagram for explaining an example of the inductance of the auxiliary emitter wiring in a semiconductor module according to an embodiment, and FIG. 5B is a graph for explaining an example of the switching operation in a semiconductor module according to an embodiment.

[0033] Referring to FIGS. 1 to 4, the wiring for the auxiliary emitter with respect to the switching elements (semiconductor elements) 3D to 3F in the semiconductor module 1 described above can be represented as shown in the equivalent circuit diagram of FIG. 5A. In FIG. 5A, the white circles (○) with "E" attached correspond to the connection points E between the emitter electrodes 301 of the semiconductor elements 3D to 3F illustrated in FIG. 3 and the bonding wires 57D to 57F. Also, the connection points K1 to K3 and the connection point K5 in FIG. 5A correspond to the connection points K1 to K3 and the connection point K5 in FIG. 3.

[0034] In the circuit diagram of FIG. 5A, the magnitude relationship of the inductances L1 of the section from the connection point E to the connection point K1 of the switching element 3D, the inductance L2 of the section from the connection point E to the connection point K2 of the switching element 3E, and the inductance L3 of the section from the connection point E to the connection point K3 of the switching element 3F coincides with the magnitude relationship of the lengths of the respective sections in the wiring for the auxiliary emitter, and the relationship is L3 < L2 < L1. Similarly, the magnitude relationship of the inductances L4 to L6 of the sections from each of the connection points K1 to K3 to the connection point K5 coincides with the magnitude relationship of the lengths of the respective sections in the wiring for the auxiliary emitter, and the relationship is L6 > L5 > L4. On the other hand, although the magnitude relationship of the inductance of the entire wiring for the auxiliary emitter is (L3 + L6) > (L2 + L5) > (L1 + L4), since the main current and the time change of the main current are larger than the current flowing through the single section (section where the main current does not flow) in the wiring for the auxiliary emitter, from the perspective of voltage drop, the influence of the inductances L1, L2, L3 is larger than that of the inductances L4, L5, L6. Therefore, by adjusting the positions of the connection points of the bonding wires 74D to 74F with the conductor pattern 202B of the wiring board 2B and the positions of the connection points with the conductor pattern 204B, it is possible to easily equalize the voltage drops of the wiring for the auxiliary emitter with respect to each of the switching elements 3D to 3F.

[0035] Furthermore, by equalizing the voltage drop across the auxiliary emitter wiring for each of the switching elements 3D to 3F, it is possible to reduce variations in switching speed, switching loss, and the like among the switching elements 3D to 3F connected in parallel. For example, Fig. 5B schematically shows the waveforms of the collector current Ic and the collector-emitter voltage Vce when the semiconductor elements 3D and 3F are turned on, which are associated with the switching speed and switching loss in a conventional configuration. In the semiconductor module 1 of this embodiment, the difference between the waveform of the collector current Ic of the semiconductor element 3D and the waveform of the collector current Ic of the semiconductor element 3F, and the difference between the waveform of the collector-emitter voltage Vce of the semiconductor element 3D and the waveform of the collector-emitter voltage Vce of the semiconductor element 3F are smaller than the differences illustrated in Fig. 5B. Furthermore, the waveform of the collector current Ic and the waveform of the collector-emitter voltage Vce of the semiconductor element 3E also become less different from the waveforms of the collector current Ic and the collector-emitter voltage Vce of the semiconductor elements 3D and 3F. That is, in the semiconductor module 1 of this embodiment, it is possible to suppress variations in heat generation among the switching elements (semiconductor elements) 3D to 3F, and it is possible to improve the reliability of the semiconductor module 1.

[0036] For example, in the semiconductor devices (semiconductor modules) of Patent Documents 3 and 4, a conductor pattern corresponding to the conductor pattern 204B illustrated in FIG. 3, which is part of the auxiliary emitter wiring and through which no main current flows, is directly connected to the emitter electrode of the semiconductor element by a bonding wire. That is, in the semiconductor devices of Patent Documents 3 and 4, the auxiliary emitter wiring does not include a section through which the main current flows. In such semiconductor devices, the inductance of the auxiliary emitter wiring for each of the parallel-connected semiconductor elements varies, for example, as shown in FIG. 5A for inductances L4 to L6 in the section through which the main current does not flow. This results in a variation in the voltage drop across the auxiliary emitter wiring. That is, in the semiconductor devices of Patent Documents 3 and 4, the voltage drop across the auxiliary emitter wiring for each of the parallel-connected semiconductor elements cannot be equalized by using the inductance in the section through which the main current flows, as in the semiconductor module 1 of the present embodiment. Therefore, in the semiconductor devices of Patent Documents 3 and 4, it is difficult to reduce variations in switching speed, switching loss, and the like between the parallel-connected semiconductor elements.

[0037] Furthermore, in the semiconductor device (semiconductor module) of Patent Document 1, the conductor patterns corresponding to the conductor patterns 202B and 204B illustrated in FIG. 3 are connected by a single bonding wire. In such a semiconductor device, variations occur, such as the inductances L1 to L3 in the section where the main current flows, as shown in FIG. 5A, resulting in variations in voltage drop. That is, in the semiconductor device of Patent Document 1, the voltage drop across both ends of the auxiliary emitter wiring for each of the parallel-connected semiconductor elements cannot be equalized by using a combination of inductances in the section where the main current flows and inductances in the section where the main current does not flow, as in the semiconductor module 1 of the present embodiment. For this reason, it is difficult for the semiconductor device of Patent Document 1 to reduce variations in switching speed, switching loss, and the like between the parallel-connected semiconductor elements. Furthermore, in the semiconductor device of Patent Document 2, two of the configurations of Patent Document 1 are connected in parallel, and similarly, the configuration does not use the inductance in the section where the main current flows to equalize the voltage drop.

[0038] Fig. 6 is a partially enlarged plan view illustrating a conventional example of auxiliary emitter wiring in a semiconductor module in which multiple semiconductor elements are connected in parallel. Fig. 7A is an equivalent circuit diagram illustrating an example of inductance of the auxiliary emitter wiring in the semiconductor module of Fig. 6, and Fig. 7B is a graph illustrating an example of switching operation in the semiconductor module of Fig. 6. Fig. 8 is a partially enlarged plan view illustrating a modified example of the semiconductor module according to an embodiment.

[0039] Similar to semiconductor module 1 of the present embodiment, three semiconductor elements (switching elements) 3D-3F illustrated in FIG. 6 are connected in parallel between third main terminal 803 and second main terminal 802 (see FIG. 7A). Emitter electrodes 301 of semiconductor elements 3D-3F arranged on conductor pattern 201B of wiring board 2 are connected to conductor pattern 202B of wiring board 2. However, emitter electrodes 301 of semiconductor elements 3D and 3F are directly connected to conductor pattern 202B by bonding wires 57D and 57F, whereas emitter electrode 301 of semiconductor element 3E is connected to conductor pattern 202B via the anode electrode of diode element (semiconductor element) 4 connected in anti-parallel. In the semiconductor module illustrated in FIG. 6, conductor pattern 202B and conductor pattern 204B, which is part of the auxiliary emitter wiring and is connected to a control terminal (auxiliary emitter terminal) not shown, are connected by one bonding wire 74. That is, the auxiliary emitter wiring of the semiconductor module illustrated in FIG. 6 is similar to the auxiliary emitter wiring of the semiconductor device of Patent Document 1, for example.

[0040] When focusing on inductance, the auxiliary emitter wiring in the semiconductor module illustrated in Fig. 6 can be expressed as shown in the equivalent circuit diagram of Fig. 7A. In Fig. 7A, the white circle (○) with an "E" attached corresponds to connection point E between emitter electrode 301 of semiconductor elements 3D, 3E, and 3F illustrated in Fig. 6 and bonding wires 57D, 56, and 57F. Furthermore, connection point KK6 in Fig. 7A corresponds to connection point K6 of the bonding wire in Fig. 6.

[0041] 6, the length from connection point E to connection point K01 on the auxiliary emitter wiring for semiconductor element 3D is substantially the same as the length from connection point E to connection point K03 on the auxiliary emitter wiring for semiconductor element 3F. However, the length from connection point E to connection point K02 on the auxiliary emitter wiring for semiconductor element 3E is longer than the length between the connection points on the auxiliary emitter wiring for semiconductor elements 3D and 3F. Furthermore, compared with the distance from connection point K01 to connection point K6 on the auxiliary emitter wiring for semiconductor element 3D, the distance from connection point K02 to connection point K6 on the auxiliary emitter wiring for semiconductor element 3E and the distance from connection point K03 to connection point K6 on the auxiliary emitter wiring for semiconductor element 3F are longer. In such a semiconductor module, the inductance variation in the section from connection point E to connection point K6, through which the main current flows in the auxiliary emitter wiring for each of the semiconductor elements 3D to 3F, becomes even greater, as shown by inductances L8 to L10 in FIG. 7A. That is, the voltage drop variation in the auxiliary emitter wiring for each of the semiconductor elements (switching elements) 3D to 3F becomes greater. In this case, as shown in FIG. 7B, the variation in switching speed, switching loss, and the like among the three semiconductor elements 3D to 3F connected in parallel tends to become even greater. FIG. 7B schematically shows the waveforms of the collector current Ic and the collector-emitter voltage Vce when the semiconductor elements 3D to 3F are turned on, which are associated with the switching speed and switching loss.

[0042] 8, for example, conductor pattern 202B of wiring board 2B is connected to conductor pattern 204 by separate bonding wires 74D-74F for each of emitter electrodes 301 of three semiconductor elements 3D-3F connected in parallel. In this case, as described above, the longer the auxiliary emitter wiring, the shorter the wiring section of the auxiliary emitter wiring that is common to the main current path. This reduces the variation in voltage drop between the auxiliary emitter wiring for each of the three semiconductor elements (switching elements) 3D-3F connected in parallel, and reduces the variation in switching speed, switching loss, etc. between semiconductor elements 3D-3F. Furthermore, as illustrated in Figure 8, when the dimensions of semiconductor element 3, which is a switching element, and semiconductor element 4, which is a diode element, are different in plan view, staggering semiconductor elements 3 and 4 allows semiconductor elements 3 and 4 to be arranged more densely than when semiconductor elements 3 are arranged so that the distances to conductor pattern 202B are the same (see Figure 3), which is advantageous for miniaturizing semiconductor module 1, etc.

[0043] The number of semiconductor elements (switching elements) 3 connected in parallel in the semiconductor module 1 is not limited to three, but may be two, four, or more. The switching elements are not limited to IGBT elements, but may be, for example, power MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), BJTs (Bipolar Junction Transistors), etc. When the switching elements are power MOSFETs, auxiliary source wiring connected to the source electrodes of the MOSFETs is provided as wiring corresponding to the auxiliary emitter wiring. The diode elements connected in anti-parallel to the switching elements may be, for example, SBDs (Schottky Barrier Diodes), JBS (Junction Barrier Schottky) diodes, MPS (Merged PN Schottky) diodes, PN diodes, etc. The semiconductor module 1 may use RC (Reverse Conducting)-IGBT elements that combine the functions of a switching element and a diode element, instead of the semiconductor elements 3 serving as switching elements and the semiconductor elements 4 serving as diode elements. The semiconductor module 1 may also include a gate drive circuit 12 (see FIG. 4 ).

[0044] The positions of the connection points of the wiring members 71 and 74 used as part of the auxiliary emitter wiring in the semiconductor module 1 on the side of the conductor pattern 202 through which the main current flows may be any position where the influence of the potential of the emitter electrode 301 of the semiconductor element 3 associated with that wiring member is sufficiently greater than the influence of the potential of the emitter electrodes 301 of other semiconductor elements (in other words, the influence of the potential of the emitter electrodes 301 of other semiconductor elements is sufficiently small), and are not limited to a specific position. Furthermore, for example, the extension direction of the wiring members (bonding wires) 71 and 74 in a plan view may be different from the extension direction of the wiring members 53 and 57. Furthermore, the extension directions of the bonding wires 74D, 74E, and 74F in a plan view may not be the same. The wiring members 71 and 74 used as part of the auxiliary emitter wiring in the semiconductor module 1 may be directly connected to control terminals (auxiliary emitter terminals) 806 and 807 provided on the case 8 without going through the conductor pattern of the wiring board 2.

[0045] Some of the wiring members in semiconductor module 1 may be made of metal plates such as copper plates instead of bonding wires. For example, wiring member 51 connecting first main terminal 801 and conductor pattern 201A of wiring board 2A, wiring member 53 connecting the emitter electrodes of semiconductor elements 3A to 3C and conductor pattern 202A of wiring board 2A, wiring member 56 connecting the emitter electrodes of semiconductor elements 3D to 3F and conductor pattern 202B of wiring board 2B, etc. may be metal plates called leads, lead frames, etc. Wiring board 2 in semiconductor module 1 may be one in which heat dissipation pattern 208 is omitted, for example.

[0046] Although the semiconductor module 1 of the above-described embodiment is not limited to a specific use, the semiconductor module 1 equipped with the cooler 11 is particularly suitable for use in high-temperature environments. For example, the semiconductor module 1 of the above-described embodiment can be applied to a power conversion device such as an inverter device for an in-vehicle motor. A vehicle to which the semiconductor module 1 according to the present invention is applied will be described with reference to FIG. 9.

[0047] Fig. 9 is a schematic plan view showing an example of a vehicle to which a semiconductor module according to the present invention is applied. Vehicle 1501 shown in Fig. 9 is, for example, a four-wheeled vehicle having four wheels 1502. Vehicle 1501 may be, for example, an electric vehicle in which the wheels are driven by a motor or the like, or a hybrid vehicle that uses power from an internal combustion engine in addition to a motor. Furthermore, vehicles to which semiconductor module 1 is applied are not limited to four-wheeled vehicles, and may also be motorcycles, railway vehicles, etc.

[0048] Vehicle 1501 includes a drive unit 1503 that applies power to wheels 1502, and a control device 1504 that controls drive unit 1503. Drive unit 1503 may be configured with at least one of an engine, a motor, or a hybrid of an engine and a motor, for example.

[0049] The control device 1504 controls (e.g., controls power) the drive unit 1503. The control device 1504 includes a semiconductor module 1 including the cooler 11 according to the embodiment described above. The semiconductor module 1 can be configured to control power to the drive unit 1503.

[0050] The semiconductor module 1 according to the above-described embodiment may be applied to industrial power conversion devices, such as inverter devices for driving motors in elevators, escalators, building air conditioning systems, etc. Furthermore, the circuit formed in the semiconductor module 1 is not limited to the half-bridge inverter circuit illustrated in FIG. 4 . The circuit formed in the semiconductor module 1 may have, for example, only the upper arm (the circuit portion between the main terminal 801 and the main terminal 803) or the lower arm (the circuit portion between the main terminal 803 and the main terminal 802) of the half-bridge circuit in FIG. 4 , or may have multiple (e.g., three) half-bridge inverter circuits. The circuit formed in the semiconductor module 1 may be a full-bridge inverter circuit. Furthermore, the circuit formed in the semiconductor module 1 is not limited to a power conversion circuit that converts direct current to alternating current, and may be another circuit.

[0051] The features of the above-described embodiment will be summarized below. The semiconductor module according to the above-described embodiment includes a wiring board having a first conductor pattern and a second conductor pattern arranged on one surface of an insulating substrate, a plurality of semiconductor elements arranged on the first conductor pattern of the wiring board, a first wiring member connecting each of the first main electrodes of the plurality of semiconductor elements to the first conductor pattern, a second wiring member connecting each of the second main electrodes of the plurality of semiconductor elements to the second conductor pattern, a first terminal connected to the first main electrodes of the plurality of semiconductor elements via the first conductor pattern and through which a main current flows, a second terminal connected to the second main electrodes of the plurality of semiconductor elements via the second conductor pattern and through which a main current flows, and a third terminal connected to the second conductor pattern via a third wiring member. Each of the plurality of semiconductor elements includes a switching element that controls the current flowing between the first main electrode and the second main electrode, and the third wiring member includes a plurality of wiring members corresponding to each of the plurality of semiconductor elements, and the distance from the connection point of the plurality of wiring members on the second conductor pattern to the connection point of the second wiring member varies depending on the distance from a predetermined position on the third terminal to the connection point of the second wiring member on the second main electrodes of the plurality of semiconductor elements.

[0052] In the semiconductor module according to the above embodiment, the plurality of semiconductor elements include a first semiconductor element and a second semiconductor element, and when the distance from the predetermined position in the third terminal portion to the connection point of the second wiring member on the second main electrode of the first semiconductor element is longer than the distance from the predetermined position in the third terminal portion to the connection point of the second wiring member on the second main electrode of the second semiconductor element, the distance on the second conductive pattern from the connection point of the wiring member of the third wiring member associated with the first semiconductor element to the connection point of the second wiring member connected to the second main electrode of the first semiconductor element is shorter than the distance from the connection point of the wiring member of the third wiring member associated with the second semiconductor element to the connection point of the second wiring member connected to the second main electrode of the second semiconductor element.

[0053] In the semiconductor module according to the above embodiment, the third terminal is connected to a control circuit that generates control signals to be applied to the control electrodes of the plurality of semiconductor elements.

[0054] In the semiconductor module according to the above embodiment, each of the plurality of semiconductor elements includes the switching element and a diode element connected in anti-parallel to the switching element.

[0055] In the semiconductor module according to the above embodiment, the semiconductor module further comprises a second plurality of semiconductor elements connected to each of the plurality of semiconductor elements, and each of the second plurality of semiconductor elements includes a diode element connected in anti-parallel to the switching element in each of the plurality of semiconductor elements.

[0056] In the semiconductor module according to the above embodiment, the second wiring member includes a wiring member that connects the second main electrode of one of the second plurality of semiconductor elements to the second conductor pattern via an electrode of the semiconductor element.

[0057] In the semiconductor module according to the above embodiment, the plurality of semiconductor elements are arranged on the first conductor pattern so that the lengths from the connection points with the second main electrode on the second wiring member to the connection points with the second conductor pattern are substantially the same.

[0058] In the semiconductor module according to the above embodiment, the first wiring member is a bonding material, and the second wiring member and the third wiring member are bonding wires.

[0059] In the semiconductor module according to the above embodiment, the switching element is an IGBT (Insulated Gate Bipolar Transistor) element, the first main electrode is a collector electrode of the IGBT element, and the second main electrode is an emitter electrode of the IGBT element.

[0060] In the semiconductor module according to the above embodiment, the plurality of semiconductor elements are arranged so that the distances to the second conductor pattern are the same.

[0061] The semiconductor module according to the above embodiment further includes a cooler connected to the wiring board and disposed in a direction opposite to the direction in which the semiconductor elements are disposed on the wiring board.

[0062] The vehicle according to the above-described embodiment includes the semiconductor module according to the above-described embodiment.

[0063] The present invention is not limited to the above-described embodiments, and may be variously modified, substituted, or altered without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea. [Industrial Applicability]

[0064] As described above, the present invention has the effect of reducing the variation in switching operation among multiple switching elements connected in parallel in a semiconductor module, and suppressing a decrease in the operational reliability of the semiconductor module due to variation in heat generation among the switching elements, and is particularly useful for industrial or vehicular semiconductor modules used as power conversion devices. [Explanation of symbols]

[0065] 1. Semiconductor module 2, 2A, 2B wiring board 200, 200A, 200B insulating substrate 201, 201A, 201B, 202A, 202B, 204B Conductor patterns 3A~3F Semiconductor elements (switching elements) 301 Emitter electrode 302 Gate electrode 4A~4F Semiconductor elements (diode elements) 51~59, 61~66, 71~76 Wiring parts 8 cases 801~803 Main terminal 806, 807 Control terminals (auxiliary emitter terminals) 10 Heat sink 11 Cooler 12 Gate drive circuit

Claims

1. a wiring board in which a first conductor pattern and a second conductor pattern are arranged on one surface of an insulating substrate; a plurality of semiconductor elements arranged on the first conductor pattern of the wiring board; a first wiring member connecting each of the first main electrodes of the plurality of semiconductor elements to the first conductor pattern; a second wiring member connecting each of the second main electrodes of the plurality of semiconductor elements to the second conductor pattern; a first terminal connected to the first main electrodes of the semiconductor elements via the first conductor pattern and through which a main current flows; a second terminal connected to the second main electrodes of the semiconductor elements via the second conductor pattern and through which a main current flows; a third terminal connected to the second conductor pattern via a third wiring member; each of the plurality of semiconductor elements includes a switching element that controls a current flowing between the first main electrode and the second main electrode; the third wiring member includes a plurality of wiring members each corresponding to one of the plurality of semiconductor elements; The distance from the connection points of the plurality of wiring members on the second conductor pattern to the connection points of the second wiring member varies depending on the distance from a predetermined position on the third terminal to the connection points of the second main electrodes of the plurality of semiconductor elements to the second wiring member. Semiconductor module.

2. the plurality of semiconductor elements include a first semiconductor element and a second semiconductor element; When the distance from the predetermined position on the third terminal portion to the connection point of the second main electrode of a first semiconductor element with the second wiring member is longer than the distance from the predetermined position on the third terminal portion to the connection point of the second main electrode of a second semiconductor element with the second wiring member, the distance on the second conductive pattern from the connection point of the wiring member of the third wiring member associated with the first semiconductor element to the connection point of the second wiring member connected to the second main electrode of the first semiconductor element is shorter than the distance from the connection point of the wiring member of the third wiring member associated with the second semiconductor element to the connection point of the second wiring member connected to the second main electrode of the second semiconductor element. The semiconductor module according to claim 1 .

3. The third terminal is connected to a control circuit that generates a control signal to be applied to the switching element. The semiconductor module according to claim 1 .

4. Each of the plurality of semiconductor elements includes the switching element and a diode element connected in antiparallel to the switching element. The semiconductor module according to claim 3 .

5. a second plurality of semiconductor elements connected to each of the plurality of semiconductor elements; Each of the second plurality of semiconductor elements includes a diode element connected in antiparallel to the switching element in each of the second plurality of semiconductor elements. The semiconductor module according to claim 3 .

6. 6. The semiconductor module according to claim 5, wherein the second wiring member includes a wiring member that connects the second main electrode of one of the second plurality of semiconductor elements to the second conductor pattern via an electrode of the semiconductor element.

7. 2. The semiconductor module according to claim 1, wherein the plurality of semiconductor elements are arranged on the first conductor pattern so that the lengths from the connection points of the second wiring member with the second main electrode to the connection points of the second conductor pattern are substantially the same.

8. 2. The semiconductor module according to claim 1, wherein the first wiring member is a bonding material, and the second wiring member and the third wiring member are bonding wires.

9. 2. The semiconductor module according to claim 1, wherein the switching element is an IGBT (Insulated Gate Bipolar Transistor) element, the first main electrode is a collector electrode of the IGBT element, and the second main electrode is an emitter electrode of the IGBT element.

10. The semiconductor module according to claim 1 , wherein the plurality of semiconductor elements are arranged so that the distances to the second conductor pattern are the same.

11. 11. The semiconductor module according to claim 1, further comprising a cooler connected to said wiring board and arranged in a direction opposite to a direction in which said semiconductor element is arranged on said wiring board.

12. A vehicle comprising the semiconductor module of claim 10.

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