Semiconductor module and vehicle

Abstract

The invention relates to a semiconductor module and a vehicle. The purpose of the present invention is to reduce variations in switching operations among a plurality of switching elements connected in parallel. The semiconductor module includes: a second wiring member that connects each of second main electrodes of a plurality of semiconductor elements connected in parallel to a second conductor pattern 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 having a control electrode 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 corresponding to the plurality of semiconductor elements, respectively. The distance from the connection point of the plurality of wiring members to the connection point of the second wiring member on the second conductor pattern differs in accordance with the distance from the predetermined position of the third terminal to the connection point between the second main electrode and the second wiring member.

Description

Technical Field

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

[0002] Among semiconductor modules used in power conversion devices, some have multiple IGBT (Insulated Gate Bipolar Transistor) elements connected in parallel. Some of these semiconductor modules include a conductive member called an auxiliary emitter, which connects the emitter of the IGBT element to a gate drive circuit connected to the gates of the multiple IGBT elements connected in parallel (e.g., Patent Documents 1 to 4).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2023-167403

[0006] Patent Document 2: International Publication No. 2020 / 054806

[0007] Patent Document 3: International Publication No. 2022 / 059251

[0008] Patent Document 4: International Publication No. 2022 / 264851 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] In a semiconductor module including an auxiliary emitter, uneven switching operations of a plurality of IGBT elements connected in parallel may cause variations in heat generation among the IGBT elements, thereby reducing the reliability of the semiconductor module.

[0011] One object of the present invention is to reduce variations in switching operations among a plurality of switching elements connected in parallel in a semiconductor module.

[0012] Solutions for solving problems

[0013] 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 the first main electrodes of the plurality of semiconductor elements to the first conductor pattern; a second wiring member connecting 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. The third wiring member includes a plurality of wiring members corresponding to the plurality of semiconductor elements. The distances from the connection points of the plurality of wiring members to the connection points of the second wiring member on the second conductor pattern vary depending on the distances from a predetermined position in the third terminal to the connection points of the second main electrodes of the plurality of semiconductor elements with the second wiring member.

[0014] Effects of the Invention

[0015] According to the above-described aspect, it is possible to reduce variations in switching operations among a plurality of switching elements connected in parallel in a semiconductor module. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a top view of a semiconductor module according to one embodiment.

[0017] Figure 2 It is an explanation Figure 1 A cross-sectional view of an example of the structure inside a casing of a semiconductor module.

[0018] Figure 3 It is an explanation Figure 1 A partially enlarged cross-sectional view of a structural example of auxiliary emitter wiring in a semiconductor module.

[0019] Figure 4 is formed in Figure 1 Equivalent circuit diagram of the inverter circuit of the semiconductor module.

[0020] Figure 5A is an equivalent circuit diagram illustrating an example of the inductance of the auxiliary emitter wiring in the semiconductor module according to one embodiment. Figure 5B This is a graph illustrating an example of a switching operation in a semiconductor module according to an embodiment.

[0021] Figure 6 This 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.

[0022] Figure 7A It is an explanation Figure 6 An equivalent circuit diagram showing an example of the inductance of the auxiliary emitter wiring in a semiconductor module is shown in FIG. Figure 7B It is an explanation Figure 6 A diagram showing an example of switching action in a semiconductor module.

[0023] Figure 8 This is a partially enlarged plan view illustrating a modified example of the semiconductor module according to one embodiment.

[0024] Figure 9 1 is a schematic plan view showing an example of a vehicle to which the semiconductor module of the present invention is applied.

[0025] Description of Reference Numerals

[0026] 1. Semiconductor module; 2. 2A, 2B, wiring board; 200, 200A, 200B, insulating substrate; 201, 201A, 201B, 202A, 202B, 204B, conductor pattern; 3A to 3F, semiconductor element (switching element); 301, emitter; 302, gate electrode; 4A to 4F, semiconductor element (diode element); 51 to 59, 61 to 66, 71 to 76, wiring member; 8. housing; 801 to 803, main terminals; 806, 807, control terminals (auxiliary emitter terminals); 10. heat sink; 11. cooler; 12. gate drive circuit. DETAILED DESCRIPTION

[0027] The following describes embodiments of the present invention in detail with reference to the accompanying drawings. A "semiconductor module" in the following description is a semiconductor element (sometimes referred to as a semiconductor chip or chip) sealed with an insulating material. A semiconductor module may also be referred to as a "semiconductor device."

[0028] The X-axis, Y-axis, and Z-axis in the referenced figures are shown for the purpose of defining the plane and direction of the semiconductor module shown in the figure. The X-axis, Y-axis, and Z-axis are orthogonal to each other, forming 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. In addition, each direction of the X-axis, Y-axis, and Z-axis is labeled "positive side" or "negative side" when associated with the direction of the arrows (positive and negative) of the X-axis, Y-axis, and Z-axis shown in the figure.

[0029] In this specification, the Z direction is sometimes referred to as the up-down direction. In this specification, "up" or "above" means the positive Z-direction relative to a reference surface, component, or location, and "down" or "below" means the negative Z-direction relative to a reference surface, component, or location. For example, when "component B is disposed on component A," component B is disposed on the positive Z-direction side as viewed from component A. Furthermore, when "the upper surface of component A" is described, this surface includes the end portion of component A that is located on the positive Z-direction side and faces the positive Z-direction side. These directions and the surfaces associated with these directions are used for convenience of description. Depending on the mounting posture of the semiconductor module, the corresponding relationships with the X-axis, Y-axis, and Z-axis directions may vary. For example, in this specification, the surface of a semiconductor element that faces the wiring board is referred to as the lower surface, and the surface opposite the lower surface is referred to as the upper surface. However, this is not limiting; the surface facing the wiring board may also be referred to as the upper surface, and the surface opposite the lower surface may also be referred to as the lower surface.

[0030] The aspect ratios and size relationships of the components in the figures are schematic representations only and may not necessarily correspond to the relationships in an actual manufactured semiconductor module. For ease of explanation, the size relationships of the components may be exaggerated, and the appearance of components used in actual semiconductor modules may differ. Furthermore, for ease of explanation, some of the cross-sectional views depict the cross-sectional structure of the semiconductor module along imaginary cutting lines that cannot be accurately depicted in the top view.

[0031] Throughout this specification, terms such as "not shown," "not illustrated," and "not shown" mean that specific reference numerals and lead lines are not used to clearly indicate which portion of the figure the component in question represents. For example, "first main electrode not shown" means that the portion representing the first main electrode (e.g., a pattern or line) is not shown in the figure, and that there are no reference numerals or lead lines that clearly indicate the portion corresponding to the first main electrode in the figure. Furthermore, underlined reference numerals in the figures represent the entire component, including multiple portions distinguished by multiple reference numerals.

[0032] The semiconductor modules described below can be used in power conversion devices such as inverters for industrial or electrical applications (e.g., automotive motors). Therefore, detailed descriptions of structures, functions, operations, and manufacturing methods that are identical or similar to those of known semiconductor modules will be omitted.

[0033] Figure 1 This is a top view of a semiconductor module according to one embodiment. Figure 2 It is an explanation Figure 1 A cross-sectional view of an example of the structure inside a casing of a semiconductor module. Figure 3It is an explanation Figure 1 A partially enlarged cross-sectional view of a structural example of auxiliary emitter wiring in a semiconductor module. Figure 4 is formed in Figure 1 Equivalent circuit diagram of the inverter circuit of the semiconductor module. Figure 2 A cross-sectional view can be Figure 1 1 is an illustration of a cross-sectional structure of the semiconductor module 1 taken along the dashed-dotted line AA′ in the semiconductor module 1 .

[0034] The semiconductor module 1 of this embodiment includes wiring boards 2A, 2B, semiconductor elements 3A to 3F, 4A to 4F, wiring members 51 to 59, 61 to 66, 71 to 76, a housing 8, a sealing material (not shown), and a heat sink 10. In this specification, when multiple identical components are distinguished, reference numerals are recorded using a combination of a number and a letter following the number. When no distinction is made, only the number is recorded. For example, when referring to a specific semiconductor element among multiple semiconductor elements 3A to 3F, Figure 1 In the reference numeral 3A to 3F, the reference numeral assigned to the specific semiconductor element is described. In other cases, it is simply described as "semiconductor element 3".

[0035] The wiring board 2 is a component mounting member for mounting semiconductor elements 3 and 4, which are sometimes also called semiconductor chips or chips. The semiconductor element 3 is a switching element such as an IGBT (Insulated Gate Bipolar Transistor) element, and the semiconductor element 4 is a diode element such as an FWD (Free Wheeling Diode) element. The wiring board 2, the semiconductor element 3, and the semiconductor element 4 are used to form Figure 4 Circuit components of the half-bridge inverter circuit illustrated in FIG.

[0036] Wiring board 2A includes an insulating substrate 200A, conductor patterns 201A-207A arranged on the upper surface of insulating substrate 200A, and a heat dissipation pattern 208A arranged on the lower surface of insulating substrate 200A. Wiring board 2B includes an insulating substrate 200B, conductor patterns 201B-206B arranged on the upper surface of insulating substrate 200B, and a heat dissipation pattern 208B arranged on the lower surface of insulating substrate 200B. Wiring board 2 can be a DCB (Direct Copper Bonding) substrate or an AMB (Active Metal Brazing) substrate, but is not limited to these substrates.

[0037] The insulating substrate 200 may be a ceramic substrate formed of 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). Alternatively, the insulating substrate 200 may be a substrate formed into a sheet of insulating resin such as epoxy resin, a substrate impregnated with insulating resin into a base material such as glass fiber, or a substrate formed by coating the surface of a flat metal core with insulating resin.

[0038] Conductor patterns 201 to 207 arranged on the upper surface of insulating substrate 200 serve as wiring for electronic circuits such as inverter circuits formed within semiconductor module 1. Heat dissipation pattern 208 arranged on the lower surface of insulating substrate 200 serves as a thermally conductive member that conducts heat generated by semiconductor element 3 to heat sink 10 during operation of semiconductor module 1. Conductor patterns 201 to 207 and heat dissipation pattern 208 are formed of, for example, metal plates or metal foils such as copper and aluminum.

[0039] Wiring board 2 is arranged on the upper surface of heat sink 10 together with housing 8. Housing 8 includes a frame-shaped insulating member 800 with open ends on the upper and lower surfaces, and a plurality of terminals 801 to 807 integrated with insulating member 800. Insulating member 800 of housing 8 can be shaped so as to define a space that can accommodate wiring board 2, semiconductor element 3, semiconductor element 4, wiring members 5, 6, 7, etc., and be filled with a sealing material to seal these components when arranged on the upper surface of heat sink 10. Wiring board 2A and wiring board 2B can also be integrated. The heat dissipation pattern 208 of wiring board 2 is connected to the upper surface of heat sink 10 using a bonding material such as solder, a thermally conductive member such as thermal grease or a thermally conductive compound (not shown) in close contact with the upper surface of heat sink 10. Heat sink 10 can be, for example, a metal plate such as copper or aluminum. Heat sink 10 can also be provided with a plurality of heat dissipation fins on its lower surface. Heat sink 10 can be part of cooler 11 or a component connected to cooler 11. In other words, cooler 11 is an arbitrary structural element in semiconductor module 1 of this embodiment.

[0040] The terminals 801 to 807 of the housing 8 are roughly divided into main terminals 801 to 803 and control terminals 804 to 807. The main terminals 801 to 803 are connected to electrodes through which the main current flows in switching elements such as IGBT elements. Figure 4In the case of the semiconductor module 1 of the inverter circuit illustrated in FIG, first main terminal 801 is a P-IN terminal connected to the positive electrode of the DC power supply and connected to the collector 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 the DC power supply and connected to the emitter 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 the AC converted from DC by semiconductor module 1 and is connected to the emitter of semiconductor element 3 arranged on the upper surface of wiring board 2A and the collector 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. The control terminal 806 is connected to the emitter of the semiconductor element 3 arranged on the upper surface of the wiring board 2A, and the control terminal 807 is connected to the emitter of the semiconductor element 3 arranged on the upper surface of the wiring board 2B. The control terminals 806 and 807 are used to connect the emitter of the semiconductor element 3 to the gate drive circuit 12 connected to the gate electrode of the semiconductor element 3 (see Figure 4 ) terminals are called auxiliary emitter terminals, detection emitter terminals, emitter detection terminals, etc. The gate drive circuit 12 is a circuit that sets the emitter potential input through the control terminals 806 and 807 to ground, generates a control signal for controlling the on / off of the switching element of the semiconductor element 3, and applies it to the gate electrode of the semiconductor element 3. Based on the potential of the control terminal 806, a control signal is generated for the semiconductor elements 3A to 3C arranged on the upper surface of the wiring board 2A, and based on the potential of the control terminal 807, a control signal is generated for the semiconductor elements 3D to 3F arranged on the upper surface of the wiring board 2B. The gate drive circuit connected to the gate electrodes of the semiconductor elements 3A to 3C and the gate drive circuit connected to the gate electrodes of the semiconductor elements 3D to 3E can be formed in different elements or in a single element. The terminals 801 to 807 are formed integrally with the insulating member 800, and have an outer terminal portion extending to the outside of the semiconductor module 1 and an inner terminal portion exposed to the space where the wiring board 2 is arranged.

[0041] On the upper surface of wiring board 2A, semiconductor elements 3A to 3C serving as switching elements and semiconductor elements 4A to 4C serving as diode elements are arranged. Figure 4 In the illustrated example, semiconductor elements 3A to 3C are connected in parallel between the first main terminal 801 and the third main terminal 803 of the housing 8 , and semiconductor elements 4A to 4C are connected in anti-parallel to the semiconductor elements 3A to 3C.

[0042] Semiconductor elements 3A-3C are arranged on conductor pattern 201A of wiring board 2A with the surface provided with the collector electrode as the lower surface and the surface provided with the emitter and gate electrodes as the upper surface. The collector electrode and conductor pattern 201A are joined using a bonding material such as solder (not shown). In this case, semiconductor elements 4A-4C are arranged on conductor pattern 201A with the surface provided with the cathode electrode as the lower surface and the surface provided with the anode electrode as the upper surface. The cathode electrode and conductor pattern 201A are joined using a bonding material such as solder (not shown). The bonding material joining the collector electrode of semiconductor element 3 to conductor pattern 201 is an example of a first wiring member connecting the first main electrode of semiconductor element 3 to the first conductor pattern of wiring board 2.

[0043] Conductor pattern 201A on wiring board 2A is connected to first main terminal 801 via wiring member 51. The emitters of semiconductor elements 3A to 3C are connected to the anodes of semiconductor elements 4A to 4C, respectively, via wiring member 52, and are connected to conductor pattern 202A on wiring board 2A via wiring member 53. Conductor pattern 202A is connected to third main terminal 803 via wiring member 54, conductor pattern 201B on wiring board 2B, and wiring member 55. Gate electrodes of semiconductor elements 3A to 3C are connected to conductor pattern 203A on wiring board 2A, respectively, via wiring member 61. Conductor pattern 203A is connected to control terminal 804 via wiring member 62, conductor pattern 205B on wiring board 2B, and wiring member 63. Furthermore, conductor pattern 202A on wiring board 2A is connected to conductor pattern 204A on wiring board 2A via wiring member 71. Conductor pattern 204A is connected to control terminal (auxiliary emitter terminal) 806 via wiring member 72, conductor pattern 206B of wiring board 2B, and wiring member 73. Wiring member 53 connecting the emitter of semiconductor element 3 to conductor pattern 202 is an example of a second wiring member connecting the second main electrode of semiconductor element 3 to the second conductor pattern of wiring board 2. Wiring member 71 connecting conductor pattern 202 and conductor pattern 204 of wiring board 2 is an example of a third wiring member connecting the second conductor pattern of wiring board 2 to the third terminal.

[0044] On the upper surface of wiring board 2B, semiconductor elements 3D to 3F serving as switching elements and semiconductor elements 4D to 4F serving as diode elements are arranged. Figure 4 In the illustrated example, semiconductor elements 3D to 3F are connected in parallel between the third main terminal 803 and the second main terminal 802 of the case 8 , and semiconductor elements 4D to 4F are connected in anti-parallel to the semiconductor elements 3D to 3F.

[0045] The semiconductor elements 3D to 3F are arranged on the conductor pattern 201B of the wiring board 2B with the surface provided with the collector being the lower surface and the surface provided with the emitter 301 and the gate electrode 302 being the upper surface (see FIG. Figure 3 ), the collector electrode and the conductor pattern 201B are joined using a bonding material such as solder (not shown). In this case, the semiconductor elements 4D to 4F are arranged on the conductor pattern 201B with the surface provided with the cathode being the lower surface and the surface provided with the anode being the upper surface, and the cathode and the conductor pattern 201B are joined using a bonding material such as solder (not shown).

[0046] Conductor pattern 201B on wiring board 2B is connected to third main terminal 803 via wiring member 55. Emitter electrodes 301 of semiconductor elements 3D to 3F are each connected to the anodes of semiconductor elements 4A to 4C via wiring member 56, and are connected to conductor pattern 202B on wiring board 2B via wiring member 57. Conductor pattern 202B is connected to second main terminal 802 via wiring member 58, conductor pattern 205A on wiring board 2A, and wiring member 59. Gate electrodes 302 of semiconductor elements 3D to 3F are each connected to conductor pattern 203B on wiring board 2B via wiring member 64. Conductor pattern 203B is connected to control terminal 805 via wiring member 65, conductor pattern 206A on wiring board 2A, and wiring member 66. Furthermore, conductor pattern 202B on wiring board 2B is connected to conductor pattern 204B on wiring board 2B via wiring member 74. Conductive pattern 204B is connected to control terminal (auxiliary emitter terminal) 807 via wiring member 75 , conductive pattern 207A of wiring board 2A, and wiring member 76 .

[0047] The wiring members 51 to 59, wiring members 61 to 66, and wiring members 71 to 76 of the semiconductor module 1 can be bonding wires (thin metal wires). In the following description, the wiring members 51 to 59, wiring members 61 to 66, and wiring members 71 to 76 are also described as bonding wires 51 to 59, bonding wires 61 to 66, and bonding wires 71 to 76. For example, in the semiconductor module 1, Figure 3 As shown, the emitter 301 of each semiconductor element 3 is connected to the anode of the semiconductor element 4 by four bonding wires 56, and is connected to the conductor pattern 202B of the wiring board 2B by four bonding wires 57. In addition, in the semiconductor module 1 of the present embodiment, for each emitter 301 of the semiconductor elements 3D to 3F connected in parallel, the conductor pattern 202B and the conductor pattern 204B connected to the control terminal (auxiliary emitter terminal) 807 are connected by separate bonding wires 74D to 74F. Moreover, in the semiconductor module 1 of the present embodiment, the length of the wiring section shared with the main current path in the auxiliary emitter wiring is changed according to the length of the auxiliary emitter wiring from the different emitters 301 in each semiconductor element 3D to 3F to the control terminal (auxiliary emitter terminal) 807. Specifically, as Figure 3As shown in the example, the longer the auxiliary emitter wiring is, the shorter the wiring section shared with the main current path is. Figure 3 Only the auxiliary emitter wiring for semiconductor elements 3D to 3F connected in parallel between the third main terminal 803 and the second main terminal 802 is illustrated. The auxiliary emitter wiring for semiconductor elements 3A to 3C connected in parallel between the first main terminal 801 and the third main terminal 803 can have the same structure as the auxiliary emitter wiring for semiconductor elements 3D to 3F.

[0048] The length of the auxiliary emitter wiring is represented by the sum of the length of the bonding wire 57 connecting the emitter 301 of the semiconductor element 3 and the conductor pattern 202B of the wiring board 2B, the length of the bonding wire 74 connecting the conductor pattern 202B and the conductor pattern 204B, the distance from the connection point of the bonding wire 57 to the connection point of the bonding wire 74 on the conductor pattern 202B, and the distance from the connection point of the bonding wire 57 to the control terminal 807 on the conductor pattern 204B.

[0049] exist Figure 3 In the example, the lengths S0 of the bonding wires 57D to 57F connected to the emitters 301 of the semiconductor elements 3D to 3E are substantially the same, and the distances S1 from the connection points K0 on the conductor pattern 202B side of the bonding wires 57D to 57F to the connection points K4 on the conductor pattern 204B side of the bonding wires 74D to 74F when viewed from above are substantially the same. The "connection point" in this specification refers to a representative point in the area where the conductor pattern of the wiring board 2 and the third wiring are connected. In addition, Figure 3 In the example, 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 S23>S22>S21. In this case, Figure 3 As shown in the example, the distance G1 from connection point K0 of bonding wire 57D to connection point K1 of bonding wire 74D on conductor pattern 202B, the distance G2 from connection point K0 of bonding wire 57E to connection point K2 of bonding wire 74E, and the distance G3 from connection point K0 of bonding wire 57F to connection point K3 of bonding wire 74F on conductor pattern 204B of wiring board 2B have a magnitude relationship of G3 < G2 < G1. This makes it easier to even out the voltage drop in the section from connection point K5 of bonding wire 75 on conductor pattern 204B of wiring board 2B to emitter 301 in the auxiliary emitter wiring of semiconductor elements 3D to 3F connected in parallel, for example.

[0050] Figure 5Ais an equivalent circuit diagram illustrating an example of the inductance of the auxiliary emitter wiring in the semiconductor module according to one embodiment. Figure 5B This is a graph illustrating an example of a switching operation in a semiconductor module according to an embodiment.

[0051] For the above reference Figures 1 to 4 The auxiliary emitter wiring for the switching elements (semiconductor elements) 3D to 3F in the semiconductor module 1 described above can be expressed as follows, focusing on the inductance. Figure 5A The equivalent circuit diagram of . Figure 5A In the figure, the white circle (○) marked with “E” and Figure 3 The emitter electrodes 301 of the semiconductor elements 3D to 3F shown in FIG. 3 correspond to the connection points E of the bonding wires 57D to 57F. Figure 5A The connection points K1 to K3 and the connection point K5 in Figure 3 The connection points K1 to K3 and the connection point K5 correspond to each other.

[0052] Figure 5A In the circuit diagram, the magnitude relationship between inductance L1 in the section from connection point E to connection point K1 of switching element 3D, inductance L2 in the section from connection point E to connection point K2 of switching element 3E, and inductance L3 in the section from connection point E to connection point K3 of switching element 3F corresponds to the magnitude relationship between the lengths of the respective sections in the auxiliary emitter wiring, achieving the relationship L3 < L2 < L1. Similarly, the magnitude relationship between inductances L4 to L6 in the section from each of connection points K1 to K3 to connection point K5 corresponds to the magnitude relationship between the lengths of the respective sections in the auxiliary emitter wiring, achieving the relationship L6 > L5 > L4. Meanwhile, the magnitude relationship of the inductance of the entire auxiliary emitter wiring is (L3 + L6) > (L2 + L5) > (L1 + L4). However, because the main current and its temporal variation are greater than the current flowing in a single section (a section where no main current flows) in the auxiliary emitter wiring, the inductances L1, L2, and L3 have a greater impact on the voltage drop than the inductances L4, L5, and L6. Therefore, by adjusting the positions of the connection points of bonding wires 74D to 74F with conductor pattern 202B and conductor pattern 204B of wiring board 2B, the voltage drop in the auxiliary emitter wiring of each switching element 3D to 3F can be easily made uniform.

[0053] Furthermore, by making the voltage drop across the auxiliary emitter wiring for each switching element 3D to 3F uniform, variations in switching speed, switching loss, etc. among the switching elements 3D to 3F connected in parallel can be reduced. Figure 5BThe waveforms of the collector current Ic and collector-emitter voltage Vce of the semiconductor elements 3D and 3F at the time of turning on, which are related to switching speed and switching loss in a conventional structure, are schematically shown. In the semiconductor module 1 of this embodiment, the difference between the waveforms of the collector current Ic of the semiconductor element 3D and the collector current Ic of the semiconductor element 3F, and the difference between the waveforms of the collector-emitter voltage Vce of the semiconductor element 3D and the collector-emitter voltage Vce of the semiconductor element 3F, are less than 1 / 4 of the waveform. Figure 5B . Furthermore, the differences between the waveforms of the collector current Ic and collector-emitter voltage Vce of semiconductor element 3E and those of semiconductor elements 3D and 3F are also small. In other words, in the semiconductor module 1 of this embodiment, variations in heat generation between switching elements (semiconductor elements) 3D to 3F can be suppressed, thereby improving the reliability of the semiconductor module 1.

[0054] For example, in the semiconductor devices (semiconductor modules) of Patent Documents 3 and 4, Figure 3 The conductor pattern 204B shown in the example is a portion of the auxiliary emitter wiring corresponding to the conductor pattern 204B, and is a conductor pattern where the main current does not flow, and is directly connected to the emitter of the semiconductor element using a bonding wire. That is, in the semiconductor devices of Patent Documents 3 and 4, the auxiliary emitter wiring does not include a section where the main current flows. In such semiconductor devices, the inductance of the auxiliary emitter wiring for each semiconductor element connected in parallel, for example, Figure 5A The inductances L4 to L6 in the intervals where the main current does not flow, as shown in the figure, vary. Consequently, the voltage drop across the auxiliary emitter wiring varies. Specifically, the semiconductor devices of Patent Documents 3 and 4 cannot utilize the inductance in the intervals where the main current flows to equalize the voltage drop across the auxiliary emitter wiring for each semiconductor element connected in parallel, as is done in the semiconductor module 1 of this embodiment. Consequently, the semiconductor devices of Patent Documents 3 and 4 have difficulty reducing variations in switching speed, switching loss, and other factors among the semiconductor elements connected in parallel.

[0055] In addition, in the semiconductor device (semiconductor module) of Patent Document 1, Figure 3 The conductor pattern 202B and the conductor pattern 204B shown in the example are connected by a bonding wire. In such a semiconductor device, for example, Figure 5AThe inductances L1 to L3 shown in the figure vary in the intervals where the main current flows, resulting in variations in the voltage drop. Specifically, the semiconductor device of Patent Document 1 cannot, unlike the semiconductor module 1 of this embodiment, utilize a combination of the inductances in the intervals where the main current flows and the inductances in the intervals where the main current does not flow, to equalize the voltage drop across the auxiliary emitter wiring for each semiconductor element connected in parallel. Therefore, the semiconductor device of Patent Document 1 is difficult to reduce variations in switching speed, switching loss, and other factors among the semiconductor elements connected in parallel. Furthermore, the semiconductor device of Patent Document 2, which connects two semiconductor elements in parallel, similarly cannot achieve a structure that utilizes the inductance in the intervals where the main current flows to equalize the voltage drop.

[0056] Figure 6 This 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. Figure 7A It is an explanation Figure 6 An equivalent circuit diagram showing an example of the inductance of the auxiliary emitter wiring in a semiconductor module is shown in FIG. Figure 7B It is an explanation Figure 6 A diagram showing an example of switching action in a semiconductor module. Figure 8 This is a partially enlarged plan view illustrating a modified example of the semiconductor module according to one embodiment.

[0057] Figure 6 The three semiconductor elements (switching elements) 3D to 3F shown in FIG are connected in parallel between the third main terminal 803 and the second main terminal 802 in the same manner as the semiconductor module 1 of this embodiment (see FIG. Figure 7A ). The emitters 301 of the semiconductor elements 3D to 3F arranged on the conductor pattern 201B of the wiring board 2 are connected to the conductor pattern 202B of the wiring board 2. However, the emitters 301 of the semiconductor elements 3D and 3F are directly connected to the conductor pattern 202B using bonding wires 57D and 57F. In contrast, the emitter 301 of the semiconductor element 3E is connected to the conductor pattern 202B via the anode of the diode element (semiconductor element) 4 connected in reverse parallel. In addition, Figure 6 In the semiconductor module shown in FIG, the conductor pattern 202B and the conductor pattern 204B which is a part of the auxiliary emitter wiring and is connected to the control terminal (auxiliary emitter terminal) not shown are connected by a single bonding wire 74. Figure 6 The auxiliary emitter wiring of the semiconductor module exemplified in FIG. 1 is similar to the auxiliary emitter wiring of the semiconductor device of Patent Document 1, for example.

[0058] for Figure 6 The auxiliary emitter wiring in the semiconductor module exemplified in FIG can be expressed as follows if the inductance is taken into consideration. Figure 7A The equivalent circuit diagram of . Figure 7A In the figure, the white circle (○) marked with “E” and Figure 6 The emitter 301 of the semiconductor elements 3D, 3E, and 3F illustrated in FIG corresponds to the connection point E of the bonding wires 57D, 56, and 57F. Figure 7A The connection point KK6 in Figure 6 The connection point K6 of the bonding wire corresponds to.

[0059] exist Figure 6 In the semiconductor module illustrated in , the length from the connection point E to the connection point K01 in the auxiliary emitter wiring for the semiconductor element 3D is substantially the same as the length from the connection point E to the connection point K03 in the auxiliary emitter wiring for the semiconductor element 3F. However, the length from the connection point E to the connection point K02 in the auxiliary emitter wiring for the semiconductor element 3E is longer than the length between the connection points in the auxiliary emitter wiring for the semiconductor elements 3D and 3F. In addition, compared with the distance from the connection point K01 to the connection point K6 in the auxiliary emitter wiring for the semiconductor element 3D, the distance from the connection point K02 to the connection point K6 in the auxiliary emitter wiring for the semiconductor element 3E and the distance from the connection point K03 to the connection point K6 in the auxiliary emitter wiring for the semiconductor element 3F are longer. In such a semiconductor module, as Figure 7A As shown in the example of inductors L8 to L10, the variation in inductance in the section from connection point E to connection point K6 where the main current flows in the auxiliary emitter wiring for each semiconductor element 3D to 3F becomes larger. In other words, the variation in voltage drop in the auxiliary emitter wiring for each semiconductor element (switching element) 3D to 3F becomes larger. In this case, Figure 7B As shown in the example, there is a tendency for the variations in switching speed, switching loss, etc. among the three semiconductor elements 3D to 3F connected in parallel to become larger. Figure 7B Schematically shows waveforms of the collector current Ic and the collector-emitter voltage Vce of the semiconductor elements 3D to 3F when they are turned on, which are related to the switching speed and the switching loss.

[0060] In contrast, in the semiconductor module 1 of the present embodiment, for example, Figure 8As shown, for each emitter 301 of the three semiconductor elements 3D to 3F connected in parallel, the conductor pattern 202B and the conductor pattern 204 of the wiring board 2B are connected by separate bonding wires 74D to 74F. At this time, as described above, by setting the auxiliary emitter wiring to be longer, the wiring section in the auxiliary emitter wiring that is shared with the main current path is shorter, thereby reducing the deviation in the voltage drop between the auxiliary emitter wirings for each of the three semiconductor elements (switching elements) 3D to 3F connected in parallel, and reducing the deviation in the switching speed, switching loss, etc. between the semiconductor elements 3D to 3F. In addition, as Figure 8 As shown in the example, when the semiconductor element 3 as a switch element and the semiconductor element 4 as a diode element have different sizes in a plan view, the semiconductor elements 3 and the semiconductor elements 4 are arranged alternately, thereby achieving a better result than when the semiconductor elements 3 are arranged so that the distance from the semiconductor element 3 to the conductor pattern 202B is the same (see FIG. Figure 3 ), the semiconductor element 3 and the semiconductor element 4 can be arranged closely, which is advantageous for miniaturization of the semiconductor module 1, etc.

[0061] Furthermore, the number of semiconductor elements (switching elements) 3 connected in parallel in the semiconductor module 1 is not limited to the three described above, but may be two or more. Furthermore, the switching element is not limited to an IGBT element, but may be, for example, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a BJT (Bipolar Junction Transistor), or the like. When the switching element is a power MOSFET, an auxiliary source wiring connected to the source electrode of the MOSFET is provided as wiring corresponding to the auxiliary emitter wiring. Furthermore, the diode element connected in antiparallel to the switching element may be, for example, an SBD (Schottky Barrier Diode), a JBS (Junction Barrier Schottky) diode, an MPS (Merged PN Schottky) diode, a PN diode, or the like. In addition, the semiconductor module 1 may use an RC (Reverse Conducting)-IGBT element that integrates the functions of a switching element and a diode element instead of the semiconductor element 3 as a switching element and the semiconductor element 4 as a diode element. Furthermore, the semiconductor module 1 may also include a gate drive circuit 12 (see Figure 4 )wait.

[0062] The location of the connection point on the conductor pattern 202 side through which the main current flows in the wiring members 71 and 74 used as part of the auxiliary emitter wiring in the semiconductor module 1 is not limited to a specific location, as long as the influence of the potential of the emitter 301 of the semiconductor element 3 corresponding to the wiring member is sufficiently greater than the influence of the potential of the emitter 301 of other semiconductor elements (in other words, the influence of the potential of the emitter 301 of other semiconductor elements is sufficiently small). In addition, for example, the direction in which the wiring members (bonding wires) 71 and 74 extend when viewed from above may be different from the direction in which the wiring members 53 and 57 extend. Furthermore, the directions in which the bonding wires 74D, 74E, and 74F extend when viewed from above 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 the control terminals (auxiliary emitter terminals) 806 and 807 provided in the housing 8 without the aid of the conductor pattern of the wiring board 2.

[0063] Some of the wiring members of semiconductor module 1 may also use metal plates such as copper plates instead of bonding wires. For example, wiring member 51 connecting first main terminal 801 to conductor pattern 201A of wiring board 2A, wiring member 53 connecting the emitters of semiconductor elements 3A-3C to conductor pattern 202A of wiring board 2A, and wiring member 56 connecting the emitters of semiconductor elements 3D-3F to conductor pattern 202B of wiring board 2B may also be metal plates such as leads or leadframes. For example, heat dissipation pattern 208 may be omitted from wiring board 2 of semiconductor module 1.

[0064] The semiconductor module 1 of the above embodiment is not limited to a specific application. The semiconductor module 1 equipped with the cooler 11 is particularly suitable for use in a high temperature environment. For example, the semiconductor module 1 of the above embodiment can be applied to a power conversion device such as an inverter device for a vehicle-mounted motor. Figure 9 , a vehicle to which the semiconductor module 1 of the present invention is applied will be described.

[0065] Figure 9 1 is a schematic plan view showing an example of a vehicle to which the semiconductor module of the present invention is applied. Figure 9 The vehicle 1501 shown is, for example, a four-wheeled vehicle having four wheels 1502. Vehicle 1501 may also be, for example, an electric vehicle that drives its wheels using 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 two-wheeled vehicles or railway vehicles.

[0066] Vehicle 1501 includes a drive unit 1503 for applying power to wheels 1502 and a control device 1504 for controlling drive unit 1503. Drive unit 1503 may be composed of, for example, at least one of an engine, a motor, and a hybrid power of an engine and a motor.

[0067] The control device 1504 controls (for example, controls power) the drive unit 1503. The control device 1504 includes the semiconductor module 1 including the cooler 11 of the above-described embodiment. The semiconductor module 1 can be configured to control power to the drive unit 1503.

[0068] The semiconductor module 1 of the above embodiment can also be applied to industrial power conversion devices such as inverter devices that drive motors in elevators, escalators, and building air conditioning systems. Figure 4 The circuit formed in the semiconductor module 1 may have only Figure 4 The upper arm (circuit portion between main terminal 801 and main terminal 803) or the lower arm (circuit portion between main terminal 803 and main terminal 802) of the half-bridge circuit may include multiple (e.g., three) half-bridge inverter circuits. The circuit formed in semiconductor module 1 may also be a full-bridge inverter circuit. Furthermore, the circuit formed in semiconductor module 1 is not limited to a power conversion circuit that converts DC to AC and may also be other circuits.

[0069] The characteristic points of the above-mentioned embodiment are summarized below.

[0070] The semiconductor module of the above-mentioned embodiment includes: a wiring board, which has a first conductor pattern and a second conductor pattern arranged on one surface of an insulating substrate; a plurality of semiconductor elements, which are arranged on the first conductor pattern of the wiring board; a first wiring member, which connects the first main electrodes of the plurality of semiconductor elements to the first conductor pattern respectively; a second wiring member, which connects the second main electrodes of the plurality of semiconductor elements to the second conductor pattern respectively; a first terminal, which is connected to the first main electrode of the plurality of semiconductor elements by means of the first conductor pattern and through which a main current flows; a second terminal, which is connected to the second main electrode of the plurality of semiconductor elements by means of the second conductor pattern and through which a main current flows; and a third terminal, which is connected to the second conductor pattern by means of a third wiring member. Each of the multiple 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 multiple wiring members corresponding to the multiple semiconductor elements, respectively. The distance from the connection point of the multiple wiring members to the connection point of the second wiring member on the second conductor pattern is different according to the distance from a specified position in the third terminal to the connection point between the second main electrode of the multiple semiconductor elements and the second wiring member.

[0071] In the semiconductor module of the above-mentioned embodiment, the plurality of semiconductor elements include a first semiconductor element and a second semiconductor element, and when the distance from the prescribed position in the third terminal portion to the connection point between the second main electrode of the first semiconductor element and the second wiring member is longer than the distance from the prescribed position in the third terminal portion to the connection point between the second main electrode of the second semiconductor element and the second wiring member, the distance on the second conductive pattern from the connection point of the wiring member corresponding to the first semiconductor element in the third wiring member 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 on the second conductive pattern from the connection point of the wiring member corresponding to the second semiconductor element in the third wiring member to the connection point of the second wiring member connected to the second main electrode of the second semiconductor element.

[0072] In the semiconductor module of the above embodiment, the third terminal is connected to a control circuit that generates a control signal to be applied to the control electrodes of the plurality of semiconductor elements.

[0073] In the semiconductor module of the above embodiment, each of the plurality of semiconductor elements includes the switching element and a diode element connected in antiparallel to the switching element.

[0074] In the semiconductor module of the above embodiment, the semiconductor module further includes a plurality of second semiconductor elements connected to each of the plurality of semiconductor elements, each of the plurality of second semiconductor elements including a diode element connected in antiparallel to the switching element of each of the plurality of semiconductor elements.

[0075] In the semiconductor module of the above embodiment, the second wiring member includes a wiring member that connects the second main electrode of the semiconductor element and the second conductor pattern via an electrode of one of the plurality of second semiconductor elements.

[0076] In the semiconductor module of the above embodiment, the plurality of semiconductor elements are arranged on the first conductor pattern such that the lengths of the second wiring members from the connection point with the second main electrode to the connection point with the second conductor pattern are substantially the same.

[0077] In the semiconductor module of the above embodiment, the first wiring member is a bonding material, and the second wiring member and the third wiring member are bonding wires.

[0078] In the semiconductor module of the above embodiment, the switching element is an IGBT (Insulated Gate Bipolar Transistor) element, the first main electrode is a collector of the IGBT element, and the second main electrode is an emitter of the IGBT element.

[0079] In the semiconductor module of the above embodiment, the plurality of semiconductor elements are arranged at the same distance from the second conductor pattern.

[0080] The semiconductor module of the above embodiment further includes a cooler that is arranged in a direction opposite to a direction in which the semiconductor element is arranged on the wiring board and is connected to the wiring board.

[0081] The vehicle according to the above-described embodiment includes the semiconductor module according to the above-described embodiment.

[0082] Furthermore, the present invention is not limited to the above-described embodiments and may be subjected to various modifications, substitutions, and variations without departing from the scope of the technical concept. Furthermore, if technological advancement or the development of other technologies allow the technical concept to be realized in other ways, such methods may also be used for implementation. Therefore, the claims encompass all possible embodiments that fall within the scope of the technical concept.

[0083] Industrial applicability

[0084] As described above, the present invention has the effect of reducing the deviation of switching actions between multiple switching elements connected in parallel in a semiconductor module, and can suppress the decrease in the operating reliability of the semiconductor module caused by the deviation of heat generation of the switching elements. It is particularly useful for industrial or automotive semiconductor modules used as power conversion devices.

Claims

1. A semiconductor module, wherein: The semiconductor module 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 the first main electrodes of the plurality of semiconductor elements to the first conductor pattern; a second wiring member connecting 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 a current flowing between the first main electrode and the second main electrode. The third wiring member includes a plurality of wiring members corresponding to the plurality of semiconductor elements, respectively. The distances from the connection points of the plurality of wiring members to the connection points of the second wiring member on the second conductor pattern vary depending on the distances from a predetermined position in the third terminal to the connection points of the second main electrodes of the plurality of semiconductor elements with the second wiring member.

2. The semiconductor module according to claim 1, wherein The plurality of semiconductor elements include a first semiconductor element and a second semiconductor element, In a case where the distance from the prescribed position in the third terminal portion to the connection point between the second main electrode of the first semiconductor element and the second wiring member is longer than the distance from the prescribed position in the third terminal portion to the connection point between the second main electrode of the second semiconductor element and the second wiring member, the distance on the second conductive pattern from the connection point of the wiring member corresponding to the first semiconductor element in the third wiring member 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 on the second conductive pattern from the connection point of the wiring member corresponding to the second semiconductor element in the third wiring member to the connection point of the second wiring member connected to the second main electrode of the second semiconductor element.

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

4. The semiconductor module according to claim 3, wherein 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 , wherein: The semiconductor module further includes a plurality of second semiconductor elements connected to each of the plurality of semiconductor elements. Each of the plurality of second semiconductor elements includes a diode element connected in antiparallel to the switching element of each of the plurality of semiconductor elements. The semiconductor module according to claim 5 , wherein: The second wiring member includes a wiring member that connects the second main electrode of the semiconductor element and the second conductor pattern via an electrode of one of the plurality of second semiconductor elements.

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

8. 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. The semiconductor module according to claim 1, wherein The switching element is an IGBT element, ie, an insulated gate bipolar transistor element. The first main electrode is a collector of the IGBT element, and the second main electrode is an emitter of the IGBT element.

10. The semiconductor module according to claim 1, wherein The plurality of semiconductor elements are arranged at the same distance from the second conductor pattern.

11. The semiconductor module according to any one of claims 1 to 10, wherein The semiconductor module further includes a cooler that is arranged in a direction opposite to a direction in which the semiconductor element is arranged on the wiring board and is connected to the wiring board.

12. A vehicle, wherein: This vehicle includes the semiconductor module according to claim 10 .

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