Wiring boards, power converters

Abstract

To provide a technique capable of improving the reliability when driving a plurality of semiconductor elements connected in parallel with one driving circuit.SOLUTION: A wiring board 400 according to one embodiment of the present disclosure includes pairs of hard substrates 410a to 410c provided for a plurality of semiconductor switching elements SW connected in parallel, a soft substrate 420 at least a part of which is provided to be held between the pair of hard substrates 410a, the pair of hard substrates 410b, and the pair of hard substrates 410c, electrodes 460a to 460c connected to gate terminals of the semiconductor switching elements SW, electrodes 470a to 470c connected to source terminals of the semiconductor switching elements SW, a wire 480 at least partly provided to the soft substrate 420 and connecting the electrodes 460a to 460c in parallel, and a wire 490 at least partly provided to the soft substrate 420 and connecting the electrodes 470a to 470c in parallel.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a wiring board and the like.

Background Art

[0002] For example, a wiring board for driving a plurality of parallel-connected semiconductor elements with one drive circuit is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in order to suppress the deviation in switching of a plurality of parallel-connected semiconductor elements, it is desirable that the wiring lengths between the drive circuit and each semiconductor element be configured to be substantially the same.

[0005] However, in Patent Document 1, a substrate for wiring the gate terminal (base terminal) and the source terminal (emitter terminal) is provided for each of the plurality of semiconductor elements, and the substrates are connected to each other by a connector and wiring, so that the wiring lengths between the drive circuit and the gate terminal and the source terminal of each semiconductor element are made substantially the same. Therefore, for example, in order to adjust the wiring length, it is necessary to adopt a route passing through another substrate different from the substrate on which the target gate terminal exists, and the wiring length between the drive circuit and the gate terminal of the semiconductor element may become long. As a result, due to an increase in parasitic inductance accompanying an increase in the wiring length, the performance of the semiconductor element may not be able to be extracted, or a gate oscillation phenomenon may be caused due to an increase in parasitic impedance. Also, for example, a contact failure may occur at the connector fitting portion due to assembly defects or the addition of mechanical vibration. Therefore, there is room for improvement in terms of reliability.

[0006] Therefore, in light of the above issues, the objective is to provide a technology that can further improve the reliability when driving multiple semiconductor elements connected in parallel with a single drive circuit. [Means for solving the problem]

[0007] To achieve the above objective, in one embodiment of this disclosure, A predetermined electrode provided for connection to the outside of the wiring board, For the predetermined electrode A pair of rigid substrates provided for each of the multiple semiconductor elements connected in parallel, At least a portion thereof is a soft substrate provided so as to be sandwiched between all of the pair of hard substrates, A first electrode connecting the control terminal of the semiconductor element to the hard substrate or the soft substrate, A second electrode connecting the reference potential terminal of the semiconductor element to the rigid substrate or the flexible substrate, At least a portion of the soft substrate is provided The entire structure is provided on the wiring board. The first electrode for each of the plurality of semiconductor elements , with respect to the third electrode included in the predetermined electrode The first wire is connected in parallel, At least a portion of the soft substrate is provided The entire structure is provided on the wiring board. The second electrode for each of the plurality of semiconductor elements , with respect to the fourth electrode included in the predetermined electrode It comprises a second wiring connected in parallel, A wiring board is provided.

[0008] In other embodiments of this disclosure, A predetermined electrode provided for connection to the outside of the wiring board, For the predetermined electrode A rigid substrate is provided for each of the multiple semiconductor elements connected in parallel, A flexible substrate connecting the rigid substrates, A first electrode connecting the control terminal of the semiconductor element and the hard substrate, A second electrode connecting the reference potential terminal of the semiconductor element and the rigid substrate, Provided on the rigid substrate and the flexible substrate, the first electrodes for each of the plurality of semiconductor elements , with respect to the third electrode included in the predetermined electrode A first wiring for connecting in parallel; Provided on the rigid substrate and the flexible substrate, the second electrodes for each of the plurality of semiconductor elements , with respect to the fourth electrode included in the predetermined electrode A second wiring for connecting in parallel, and includes: All of the rigid substrates for each of the plurality of semiconductor elements are connected by the flexible substrate, A wiring substrate is provided.

[0009] Moreover, in still another embodiment of the present disclosure, The above-mentioned wiring substrate; The plurality of semiconductor elements, and includes: A power conversion device is provided.

Advantages of the Invention

[0010] According to the above embodiment, the reliability when driving a plurality of semiconductor elements connected in parallel with one drive circuit can be further improved.

Brief Description of the Drawings

[0012] The embodiments will be described below with reference to the drawings.

[0013] [First example of a wiring board] A first example of the wiring board 400 according to this embodiment will be described with reference to Figures 1 to 3.

[0014] Figure 1 is a circuit diagram showing an example of a power converter 1 including a first example of a wiring board 400. Figure 2 is a perspective view showing a first example of a wiring board 400. Figure 3 is a top view showing a first example of a wiring board 400.

[0015] In the following explanation, we may use the Cartesian coordinate system defined by the X, Y, and Z axes in the diagram. Furthermore, the positive and negative directions of the X axis may be collectively referred to as the X-axis direction, the positive and negative directions of the Y axis may be collectively referred to as the Y-axis direction, and the positive and negative directions of the Z axis may be collectively referred to as the Z-axis direction.

[0016] The power converter 1 converts the power from a DC power supply PS to a predetermined power (for example, three-phase AC power of a predetermined voltage and frequency) and supplies it to a predetermined load. The power converter 1 is installed in, for example, industrial machinery for factories, railway vehicles, automobiles, etc.

[0017] The power converter 1 has an arm section 10 including a semiconductor switch element SW, and a leg section 20, which is formed by connecting two arm sections 10 in series, is provided between the positive and negative lines of a DC power supply PS. For example, the power converter 1 is an inverter device that can output three-phase AC power by connecting three leg sections 20 in parallel between the positive and negative lines of a DC power supply PS.

[0018] The arm section 10 includes semiconductor modules 100a to 100c, wiring 200a and 200b, a drive circuit board 300, a wiring board 400, and an electrical circuit 500.

[0019] Each of the semiconductor modules 100a to 100c includes a semiconductor switch element SW.

[0020] A semiconductor switch element SW (an example of a semiconductor element) is voltage-driven and, for example, as shown in Figure 1, is a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Alternatively, the semiconductor switch element SW may be an IGBT (Insulated Gate Bipolar Transistor) or a HEMT (High Electron Mobility Transistor). Furthermore, the semiconductor switch element SW may be constructed primarily from silicon (Si). Alternatively, the semiconductor switch element SW may be constructed primarily from a wide-bandgap semiconductor material. Examples of wide-bandgap semiconductor materials include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and carbon (diamond (C)).

[0021] For example, as shown in Figures 2 and 3, the semiconductor modules 100a to 100c each have a roughly rectangular parallelepiped shape with sides along the X, Y, and Z axes, and are arranged at roughly equal intervals in the X-axis direction. The term "roughly" is used to allow for tolerances such as manufacturing errors, and will be used in the same sense hereafter.

[0022] Wires 200a and 200b are used to connect multiple (in this example, three) semiconductor modules 100a to 100c (i.e., multiple semiconductor switch elements SW) in parallel. Specifically, wire 200a is provided to connect the drain terminals of the multiple semiconductor switch elements SW, i.e., the drain electrodes of the multiple semiconductor modules 100a to 100c to each other. Wires 200b connect the source terminals (an example of a reference potential terminal) of the multiple semiconductor switch elements SW, i.e., the source electrodes of the multiple semiconductor modules 100a to each other.

[0023] Furthermore, if the semiconductor switch element SW is a bipolar transistor such as an IGBT, the source terminal, drain terminal, and gate terminal (an example of a control terminal) are replaced by the emitter terminal (an example of a reference potential terminal), collector terminal, and base terminal (an example of a control terminal), respectively.

[0024] The drive circuit board 300 is a board on which drive circuits for multiple semiconductor switch elements SW are mounted.

[0025] The wiring board 400 has wiring mounted on it for driving multiple semiconductor modules 100a to 100c (i.e., multiple semiconductor switch elements SW) by a drive circuit. The wiring board 400 includes rigid substrates 410a to 410c, a flexible substrate 420, electrodes 450, electrodes 460a to 460c, electrodes 470a to 470c, and wiring 480 and 490.

[0026] Furthermore, the connection and fixing of the wiring board 400 (for example, the rigid substrates 410a to 410c) and the semiconductor modules 100a to 100c may be achieved by any method. For example, the connection and fixing between the wiring board 400 and the semiconductor modules 100a to 100c can be achieved by fastening with screws or by crimping under pressure.

[0027] The rigid substrates 410a to 410c are provided to correspond to each of the semiconductor modules 100a to 100c. The rigid substrates 410a to 410c may be formed from any material. For example, the rigid substrates 410a to 410c may be glass epoxy substrates or the like.

[0028] For example, as shown in Figures 2 and 3, the rigid substrate 410a is provided on the upper surface (i.e., the end face in the positive Z-axis direction) of the semiconductor module 100a. The rigid substrate 410a has a flat plate shape substantially parallel to the X and Y axes, and has a substantially rectangular shape with sides in the X and Y axis directions when viewed from above. Two rigid substrates 410a are provided. The two rigid substrates 410a function as a pair of rigid substrates 410a, as will be described later.

[0029] For example, as shown in Figures 2 and 3, the rigid substrate 410b is provided on the upper surface (i.e., the end face in the positive Z-axis direction) of the semiconductor module 100b. Similar to the rigid substrate 410a, the rigid substrate 410b has a flat plate shape substantially parallel to the X and Y axes, and has a substantially rectangular shape with sides in the X and Y axis directions when viewed from above. Similar to the rigid substrate 410a, two rigid substrates 410b are provided. The two rigid substrates 410b function as a pair of rigid substrates 410b, as will be described later.

[0030] For example, as shown in Figures 2 and 3, the rigid substrate 410c is provided at approximately the center of the X-axis and Y-axis directions on the upper surface (i.e., the end face in the positive Z-axis direction) of the semiconductor module 100c. The rigid substrate 410c, like the rigid substrates 410a and 410b, has a flat plate shape that is approximately parallel to the X-axis and Y-axis, and has a roughly rectangular shape with sides in the X-axis and Y-axis directions when viewed from above. Similar to the rigid substrate 410a, two rigid substrates 410b are provided. The two rigid substrates 410b function as a pair of rigid substrates 410c, as will be described later.

[0031] The flexible substrate 420 is provided so as to be sandwiched between the pair of rigid substrates 410a, the pair of rigid substrates 410b, and the pair of rigid substrates 410c. The flexible substrate 420 can be manufactured from any material. For example, the flexible substrate 420 may be a polyimide substrate.

[0032] The flexible substrate 420 has a roughly rectangular shape, as shown in Figures 2 and 3, for example, with dimensions approximately parallel to the X and Y axes and with a dimension in the X-axis direction being longer than the dimension in the Y-axis direction. Specifically, the flexible substrate 420 has a dimension in the Y-axis direction that is approximately the same as or smaller than that of the rigid substrates 410a to 410c, and a dimension in the X-axis direction that is approximately the same as the distance between the end face of the rigid substrate 410a in the negative X-axis direction and the end face of the rigid substrate 410c in the positive X-axis direction. The flexible substrate 420 is sandwiched between the pair of rigid substrates 410a from above and below (i.e., in the positive and negative Z-axis directions) at its end in the negative X-axis direction, sandwiched between the pair of rigid substrates 410b from above and below at its central part in the X-axis direction, and sandwiched between the pair of rigid substrates 410c from above and below at its end in the positive X-axis direction. As a result, on top of the semiconductor module 100a (positive Z-axis side), the hard substrate 410a, the soft substrate 420, and the hard substrate 410a are stacked in order from bottom (negative Z-axis side). Similarly, on top of the semiconductor module 100b, the hard substrate 410b, the soft substrate 420, and the hard substrate 410b are stacked in order from bottom. Similarly, on top of the semiconductor module 100c, the hard substrate 410c, the soft substrate 420, and the hard substrate 410c are stacked in order from bottom. In the X-axis direction, the soft substrate 420 is exposed in the range between adjacent pairs of hard substrates 410a and pairs of hard substrates 410b, and in the range between adjacent pairs of hard substrates 410b and pairs of hard substrates 410c.

[0033] The flexible substrate 420 and at least one of the pair of rigid substrates 410a are electrically connected. For the connection between the flexible substrate 420 and the rigid substrate 410a, for example, a general via hole is used. The via hole may be a through via, a stacked via, a buried via, etc. The same may apply to the via holes used for via connections described later. In addition, known methods such as copper inlays or copper backfilled vias may be optionally used for the connection between the flexible substrate 420 and the rigid substrate 410a.

[0034] The electrode 450 is used to connect to the drive circuit board 300 via the electrical circuit 500. For example, as shown in Figures 2 and 3, the electrode 450 is located at the center of the hard substrate 410b in the X-axis direction and at the end in the negative Y-axis direction. The electrode 450 includes electrode 450a (third electrode) and electrode 450b.

[0035] Electrode 460a (an example of the first electrode) is connected to the gate electrode of the semiconductor module 100a, that is, to the gate terminal of the semiconductor switch element SW included in the semiconductor module 100a. For example, as shown in Figure 2, electrode 460a is provided on the upper hard substrate 410a of the pair of hard substrates 410a, where the surface in the positive Z-axis direction is exposed. Alternatively, electrode 460a may be provided on the lower (negative Z-axis direction) hard substrate 410a of the pair of hard substrates 410a, or on the portion of the soft substrate 420 between the pair of hard substrates 410a.

[0036] For example, as shown in Figures 2 and 3, the electrode 460a is provided on the upper hard substrate 410a at a location closer to the negative X-axis direction and closer to the positive Y-axis direction.

[0037] Electrode 460b (an example of the first electrode) is connected to the gate electrode of the semiconductor module 100b, that is, to the gate terminal of the semiconductor switch element SW included in the semiconductor module 100b. For example, as shown in Figures 2 and 3, electrode 460b is provided on the upper hard substrate 410b of a pair of hard substrates 410b, where the surface in the positive Z-axis direction is exposed. Alternatively, electrode 460b may be provided on the lower (negative Z-axis direction) hard substrate 410b of the pair of hard substrates 410b, or on the portion of the soft substrate 420 between the pair of hard substrates 410b.

[0038] For example, as shown in Figures 2 and 3, the electrode 460b is provided on the upper hard substrate 410b at a location closer to the negative X-axis direction and closer to the positive Y-axis direction.

[0039] The electrode 460c (an example of the first electrode) is connected to the gate electrode of the semiconductor module 100c, that is, to the gate terminal of the semiconductor switch element SW included in the semiconductor module 100c. For example, as shown in Figures 2 and 3, the electrode 460c is provided on the upper hard substrate 410c of the pair of hard substrates 410c, where the surface in the positive Z-axis direction is exposed. Alternatively, the electrode 460c may be provided on the lower (negative Z-axis direction) hard substrate 410c of the pair of hard substrates 410c, or on the portion of the soft substrate 420 between the pair of hard substrates 410c.

[0040] For example, as shown in Figures 2 and 3, the electrode 460c is provided on the upper hard substrate 410c at a location closer to the negative X-axis direction and closer to the positive Y-axis direction.

[0041] Electrode 470a (an example of a second electrode) is connected to the source electrode of the semiconductor module 100a, that is, to the source terminal of the semiconductor switch element SW included in the semiconductor module 100a. For example, as shown in Figures 2 and 3, electrode 470a is provided on the upper hard substrate 410a of the pair of hard substrates 410a, where the surface in the positive Z-axis direction is exposed. Alternatively, electrode 470a may be provided on the lower (negative Z-axis direction) hard substrate 410a of the pair of hard substrates 410a, or on the portion of the soft substrate 420 between the pair of hard substrates 410a.

[0042] For example, as shown in Figures 2 and 3, the electrode 470a is provided on the upper hard substrate 410a at a location closer to the negative X-axis and negative Y-axis directions.

[0043] Electrode 470b (an example of a second electrode) is connected to the source electrode of the semiconductor module 100b, that is, to the source terminal of the semiconductor switch element SW included in the semiconductor module 100b. For example, as shown in Figures 2 and 3, electrode 470b is provided on the upper hard substrate 410b of a pair of hard substrates 410b, where the surface in the positive Z-axis direction is exposed. Alternatively, electrode 470b may be provided on the lower (negative Z-axis direction) hard substrate 410b of the pair of hard substrates 410b, or on the portion of the soft substrate 420 between the pair of hard substrates 410b.

[0044] For example, as shown in Figures 2 and 3, the electrode 470b is provided on the upper hard substrate 410b at a location closer to the negative X-axis and negative Y-axis directions.

[0045] Electrode 470c (an example of a second electrode) is connected to the source electrode of the semiconductor module 100c, that is, to the source terminal of the semiconductor switch element SW included in the semiconductor module 100c. For example, as shown in Figures 2 and 3, electrode 470c is provided on the upper hard substrate 410c of a pair of hard substrates 410c, where the surface in the positive Z-axis direction is exposed. Alternatively, electrode 470c may be provided on the lower (negative Z-axis direction) hard substrate 410c of a pair of hard substrates 410c, or on the portion of the soft substrate 420 between the pair of hard substrates 410c.

[0046] For example, as shown in Figures 2 and 3, the electrode 470c is provided on the upper hard substrate 410c at a location closer to the negative X-axis and negative Y-axis directions.

[0047] Furthermore, in addition to electrodes 460a to 460c and electrodes 470a to 470c, the wiring board 400 may also be provided with electrodes (auxiliary terminals) for monitoring the status of each semiconductor switch element SW of the semiconductor modules 100a to 100c. The auxiliary terminals are, for example, high-voltage auxiliary terminals for withstand voltage testing.

[0048] Wiring 480 (an example of the first wiring) connects electrodes 460a to 460c in parallel. Specifically, wiring 480 connects electrode 450a to each of electrodes 460a to 460c. Wiring 480 includes wirings 480a to 480c.

[0049] Wiring 480a is the wiring portion of wiring 480 that connects electrodes 450a and 460a. Wiring 480b is the wiring portion of wiring 480 that connects electrodes 450a and 460b. Wiring 480c is the wiring portion of wiring 480 that connects electrodes 450a and 460c. Wirings 480a to 480c may be provided independently of each other, or a portion of them may be common starting from electrode 450a.

[0050] The wiring 480 is mainly provided on the flexible substrate 420. For example, the wiring 480 is mainly arranged on the flexible substrate 420 and is also provided on at least one of the rigid substrates 410a to 410c for the purpose of connecting to components, electrodes, etc. on the rigid substrates 410a to 410c. Alternatively, the wiring 480 may be provided only on the flexible substrate 420 among the rigid substrates 410a to 410c and the flexible substrate 420.

[0051] Wiring 490 (an example of the second wiring) connects electrodes 470a to 470c in parallel. Specifically, wiring 490 connects electrode 450b to each of electrodes 470a to 470c. Wiring 490 includes wirings 490a to 490c.

[0052] Wiring 490a is the wiring portion of wiring 490 that connects electrode 450b and electrode 470a. Wiring 490b is the wiring portion of wiring 490 that connects electrode 450b and electrode 470b. Wiring 490c is the wiring portion of wiring 490 that connects electrode 450b and electrode 470c. Wirings 490a to 490c may be provided independently of each other, or a portion of them may be common starting from electrode 450b.

[0053] The wiring 490 is provided, for example, on the flexible substrate 420 and at least one of the rigid substrates 410a to 410c. Alternatively, the wiring 490 may be provided only on the flexible substrate 420 among the rigid substrates 410a to 410c and the flexible substrate 420.

[0054] The circuit 500 connects the drive circuit board 300 and the electrodes 450 of the wiring board 400. The circuit 500 includes circuits 500a and 500b.

[0055] Circuit 500a connects the drive circuit board 300 to electrode 450a of the wiring board 400. Circuit 500b connects the drive circuit board 300 to electrode 450b of the wiring board 400.

[0056] Thus, the wiring board 400 is configured as a rigid-flexible substrate by a combination of rigid substrates 410a to 410c and a flexible substrate 420. Specifically, the wiring board 400 has a structure in which a pair of rigid substrates 410a, a pair of rigid substrates 410b, and a pair of rigid substrates 410c each form an outer layer, and the flexible substrate 420 forms an inner layer. The flexible substrate 420 is sandwiched between each of the pairs of rigid substrates 410a, a pair of rigid substrates 410b, and a pair of rigid substrates 410c, thereby enabling the connection of multiple semiconductor modules 100a to 100c's rigid substrates 430a to 430c to each other.

[0057] For example, when connecting rigid substrates 410a to 410b electrically using a connector, the absolute value of the wiring length may increase in order to match the wiring length between electrode 450a and electrodes 460a to 460c. This is because the length of the connection path needs to be adjusted by making the connection path by the connector go back and forth. As a result, the parasitic inductance may increase due to the increase in wiring length, which may prevent the semiconductor switch element SW from performing to its full potential. In addition, the increase in parasitic impedance due to the increase in wiring length may cause gate oscillation. Furthermore, connection failures may occur at the connector mating part due to assembly defects or the addition of mechanical vibrations. In particular, when mounted on moving objects such as railway vehicles and automobiles, mechanical vibrations are easily added, which may increase the concern about connection failures. Also, the connector may cause an increase in the height dimension (Z-axis direction), which may hinder the reduction of height dimension (low profile). In particular, in the case of automobiles, the mounting space for components is very limited and there is a high need for low profile, so this may have a significant impact on the ability to mount in automobiles.

[0058] In contrast, in this example, the wiring length between electrode 450a and electrodes 460a to 460c, which correspond to the gate electrodes of each semiconductor module 100a to 100c, can be adjusted by the wiring patterns on the rigid substrates 410a to 410c and the flexible substrate 420. Therefore, the degree of freedom of the wiring pattern makes it possible to suppress the increase in wiring length when aligning the wiring lengths between electrode 450a and electrodes 460a to 460c. As a result, the performance of the semiconductor switch element SW can be brought out to the desired level, and the occurrence of gate oscillation can be suppressed. Furthermore, since connectors are not used for interconnecting the rigid substrates 410a to 410c, the occurrence of connection failures can be suppressed, and the height of the wiring board 400 can be reduced. Thus, a wiring board 400 with higher reliability and operational stability can be realized. In addition, since the manufacturing process for connector mating is not required, labor in assembly work can be reduced, manufacturing efficiency can be improved, and manufacturing costs can be reduced.

[0059] [Second example of a wiring board] Next, a second example of the wiring board 400 according to this embodiment will be described with reference to Figures 4 to 6.

[0060] The following explanation will focus on the differences from the first example described above, and explanations of content that is the same as or corresponds to the first example may be omitted.

[0061] Figure 4 is a circuit diagram showing an example of a power converter 1 including a second example of the wiring board 400. Figure 5 is a perspective view showing a second example of the wiring board 400. Figure 6 is a top view showing a second example of the wiring board 400.

[0062] The wiring board 400 includes rigid substrates 430a to 430c, flexible substrates 440a and 440b, electrodes 450, electrodes 460a to 460c, electrodes 470a to 470c, and wiring 480 and 490.

[0063] The rigid substrates 430a to 430c are provided to correspond to each of the semiconductor modules 100a to 100c.

[0064] For example, as shown in Figures 5 and 6, the rigid substrate 430a is provided on the upper surface (i.e., the end face in the positive Z-axis direction) of the semiconductor module 100a. The rigid substrate 430a has a flat plate shape that is substantially parallel to the X and Y axes, and has a substantially rectangular shape with sides in the X-axis direction and Y-axis direction when viewed from above.

[0065] For example, as shown in Figures 5 and 6, the rigid substrate 430b is provided on the upper surface (i.e., the end face in the positive Z-axis direction) of the semiconductor module 100b. Similar to the rigid substrate 430a, the rigid substrate 430b has a flat plate shape that is substantially parallel to the X and Y axes, and has a substantially rectangular shape with sides in the X-axis direction and Y-axis direction when viewed from above.

[0066] For example, as shown in Figures 5 and 6, the rigid substrate 430c is provided at approximately the center of the X-axis and Y-axis directions on the upper surface (i.e., the end face in the positive Z-axis direction) of the semiconductor module 100c. The rigid substrate 430c, like the rigid substrates 430a and 430b, has a flat plate shape that is approximately parallel to the X-axis and Y-axis, and has a roughly rectangular shape with sides in the X-axis and Y-axis directions when viewed from above.

[0067] The flexible substrate 440a is electrically connected to the rigid substrates 430a and 430b at both ends, so as to connect them. For example, as shown in Figures 5 and 6, the flexible substrate 440a has a flat plate shape that is substantially parallel to the X and Y axes, and has a substantially rectangular shape when viewed from above, with each side extending in the X and Y directions. The end in the negative X direction is electrically connected to the upper surface (the end face in the positive Z direction) of the rigid substrate 430a, and the end in the positive X direction is electrically connected to the upper surface of the rigid substrate 430b.

[0068] The flexible substrate 440b is electrically connected to the rigid substrates 430b and 430c at both ends, so as to connect them. For example, as shown in Figures 5 and 6, the flexible substrate 440b has a flat plate shape that is substantially parallel to the X and Y axes, and has a substantially rectangular shape when viewed from above, with each side extending in the X and Y directions. The end in the negative X direction is electrically connected to the upper surface (the end face in the positive Z direction) of the rigid substrate 430b, and the end in the positive X direction is electrically connected to the upper surface of the rigid substrate 430b.

[0069] The electrical connection between the flexible substrate 440a and the rigid substrates 430a and 430b may be achieved by any joining method. For example, the electrical connection between the flexible substrate 440a and the rigid substrates 430a and 430b may be achieved by soldering. The same may apply to the electrical connection between the flexible substrate 440b and the rigid substrates 430b and 430c. Furthermore, the mechanical connection (holding) between the flexible substrate 440a and the rigid substrates 430a and 430b may be achieved by any method. For example, the mechanical connection (holding) between the flexible substrate 440a and the rigid substrates 430a and 430b may be achieved by soldering or resin. The same may apply to the mechanical connection (holding) between the flexible substrate 440b and the rigid substrates 430b and 430c.

[0070] Wiring 480 is placed on rigid substrates 430a to 430c and flexible substrates 440a and 440b. The same applies to wiring 490.

[0071] Thus, in this example, the wiring board 400 has a configuration equivalent to a rigid-flexible substrate, consisting of a combination of rigid substrates 430a to 430c and flexible substrates 440a and 440b. Specifically, the wiring board 400 has a structure in which rigid substrates 430a to 430c, each corresponding to a plurality of semiconductor modules 100a to 100c, are electrically connected to one another by flexible substrates 440a and 440b.

[0072] As a result, in this example, the wiring length between electrode 450a and electrodes 460a to 460c can be adjusted by the wiring patterns on the rigid substrates 430a to 430c and the flexible substrates 440a and 440b. Therefore, as in the first example described above, the degree of freedom of the wiring pattern makes it possible to suppress the increase in wiring length when aligning the wiring lengths between electrode 450a and electrodes 460a to 460c. As a result, the performance of the semiconductor switch element SW can be brought out to the desired level, and the occurrence of gate oscillation can be suppressed. In addition, since connectors are not used for interconnecting the rigid substrates 410a to 410c, the occurrence of connection failures can be suppressed, and the height of the wiring board 400 can be reduced. Thus, a wiring board 400 with higher reliability and operational stability can be realized. Furthermore, since the manufacturing process for connector mating is not required, labor in assembly work can be reduced, manufacturing efficiency can be improved, and manufacturing costs can be reduced. Furthermore, since the rigid substrates 430a-430c and the flexible substrates 440a, 440b are only joined using known methods, the adoption of a simpler process can further promote labor savings in assembly work, improved manufacturing efficiency, and reduced manufacturing costs. [Third example of a wiring board] Next, with reference to Figure 7, a third example of the wiring board 400 according to this embodiment will be described.

[0073] The following explanation will focus on the differences from the first and second examples described above, and explanations of the same or corresponding content as in the first and second examples may be omitted. In addition, in this example, the circuit diagram of the power converter 1 including the wiring board 400, the perspective view of the wiring board 400, and the top view of the wiring board 400 are the same as in the second example described above, so their illustration will be omitted, and the explanation will be based on Figures 4 to 6 of the second example described above.

[0074] Figure 7 is a cross-sectional view showing a third example of the wiring board 400. Specifically, Figure 7 is a cross-sectional view along the line F-F' in Figure 5.

[0075] In this example, since the rigid substrates 430a to 430c have the same structure, the explanation will focus on rigid substrate 430c as a representative example, and the illustrations and explanations of rigid substrates 430a and 430b will be omitted.

[0076] As shown in Figure 7, the rigid substrate 430c is a multilayer substrate including insulating layers 431A to 431C and a protective film 435.

[0077] The insulating layers 431A to 431C are stacked in order from top (i.e., in the positive Z-axis direction). Wiring layers are provided on the Z-axis positive surface of insulating layer 431A, between insulating layers 431A and 431B (the Z-axis positive surface of insulating layer 431B), between insulating layers 431B and 431C (the Z-axis negative surface of insulating layer 431B), and on the Z-axis negative surface of insulating layer 431C. In other words, the rigid substrate 430c is provided with four stacked wiring layers.

[0078] The protective film 435 is provided on the surface of the insulating layer 431A in the positive Z-axis direction and on the surface of the insulating layer 431C in the negative Z-axis direction. The protective film 435 is, for example, solder resist.

[0079] As shown in Figure 7, in this example, wiring 480 includes wiring 480A and 480B as portions provided on the rigid substrate 430c. Also in this example, wiring 490 includes wiring 490A to 490C as portions provided on the rigid substrate 430c.

[0080] The wiring 480A is provided on the Z-axis positive inner layer of the rigid substrate 430c (hereinafter referred to as the "first inner layer" for convenience), that is, on the Z-axis positive surface of the insulating layer 431B between the insulating layers 431A and 431B. For example, as shown in Figure 7, the wiring 480A is positioned in the center in the Y-axis direction.

[0081] The wiring 480B is provided on the inner layer of the rigid substrate 430c on the negative Z-axis side (hereinafter referred to as the "second inner layer" for convenience), that is, on the surface of the insulating layer 431B between the insulating layers 431B and 431C in the negative Z-axis direction. For example, as shown in Figure 7, the wiring 480B is located in the center in the Y-axis direction, similar to the wiring 480A.

[0082] The electrical connection between wiring 480A and 480B is achieved by the connector 481. The connector 481 may achieve the electrical connection between wiring 480A and 480B in any way. For example, the connector 481 may achieve the electrical connection between wiring 480A and 480B by via connection. Alternatively, the connector 481 may achieve the electrical connection between wiring 480A and 480B by copper inlay or the like.

[0083] The wiring 490A is provided on the outer layer of the rigid substrate 430c in the positive Z-axis direction, i.e., on the surface of the insulating layer 431A in the positive Z-axis direction. In the Y-axis direction, the wiring 490A is provided in a range that includes the entire area of ​​wirings 480A and 480B.

[0084] The wiring 490B is provided in the first inner layer of the rigid substrate 430c. The wiring 490B is positioned both between the wiring 480A and the positive Y-axis end of the rigid substrate 430c, and between the wiring 480A and the negative Y-axis end of the rigid substrate 430c. In other words, the wiring 490B is positioned so as to sandwich the wiring 480A in the Y-axis direction. For example, as shown in Figure 7, the wiring 490B is positioned such that the Y-axis position of the positive Y-axis end of the wiring 490B substantially coincides with the Y-axis position of the positive Y-axis end of the wiring 490A or wiring 490D. The same may apply to the position of the negative Y-axis end.

[0085] The wiring 490C is provided in the second inner layer of the rigid substrate 430c. The wiring 490C is positioned both between the wiring 480B and its positive Y-axis end, and between the wiring 480B and its negative Y-axis end. In other words, the wiring 490C is positioned so as to sandwich the wiring 480B in the Y-axis direction. For example, as shown in Figure 7, the wiring 490B is positioned such that the Y-axis position of its positive Y-axis end approximately coincides with the Y-axis position of the positive Y-axis end of the wiring 490A and wiring 490D. The same may apply to the position of the negative Y-axis end.

[0086] The wiring 490D is provided on the outer layer of the rigid substrate 430c in the negative Z-axis direction, i.e., on the surface of the insulating layer 431C in the negative Z-axis direction. The wiring 490D is provided in the Y-axis direction within a range that includes the entire area of ​​wirings 480A and 480B. For example, as shown in Figure 7, the wiring 490D is positioned such that its end in the positive Y-axis direction substantially coincides with the position of the end of wiring 490A in the positive Y-axis direction. The same may apply to the position in the negative Y-axis direction.

[0087] The electrical connection of wiring 490A to 490D is achieved by connection part 491. Connection part 491 may achieve the electrical connection of wiring 490A to 480D by any method. Connection part 481 may achieve the electrical connection between wiring 490A to 490D by via connection, for example. Alternatively, connection part 491 may achieve the electrical connection between wiring 490A to 490D by copper inlay or the like.

[0088] For example, as shown in Figure 7, the connection portion 491 is provided both on the negative Y-axis side and the positive Y-axis side of the wiring 480A, 480B and the connection portion 481 in the Y-axis direction.

[0089] Thus, in this example, wiring 480 is arranged so that it is sandwiched between wirings 490B and 490C in the Y-axis direction and between wirings 490A and 490D in the Z-axis direction. In addition, the connection portion 481 that connects the layers of wiring 480 may be arranged so that it is sandwiched between the connection portion 491 that connects the layers of wiring 490 in the Y-axis direction. This allows wiring 480 to be arranged in the rigid substrate 430c so that it is surrounded by wiring 490 when viewed from the X-axis direction. As a result, wiring 480 is electromagnetically shielded by wiring 490 and the connection portion 491, and as a result, the parasitic inductance component of wiring 490 (wirings 490A to 490D) in the rigid substrate 430c can be suppressed (cancelled). Thus, gate oscillation phenomena and current imbalances flowing to semiconductor switch elements SW caused by parasitic components of wiring 480 and 490 can be suppressed, and a wiring board 400 with higher reliability and operational stability can be realized.

[0090] [Fourth example of a wiring board] Next, a fourth example of the wiring board 400 according to this embodiment will be described with reference to Figures 8 to 10.

[0091] The following explanation will focus on the differences from the first to third examples described above, and explanations of content that is the same as or corresponds to the first to third examples may be omitted. In addition, in this example, the circuit diagram of the power converter 1 including the wiring board 400, the perspective view of the wiring board 400, and the top view of the wiring board 400 are the same as in the first example described above, so their illustration will be omitted, and the explanation will be based on Figures 1 to 3 of the first example described above.

[0092] Figures 8 to 10 are cross-sectional views showing a fourth example of the wiring board 400. Specifically, Figures 8 to 10 are cross-sectional views along lines A-A', B-B', and C-C' in Figure 2.

[0093] Furthermore, in the X-axis direction, the cross-sectional view of the soft substrate 420 between the pair of hard substrates 410a and the pair of hard substrates 410b, taken from a plane parallel to the Y and Z axes, is shown in the same way as in Figure 9, and therefore is omitted from the illustration. Also, the cross-sectional view of the wiring board 400 at the location where the soft substrate 420 is sandwiched between the pair of hard substrates 410a, taken from a plane parallel to the Y and Z axes, is shown in the same way as in Figure 10, and therefore is omitted from the illustration. Specifically, this is represented by a diagram in which the pair of hard substrates 410c, connection part 482c, and connection part 492c in Figure 10 are replaced by the pair of hard substrates 410a, connection part 482a, and connection part 492a, respectively. Also, the cross-sectional view of the wiring board 400 at the location where the soft substrate 420 is sandwiched between the pair of hard substrates 410b, taken from a plane parallel to the Y and Z axes, is shown in the same way as in Figure 10, and therefore is omitted from the illustration. Specifically, this is represented by a diagram in which each of the pair of rigid substrates 410c, connecting portion 482c, and connecting portion 492c in Figure 10 is replaced by a pair of rigid substrates 410b, connecting portion 482b, and connecting portion 492b.

[0094] As shown in Figures 8 to 10, the flexible substrate 420 includes insulating layers 421A to 421E.

[0095] The insulating layers 421A to 421E are stacked in order from top (i.e., in the positive Z-axis direction). Then, four stacked wiring layers are provided between insulating layers 421A and 421B (the surface of insulating layer 421B in the positive Z-axis direction), between insulating layers 421B and 421C (the surface of insulating layer 421C in the positive Z-axis direction), between insulating layers 421C and 421D (the surface of insulating layer 421C in the negative Z-axis direction), and between insulating layers 421D and 421E (i.e., the surface of insulating layer 421D in the negative Z-axis direction).

[0096] In this example, the wiring 480 includes wirings 480C and 480D as parts provided on the flexible substrate 420.

[0097] The wiring 480C is provided on the Z-positive inner layer of the soft substrate 420 (hereinafter referred to as the "first inner layer" for convenience), that is, on the Z-positive surface of the insulating layer 421C between the insulating layers 421B and 421C. For example, as shown in Figure 8, the wiring 480C is positioned approximately in the center of the first inner layer of the soft substrate 420 in the X-axis direction. Specifically, the wiring 480C may be positioned in the first inner layer such that its X-positive end extends to the X-axis position where the hard substrate 410a is located, and its X-negative end extends to the X-axis position where the hard substrate 410c is located. Alternatively, as shown in Figures 9 and 10, the wiring 480C may be positioned in the center of the Y-axis direction of the first inner layer.

[0098] The wiring 480D is provided on the inner layer of the soft substrate 420 in the negative Z-axis direction (hereinafter referred to as the "second inner layer" for convenience), that is, on the surface of the insulating layer 421C between insulating layers 421C and 421D in the negative Z-axis direction. For example, as shown in Figure 8, the wiring 480D is positioned approximately in the center in the X-axis direction of the second inner layer of the soft substrate 420. Specifically, the wiring 480D may be positioned in the second inner layer such that, like the wiring 480C, its end in the positive X-axis direction extends to the position in the X-axis direction where the hard substrate 410a is located, and its end in the negative X-axis direction extends to the position in the X-axis direction where the hard substrate 410c is located. Alternatively, as shown in Figures 9 and 10, for example, the wiring 480D may be positioned in the center in the Y-axis direction of the second inner layer, similar to the wiring 480C.

[0099] The electrical connection between the wiring 480C, 480D and the pair of rigid substrates 410a is achieved by the connector 482a. For example, as shown in Figure 8, the connector 482a connects the wiring 480C, 480D and the pair of rigid substrates 410a in the Z-axis direction at the X-axis negative ends of the wiring 480C, 480D.

[0100] The electrical connection between the wiring 480C, 480D and the pair of rigid substrates 410b is achieved by the connectors 482b. For example, as shown in Figure 8, two connectors 482b are provided in the center of the pair of rigid substrates 410b in the X-axis direction, and each connects the wiring 480C, 480D and the pair of rigid substrates 410b in the Z-axis direction.

[0101] The electrical connection between the wiring 480C, 480D and the pair of rigid substrates 410c is achieved by the connector 482c. For example, as shown in Figure 8, the connector 482c connects the wiring 480C, 480D and the pair of rigid substrates 410c in the Z-axis direction at the X-axis positive ends of the wiring 480C, 480D.

[0102] The connection portion 482a may achieve electrical connection between the wiring 480C, 480D and the pair of rigid substrates 410a by any means. For example, the connection portion 482a may achieve electrical connection between the wiring 480C, 480D and the pair of rigid substrates 410a by via connection. Alternatively, the connection portion 482a may achieve electrical connection between the wiring 480C, 480D and the pair of rigid substrates 410a by copper inlay or the like. The same may apply to the connection portions 482b and 482c.

[0103] The wiring 490 includes wiring 490E to 490H as a portion provided on the flexible substrate 420.

[0104] The wiring 490E is provided on the Z-positive outer layer of the flexible substrate 420, specifically on the Z-positive surface of the insulating layer 421B between the insulating layers 421A and 421B. The wiring 490E is provided in both the X-axis and Y-axis directions of the Z-positive outer layer of the flexible substrate 420, encompassing the entire regions of the wirings 480C and 480D. For example, as shown in Figure 8, the wiring 490E is provided in the Z-positive outer layer of the flexible substrate 420, extending from the X-positive end to the X-negative end.

[0105] The wiring 490F is provided in the first inner layer of the flexible substrate 420. The wiring 490F is positioned in the first inner layer of the flexible substrate 420 both between the wiring 480C and the positive X-axis end of the flexible substrate 420, and between the wiring 480C and the negative X-axis end of the flexible substrate 420. In other words, the wiring 490F is positioned in the X-axis direction of the first inner layer of the flexible substrate 420 so as to sandwich the wiring 480C. For example, as shown in Figure 8, the wiring 490F is positioned in the first inner layer of the flexible substrate 420 at both the positive X-axis end and the negative X-axis end. Also, the wiring 490F is positioned in the first inner layer of the flexible substrate 420 both between the wiring 480C and the positive Y-axis end of the flexible substrate 420, and between the wiring 480C and the negative Y-axis end of the flexible substrate 420. In other words, wiring 490F is positioned so as to sandwich wiring 480C in the Y-axis direction of the first inner layer of the soft substrate 420. For example, as shown in Figures 9 and 10, wiring 490F is positioned such that the Y-axis position of its end in the positive Y-axis direction approximately coincides with the Y-axis position of the end of wiring 490E and wiring 490H in the positive Y-axis direction. The same may apply to the position of the end in the negative Y-axis direction.

[0106] The wiring 490G is provided in the second inner layer of the flexible substrate 420. The wiring 490G is positioned in the second inner layer of the flexible substrate 420 both between the wiring 480D and the positive X-axis end of the flexible substrate 420, and between the wiring 480D and the negative X-axis end of the flexible substrate 420. In other words, the wiring 490G is positioned in the X-axis direction of the second inner layer of the flexible substrate 420 so as to sandwich the wiring 480D. For example, as shown in Figure 8, the wiring 490G is positioned in the first inner layer of the flexible substrate 420 at the positive X-axis end and the negative X-axis end, similar to the wiring 490F. Also, the wiring 490G is positioned in the second inner layer of the flexible substrate 420 both between the wiring 480D and the positive Y-axis end, and between the wiring 480D and the negative Y-axis end. In other words, wiring 490G is positioned so as to sandwich wiring 480D in the Y-axis direction of the second inner layer of the soft substrate 420. For example, as shown in Figures 9 and 10, wiring 490G is positioned such that, like wiring 490F, the Y-axis position of its positive Y-axis end approximately coincides with the Y-axis position of the positive Y-axis end of wiring 490E and wiring 490H. The same may apply to the position of the negative Y-axis end.

[0107] The wiring 490H is provided on the outer layer of the flexible substrate 420 in the negative Z-axis direction, i.e., on the surface of the insulating layer 421D in the negative Z-axis direction. Similar to the wiring 490E, the wiring 490H is provided in a range that includes the entire areas of wirings 480C and 480D in both the X-axis and Y-axis directions of the outer layer of the flexible substrate 420 in the negative Z-axis direction. For example, as shown in Figure 8, the wiring 490H is provided in a range that extends from the end in the positive X-axis direction to the negative X-axis direction end of the outer layer of the flexible substrate 420 in the negative Z-axis direction. Also, for example, as shown in Figures 9 and 10, the wiring 490H is positioned such that its end in the positive Y-axis direction substantially coincides with the position of the end of the wiring 490E in the positive Y-axis direction. The same may apply to the position in the negative Y-axis direction.

[0108] The electrical connection between the wiring 490E to 490H and the pair of rigid substrates 410a is achieved by the connection portion 492a. For example, as shown in Figure 8, the connection portion 492a connects the wiring 490E to 490H and the pair of rigid substrates 410a in the Z-axis direction at the X-axis negative ends of the wiring 490E and 490H. Alternatively, as shown in Figure 10, the connection portion 492a connects the wiring 490E to 490H and the pair of rigid substrates 410a in the Z-axis direction at both ends of the wiring 490E and 490H in the Y-axis positive and Y-axis negative directions.

[0109] The electrical connection between the wiring 490E, 490H and the pair of rigid substrates 410b is achieved by the connection portion 492b. For example, as shown in Figure 8, the connection portion 492b is provided at each of the X-axis ends of the pair of rigid substrates 410b, connecting the wiring 490E to 490H and the pair of rigid substrates 410b in the Z-axis direction. Alternatively, as shown in Figure 10, for example, the connection portion 492a connects the wiring 490E to 490H and the pair of rigid substrates 410b in the Z-axis direction at both ends of the wiring 490E and 490H in the positive and negative Y-axis directions.

[0110] The electrical connection between the wiring 490E-490H and the pair of rigid substrates 410c is achieved by the connector 492c. For example, as shown in Figure 8, the connector 492c connects the wiring 490E-490H and the pair of rigid substrates 410c in the Z-axis direction at the X-axis positive end of the wiring 490E and 490H. Also, for example, as shown in Figure 10, the connector 492c connects the wiring 490E-490H and the pair of rigid substrates 410c in the Z-axis direction at both ends of the wiring 490E and 490H in the Y-axis positive and Y-axis negative directions.

[0111] The connection portion 492a may achieve electrical connection between the wiring 490E to 490H and the pair of rigid substrates 410a by any means. For example, the connection portion 492a may achieve electrical connection between the wiring 490E to 490D and the pair of rigid substrates 410a by via connection. Alternatively, the connection portion 492a may achieve electrical connection between the wiring 490E to 490H and the pair of rigid substrates 410a by copper inlay or the like. The same may apply to the connection portions 492b and 492c.

[0112] Thus, in this example, wiring 480 is positioned so that it is sandwiched between wirings 490F and 490G in the X and Y directions, and between wirings 490E and 490H in the Z direction. This allows wiring 480 to be positioned on the flexible substrate 420 so that it is surrounded by wiring 490. As a result, wiring 480 is electromagnetically shielded by wiring 490, and consequently, the parasitic inductance component of wiring 490 (wirings 490E to 490H) on the flexible substrate 420 can be suppressed (cancelled). Therefore, gate oscillation phenomena and current imbalances flowing through semiconductor switch elements SW caused by parasitic components of wiring 480 and 490 can be suppressed, and a wiring board 400 with higher reliability and operational stability can be realized.

[0113] [Example 5 of a wiring board] Next, the wiring board 400 according to this embodiment will be described with reference to Figures 11 to 13.

[0114] The following explanation will focus on the differences from the first to fourth examples described above, and explanations of content that is the same as or corresponds to the first to fourth examples may be omitted. In addition, in this example, the circuit diagram of the power converter 1 including the wiring board 400, the perspective view of the wiring board 400, and the top view of the wiring board 400 are the same as in the first example described above, so their illustration will be omitted, and the explanation will be based on Figures 1 to 3 of the first example described above.

[0115] Figures 11 to 13 are cross-sectional views showing a fourth example of the wiring board 400. Specifically, Figures 11 to 13 are cross-sectional views along lines A-A', B-B', and C-C' in Figure 2.

[0116] Furthermore, in the X-axis direction, the cross-sectional view of the soft substrate 420 between the pair of hard substrates 410a and the pair of hard substrates 410b, taken from a plane parallel to the Y and Z axes, is shown in the same way as in Figure 12, and therefore is omitted from the illustration. Also, the cross-sectional view of the wiring board 400 at the location where the soft substrate 420 is sandwiched between the pair of hard substrates 410a, taken from a plane parallel to the Y and Z axes, is shown in the same way as in Figure 13, and therefore is omitted from the illustration. Specifically, this is represented by a diagram in which the pair of hard substrates 410c, connection part 483c, and connection part 493c in Figure 13 are replaced by the pair of hard substrates 410a, connection part 483a, and connection part 493a, respectively. Also, the cross-sectional view of the wiring board 400 at the location where the soft substrate 420 is sandwiched between the pair of hard substrates 410b, taken from a plane parallel to the Y and Z axes, is shown in the same way as in Figure 13, and therefore is omitted from the illustration. Specifically, this is represented by a diagram in which each of the pair of rigid substrates 410c, connecting portion 483c, and connecting portion 493c in Figure 10 is replaced by a pair of rigid substrates 410b, connecting portion 483b, and connecting portion 493b.

[0117] As shown in Figures 11 to 13, the flexible substrate 420 includes insulating layers 421A to 421E, similar to the fourth example described above, and is provided with four stacked wiring layers.

[0118] In this example, the wiring 480 includes wirings 480E and 480F as parts provided on the flexible substrate 420.

[0119] The wiring 480E is provided on the surface of the first inner layer of the flexible substrate 420, that is, on the insulating layer 421C between the insulating layers 421B and 421C. For example, as shown in Figure 11, the wiring 480E is provided in the first inner layer of the flexible substrate 420, in a range extending from the end in the positive X-axis direction to the end in the negative X-axis direction of the flexible substrate 420. Also, as shown in Figures 12 and 13, the wiring 480E is positioned in the central part in the Y-axis direction of the first inner layer of the flexible substrate 420 such that both ends in the positive Y-axis direction and the negative Y-axis direction are inward from both ends of the flexible substrate 420.

[0120] The wiring 480F is provided on the outer layer of the flexible substrate 420 in the negative X-axis direction, that is, on the surface of the insulating layer 421D between the insulating layers 421D and 421E in the negative Z-axis direction. For example, as shown in Figure 11, the wiring 480F is provided on the outer layer of the flexible substrate 420 in the negative X-axis direction, in a range extending from the end of the flexible substrate 420 in the positive X-axis direction to the end in the negative X-axis direction. Also, as shown in Figures 12 and 13, the wiring 480F is positioned in the center in the Y-axis direction on the outer layer of the flexible substrate 420 in the negative X-axis direction, such that both ends in the positive and negative Y-axis directions are inward from both ends of the flexible substrate 420. Alternatively, the wiring 480F may be positioned such that the positions of both ends in the positive and negative Y-axis directions substantially coincide with those of the wiring 480E.

[0121] The electrical connection between the wiring 480E, 480F and the pair of rigid substrates 410a is achieved by the connection portion 483a. For example, as shown in Figure 11 and Figure 13, the connection portion 483a is located closer to the positive X-axis direction than the center of the pair of rigid substrates 410a in the X-axis direction and at the center in the Y-axis direction, and each connects the wiring 480E, 480F and the pair of rigid substrates 410a in the Z-axis direction.

[0122] The electrical connection between the wiring 480E, 480F and the pair of rigid substrates 410b is achieved by the connectors 483b. For example, as shown in Figures 11 and 13, two connectors 483b are provided, aligned in the X-axis direction at the center of the pair of rigid substrates 410b in the Y-axis direction, and each connects the wiring 480E, 480F and the pair of rigid substrates 410b in the Z-axis direction.

[0123] The electrical connection between the wiring 480E, 480F and the pair of rigid substrates 410c is achieved by the connector 483c. For example, as shown in Figures 11 and 13, the connector 483c is located closer to the negative X-axis direction than the X-axis center of the pair of rigid substrates 410c and at the Y-axis center, and each connects the wiring 480E, 480F and the pair of rigid substrates 410c in the Z-axis direction.

[0124] The connection portion 483a may achieve electrical connection between the wiring 480E, 480F and the pair of rigid substrates 410a by any means. For example, the connection portion 483a may achieve electrical connection between the wiring 480E, 480F and the pair of rigid substrates 410a by via connection. Alternatively, the connection portion 483a may achieve electrical connection between the wiring 480E, 480F and the pair of rigid substrates 410a by copper inlay or the like. The same may apply to the connection portions 483b and 483c.

[0125] In this example, the wiring 490 includes wirings 490I and 490J as parts provided on the flexible substrate 420.

[0126] The wiring 490I is provided on the outer layer of the flexible substrate 420 in the positive X-axis direction, that is, on the Z-axis positive surface of the insulating layer 421B between the insulating layers 421A and 421B. For example, as shown in Figure 11, the wiring 490I is provided on the outer layer of the flexible substrate 420 in the positive X-axis direction, extending from the X-axis positive end to the X-axis negative end of the flexible substrate 420. Alternatively, as shown in Figures 12 and 13, for example, the wiring 490I is positioned in the center in the Y-axis direction of the outer layer of the flexible substrate 420 in the positive X-axis direction, such that both ends in the Y-axis positive and Y-axis negative directions are inward from both ends of the flexible substrate 420. The wiring 490I may also be positioned such that the positions of both ends in the Y-axis positive and Y-axis negative directions substantially coincide with the wirings 480E and 480F.

[0127] The wiring 490J is provided on the Z-axis negative surface of the insulating layer 421C between the insulating layers 421C and 421D in the second inner layer of the flexible substrate 420. For example, as shown in Figure 11, the wiring 490J is provided in the second inner layer of the flexible substrate 420, extending from the X-axis positive end to the X-axis negative end of the flexible substrate 420. Alternatively, as shown in Figures 12 and 13, the wiring 490J is positioned in the Y-axis central part of the second inner layer of the flexible substrate 420 such that both ends in the Y-axis positive and Y-axis negative directions are inward from both ends of the flexible substrate 420. The wiring 490I may also be positioned such that the positions of both ends in the Y-axis positive and Y-axis negative directions substantially coincide with the wirings 480E and 480F.

[0128] The electrical connection between the wiring 490I, 490J and the pair of rigid substrates 410a is achieved by the connector 493a. For example, as shown in Figures 11 and 13, the connector 493a is located closer to the negative X-axis direction than the center of the pair of rigid substrates 410a in the X-axis direction, and is provided at both ends of the wiring 490I, 490J in the Y-axis direction, connecting the wiring 490I to 490J and the pair of rigid substrates 410a in the Z-axis direction.

[0129] The electrical connection between the wiring 490I, 490J and the pair of rigid substrates 410b is achieved by the connectors 493b. For example, as shown in Figure 11, the connectors 493b are provided at both ends of the pair of rigid substrates 410b in the X-axis direction, and each connects the wiring 490I, 490J and the pair of rigid substrates 410b in the Z-axis direction. Alternatively, as shown in Figure 13, for example, the connectors 493b are provided at both ends of the wiring 490I, 490J in the Y-axis direction, and each connects the wiring 490I, 490J and the pair of rigid substrates 410b in the Z-axis direction.

[0130] The electrical connection between the wiring 490I-490J and the pair of rigid substrates 410c is achieved by the connector 493c. For example, as shown in Figures 11 and 13, the connector 493c is located closer to the positive X-axis direction than the center of the pair of rigid substrates 410c in the X-axis direction and at both ends of the wiring 490I and 490J in the Y-axis direction, connecting the wiring 490I-490J and the pair of rigid substrates 410c in the Z-axis direction.

[0131] The connection portion 493a may achieve electrical connection between the wiring 490I, 490J and the pair of rigid substrates 410a by any means. For example, the connection portion 493a may achieve electrical connection between the wiring 490I, 490D and the pair of rigid substrates 410a by via connection. Alternatively, the connection portion 493a may achieve electrical connection between the wiring 490I, 490J and the pair of rigid substrates 410a by copper inlay or the like. The same may apply to the connection portions 493b and 493c.

[0132] Thus, the wirings 480 and 490 are arranged alternately in the Z-axis direction, i.e., in the stacking direction of the wiring layers, on the flexible substrate 420. This allows for the cancellation of a portion of the parasitic inductance component of the wirings 480 and 490. As a result, the inductance per unit wiring length of the wirings 480 and 490 can be reduced. Therefore, gate oscillation phenomena and current imbalances flowing through semiconductor switch elements SW caused by parasitic components of the wirings 480 and 490 can be suppressed, resulting in a wiring substrate 400 with higher reliability and operational stability.

[0133] [Example 6 of a wiring board] Next, with reference to Figure 14, a sixth example of the wiring board 400 according to this embodiment will be described.

[0134] The following explanation will focus on the differences from the first to fifth examples described above, and explanations of content that is the same as or corresponds to the first to fifth examples may be omitted.

[0135] Figure 14 is a circuit diagram showing an example of a power converter 1, including a sixth example of the wiring board 400.

[0136] Note that, unlike Figures 1 and 4, Figure 14 omits the main circuit and only shows the arm section 10. The same applies to Figures 15 to 18, which will be discussed later.

[0137] As shown in Figure 14, this example differs from the second example described above in that common mode choke coils 495a to 495c are added, but is otherwise the same as the second example described above.

[0138] The wiring board 400 includes common mode choke coils 495a to 495c.

[0139] The common mode choke coil 495a is provided so as to straddle the wiring 480a connecting electrode 450a and electrode 460a, and the wiring 490a connecting electrode 450b and electrode 470a. Specifically, the primary coil of the common mode choke coil 495a is positioned so as to be inserted into the wiring 480a, and the secondary coil of the common mode choke coil 495a is positioned so as to be inserted into the wiring 490a. For example, as shown in Figure 14, the common mode choke coil 495a is positioned on the rigid substrate 430a.

[0140] The common mode choke coil 495b is provided so as to span the wiring 480b connecting electrode 450a and electrode 460b, and the wiring 490b connecting electrode 450b and electrode 470b. Specifically, the primary coil of the common mode choke coil 495b is placed on wiring 480b, and the secondary coil of the common mode choke coil 495b is placed on wiring 490b. For example, as shown in Figure 14, the common mode choke coil 495b is placed on the rigid substrate 430b.

[0141] The common mode choke coil 495c is provided so as to span the wiring 480c connecting electrode 450a and electrode 460c, and the wiring 490c connecting electrode 450b and electrode 470c. Specifically, the primary coil of the common mode choke coil 495c is placed on wiring 480c, and the secondary coil of the common mode choke coil 495c is placed on wiring 490c. For example, as shown in Figure 14, the common mode choke coil 495c is placed on the rigid substrate 430c.

[0142] As described above, in this example, common-mode choke coils 495a to 495c are provided so as to span wirings 480 and 490. This suppresses the common-mode current between semiconductor modules 100a to 100c, thereby reducing the lateral current (circulating current) in wirings 480 and 490 caused by variations in the characteristics of the semiconductor switch elements SW for each semiconductor module 100a to 100c. Therefore, it is possible to suppress the deterioration of the switching performance of the semiconductor switch elements SW, as well as gate oscillation phenomena and current imbalances between semiconductor modules 100a to 100c. Thus, a wiring board 400 with higher reliability and operational stability can be realized.

[0143] [Example 7 of a wiring board] Next, with reference to Figure 15, a seventh example of the wiring board 400 according to this embodiment will be described.

[0144] The following explanation will focus on the differences from the above-mentioned Examples 1 through 6, and may omit explanations of content that is the same as or corresponds to Examples 1 through 6.

[0145] Figure 15 is a circuit diagram showing an example of a power converter 1, including a seventh example of the wiring board 400.

[0146] As shown in Figure 15, this example differs from the second example described above in that magnetic cores 496a to 496c are added, but is otherwise the same as the second example described above.

[0147] The wiring board 400 includes magnetic cores 496a to 496c (an example of magnetic cores for common mode chokes).

[0148] For example, as shown in Figure 15, the magnetic core 496a has a substantially annular shape and is provided so as to surround the wiring 480a connecting electrode 450a and electrode 460a, and the wiring 490a connecting electrode 450b and electrode 470a. For example, as shown in Figure 15, the magnetic core 496a is placed on the hard substrate 430a.

[0149] For example, as shown in Figure 15, the magnetic core 496b has a substantially annular shape and is provided so as to surround the wiring 480b connecting electrode 450a and electrode 460b, and the wiring 490b connecting electrode 450b and electrode 470b. For example, as shown in Figure 15, the magnetic core 496b is placed on the hard substrate 430b.

[0150] For example, as shown in Figure 15, the magnetic core 496c has a substantially annular shape and is provided so as to surround the wiring 480c connecting electrode 450a and electrode 460c, and the wiring 490c connecting electrode 450b and electrode 470c. For example, as shown in Figure 15, the magnetic core 496c is placed on the hard substrate 430c.

[0151] The magnetic cores 496a to 496c may be configured as a single unit, or they may be configured in a separable form from the viewpoint of ensuring mechanical strength and ease of mounting on the wiring board 400.

[0152] In this example, magnetic cores 496a to 496c are provided so as to surround wiring 480 and 490. This allows for the suppression of common-mode current, similar to the common-mode choke coils 495a to 495c in the sixth example described above. As a result, the lateral current (circulating current) in wiring 480 and 490 caused by variations in the characteristics of semiconductor switch elements SW for each semiconductor module 100a to 100c can be reduced. Therefore, it is possible to suppress gate oscillation phenomena and current imbalances for each semiconductor module 100a to 100c while suppressing a decrease in the switching performance of the semiconductor switch elements SW. Thus, a wiring board 400 with higher reliability and operational stability can be realized.

[0153] [Example 8 of a wiring board] Next, with reference to Figure 16, an eighth example of the wiring board 400 according to this embodiment will be described.

[0154] The following explanation will focus on the differences from the above-mentioned Examples 1 through 7, and may omit explanations of content that is the same as or corresponds to those examples 1 through 7.

[0155] Figure 16 is a circuit diagram showing an example of a power converter 1, including an eighth example of the wiring board 400.

[0156] As shown in Figure 16, this example differs from the second example described above in that magnetic cores 497a and 497b are added, but is otherwise the same as the second example described above.

[0157] The wiring board 400 includes magnetic cores 497a and 497b (an example of magnetic cores for common-mode chokes).

[0158] For example, as shown in Figure 16, the magnetic core 497a has a substantially annular shape and is provided so as to surround the soft substrate 440a on which the wiring 480 (wiring 480a) and wiring 490 (wiring 490a) are arranged. The magnetic core 497a is held and fixed to at least one of the hard substrates 430a and 430b, for example. Any form of holding mechanism (fixing mechanism) between the magnetic core 497a and the hard substrates 430a and 430b may be adopted. For example, the magnetic core 497a is provided with a notch, and the hard substrates 430a and 430b are inserted into the notch, thereby holding and fixing the magnetic core 497a.

[0159] Furthermore, some of the wirings 480b and 490b may be placed on the flexible substrate 440a.

[0160] For example, as shown in Figure 16, the magnetic core 497b has a substantially annular shape and is provided so as to surround the soft substrate 440a on which the wiring 480 (wiring 480c) and wiring 490 (wiring 490c) are arranged. The magnetic core 497b is held and fixed to at least one of the hard substrates 430b and 430c, for example. Any form of holding mechanism (fixing mechanism) between the magnetic core 497a and the hard substrates 430b, 430c may be adopted. For example, the magnetic core 497b is provided with a notch, and the hard substrates 430b, 430c are inserted into the notch, thereby holding and fixing the magnetic core 497b.

[0161] Furthermore, some of the wiring 480b and 490b may be placed on the flexible substrate 440b.

[0162] The magnetic cores 497a and 497b may be configured as a single unit, similar to the magnetic cores 496a to 496c in the seventh example described above, or they may be configured in a separable form.

[0163] Thus, in this example, magnetic cores 497a and 497b are provided so as to surround the soft substrates 440a and 440b on which wirings 480 and 490 are provided. As a result, as in the 6th and 7th examples described above, common-mode current can be suppressed, and consequently, the lateral current (circulating current) in wirings 480 and 490 caused by variations in the characteristics of semiconductor switch elements SW for each semiconductor module 100a to 100c can be reduced. Therefore, it is possible to suppress the deterioration of the switching performance of the semiconductor switch elements SW, as well as gate oscillation phenomena and current imbalances for each semiconductor module 100a to 100c. Thus, a wiring board 400 with higher reliability and operational stability can be realized.

[0164] [Example 9 of a wiring board] Next, with reference to Figure 17, a ninth example of the wiring board 400 according to this embodiment will be described.

[0165] The following explanation will focus on the differences from the above-mentioned Examples 1 through 8, and may omit explanations of content that is the same as or corresponds to those examples 1 through 8.

[0166] Figure 17 is a circuit diagram showing an example of a power converter 1, including a ninth example of the wiring board 400.

[0167] As shown in Figure 17, this example differs from the second example described above in that resistors 498a to 498c are added, but is otherwise the same as the second example described above.

[0168] The wiring board 400 includes resistors 498a to 498c (an example of the first resistor).

[0169] The resistor 498a is positioned by being inserted into the wiring 480a that connects electrodes 450a and 460a. For example, as shown in Figure 17, the resistor 498a is positioned on the rigid substrate 430a.

[0170] The resistor 498b is positioned by being inserted into the wiring 480b that connects electrodes 450a and 460b. For example, as shown in Figure 17, the resistor 498b is positioned on the rigid substrate 430b.

[0171] The resistor 498c is positioned by being inserted into the wiring 480c that connects electrodes 450a and 460c. For example, as shown in Figure 17, the resistor 498c is positioned on the rigid substrate 430c.

[0172] The resistance values ​​of resistors 498a to 498c can be set as appropriate and may be approximately the same as each other, or at least some of them may be different.

[0173] In this example, resistors 498a to 498c are placed on wiring 480. This suppresses current imbalances caused by variations in the characteristics of semiconductor switch elements SW for each semiconductor module 100a to 100c. Furthermore, when the current imbalance is at a negligible level, it is possible to suppress lateral currents (circulating currents) between semiconductor modules 100a to 100c. This is particularly suitable when there is not enough space to mount the magnetic cores 496a to 496c in the seventh example or the magnetic cores 497a and 497b in the eighth example described above.

[0174] [Example 10 of a wiring board] Next, with reference to Figure 18, a tenth example of the wiring board 400 according to this embodiment will be described.

[0175] The following explanation will focus on the differences from the above-mentioned Examples 1 through 9, and may omit explanations of content that is the same as or corresponds to those examples 1 through 9.

[0176] Figure 18 is a circuit diagram showing an example of a power converter 1, including a 10th example of the wiring board 400.

[0177] As shown in Figure 18, this example differs from the second example described above in that resistors 499a to 499c are added, but is otherwise the same as the second example described above.

[0178] The wiring board 400 includes resistors 499a to 499c (an example of a second resistor).

[0179] The resistor 499a is positioned by being inserted into the wiring 490a that connects electrode 450b and electrode 470a. For example, as shown in Figure 18, the resistor 499a is positioned on the rigid substrate 430a.

[0180] The resistor 499b is positioned by being inserted into the wiring 490b that connects electrodes 450b and 470b. For example, as shown in Figure 18, the resistor 499b is positioned on the rigid substrate 430b.

[0181] The resistor 499c is positioned by being inserted into the wiring 490c that connects electrode 450b and electrode 470c. For example, as shown in Figure 18, the resistor 499c is positioned on the rigid substrate 430c.

[0182] The resistance values ​​of resistors 499a to 499c can be set as appropriate and may be approximately the same as each other, or at least some of them may be different.

[0183] In this example, resistors 499a to 499c are placed on wiring 490. This suppresses current imbalance caused by variations in the characteristics of semiconductor switch elements SW for each semiconductor module 100a to 100c. Furthermore, when the current imbalance is at a negligible level, it is possible to suppress lateral current (circulating current) between semiconductor modules 100a to 100c. This is particularly suitable when there is not enough space to mount the magnetic cores 496a to 496c in the seventh example or the magnetic cores 497a and 497b in the eighth example described above.

[0184] [Example 11 of a wiring board] Next, an eleventh example of a wiring board according to this embodiment will be described.

[0185] In this example, the circuit diagram of the power converter 1, including the wiring board 400, is the same as in the first example described above, so its illustration is omitted, and the explanation will be given using Figure 1.

[0186] This example differs from the first example described above in that the structure of electrode 450 and circuit 500 is specified, but is otherwise the same as the first example described above.

[0187] In this example, coaxial connectors are used to connect wiring 480 and 490 to circuit 500. The coaxial connectors are, for example, BNC connectors. For example, the electrode 450 connected to wiring 480 and 490 is the jack (female) of the coaxial connector, and the end of circuit 500 connected to electrode 450 is the plug (male) of the coaxial connector. This allows the plug of the coaxial connector at the end of circuit 500 to be inserted into the jack of the coaxial connector corresponding to electrode 450, thereby connecting wiring 480 and 490 to circuit 500.

[0188] Specifically, wiring 480 is connected to the central circuit body (internal conductor) of the coaxial connector (jack), and wiring 490 is connected to the outer conductor that surrounds the central circuit body of the coaxial connector (jack). In other words, the central circuit body (internal conductor) of the coaxial connector (jack), which acts as electrode 450, corresponds to electrode 450a, and the outer conductor of the coaxial connector (jack), which acts as electrode 450, corresponds to electrode 450b.

[0189] The circuit 500 has a coaxial structure including a central circuit body (internal conductor) and an outer conductor surrounding the circuit body. In other words, the central circuit body corresponds to circuit 500a, and the outer conductor surrounding the circuit body corresponds to circuit 500b. Circuit 500 is, for example, a coaxial cable.

[0190] Thus, in this example, a coaxial structure is employed for the electrode 450 and the circuit 500. In this example, the circuit 500 and the wirings 480 and 490 may be connected to each other via a coaxial connector. Specifically, the circuit 500a, which is the main body of the circuit 500, is connected to the wiring 480 which is connected to the main body of the coaxial connector including the electrode 450a, and the circuit 500b, which is the outer conductor of the circuit 500, is connected to the wiring 490 which is connected to the outer conductor of the coaxial connector including the electrode 450b. This makes it possible to reduce the parasitic inductance component of the electrode 450 and the circuit 500 in the wiring path from the drive circuit of the drive circuit board 300 to each semiconductor switch element SW of the semiconductor modules 100a to 100c. Therefore, as in the third and fourth examples described above, a wiring board 400 with higher reliability and operational stability can be realized.

[0191] [Example 12 of a wiring board] Next, with reference to Figures 19 and 20, a twelfth example of the wiring board 400 will be described.

[0192] The following explanation will focus on the differences from the above-mentioned Examples 1 through 10, and may omit explanations of content that is the same as or corresponds to those examples 1 through 10.

[0193] Figure 19 is a top view showing the wiring pattern 480WP of the 11th example of the wiring board 400. Specifically, it is a diagram showing an example of the wiring pattern 480WP of wiring 480. Figure 20 is a top view showing the wiring pattern 480WP_C related to a comparative example.

[0194] In this example, the circuit diagram of the power converter 1, including the wiring board 400, is the same as in the first example described above, so its illustration is omitted, and the explanation will be based on Figure 1.

[0195] The wiring pattern 480WP electrically connects electrode 450a to electrodes 460a to 460c. The wiring pattern 480WP is provided, for example, on the flexible substrate 420. Alternatively, the wiring pattern 480WP may be provided so as to span both the flexible substrate 420 and the rigid substrates 410a to 410c.

[0196] As shown in Figure 17, electrodes 460a to 460c are positioned such that their positions in the Y-axis direction are approximately the same, and the distance La between electrodes 460a and 460b and the distance Lc between electrodes 460b and 460c are approximately the same.

[0197] Electrode 450a is positioned such that its position in the X-axis direction is approximately the same as that of electrode 460b.

[0198] A slit 484 is provided in the wiring pattern 480WP. This electrically isolates the area around the slit 484. Therefore, the wiring length between electrode 450a and electrodes 460a to 460c can be adjusted to bypass the slit 484.

[0199] In this example, the slit 484 is provided so that the path between electrode 450a and electrode 460b becomes two paths, passing through both electrodes 460a and 460c. In addition, in this example, the slit 484 is provided so that the wiring length WLa1 between electrode 450a and electrode 460a, the wiring length WLc1 between electrode 450a and electrode 460c, the wiring length WLab1 between electrodes 460a and 460b, and the wiring length WLbc1 between electrodes 460b and 460c are approximately the same.

[0200] Therefore, the following relationship (1) holds between the parasitic inductance component Lpa in the path between electrode 450a and electrode 460a and the parasitic inductance component Lpc in the path between electrode 450a and electrode 460c.

[0201] Lpa ≈ Lpc ···(1)

[0202] Furthermore, the two paths between electrodes 450a and 460b, one passing through electrode 460a and the other through electrode 460c, are approximately the same length and are twice as long as the path between electrodes 450a and 460a. Therefore, the parasitic inductance component Lpb of the path between electrodes 450a and 460b is given by the following equation (2).

[0203] Lpb≒2 Lpa / 2 Lpa=Lpa (2)

[0204] Therefore, as can be seen from equations (1) and (2), in this example, by providing the slit 484, the inductance components of the paths between electrode 450a and electrodes 460a to 460c can be made approximately equal.

[0205] For example, if semiconductor module 100b is omitted and the wiring board 400 drives two semiconductor modules 100a and 100c, the wiring lengths WLa1 and WLc1 can be made approximately the same relatively easily, as shown in Figure 20. However, if there are three or more semiconductor modules driven by the wiring board 400, attempting to make the wiring lengths the same solely by the geometric arrangement of electrodes 460a to 460c may lead to an increase in the mounting area of ​​the wiring pattern 480WP and an increase in unnecessary wiring lengths.

[0206] In contrast, in this example, a slit 484 is provided in the wiring pattern 480WP of wiring 480 so that the inductance components of the paths between electrode 450a and electrodes 460a to 460c are approximately the same. This makes it possible to suppress an increase in the parasitic inductance component caused by wiring 480 while suppressing an unintentional increase in the mounting area and wiring length of wiring 480.

[0207] [Other examples of circuit boards] The first to eleventh examples of the wiring boards described above may be combined as appropriate.

[0208] For example, the arrangement structure of wiring 480,490 in the rigid substrates 430a to 430c of the third example described above may be applied to the rigid substrates 410a to 410c of the first, eleventh, and twelfth examples described above.

[0209] Furthermore, for example, the arrangement structure of the wirings 480 and 490 in the flexible substrate 420 of the fourth and fifth examples described above may also be applied to the flexible substrates 440a and 440b of the second, third, sixth to tenth examples described above.

[0210] Furthermore, for example, the arrangement structure of the wiring 480, 490 in the flexible substrate 420 of the fifth example described above may also be applied to the rigid substrates 410a to 410c or rigid substrates 430a to 430c of the first, second, fourth, sixth to twelfth examples described above or their modified versions.

[0211] Furthermore, for example, the common mode choke coils 495a to 495c of the sixth example described above may be applied to the wiring 480 and 490 of the first, eleventh, and twelfth examples and their modified versions described above. The same may apply to the magnetic cores 496a to 496c of the seventh example described above, the resistors 498a to 498c of the ninth example described above, and the resistors 499a to 499c of the tenth example described above.

[0212] Furthermore, for example, the magnetic cores 497a and 497b of the eighth example described above may be applied to the soft substrates 420 of the first, eleventh, and twelfth examples and their modified forms described above.

[0213] Furthermore, for example, the ninth example or its variations described above, and the tenth example or its variations described above, may be combined. In other words, the wiring board 400 may be provided with both resistors 498a to 498c and resistors 499a to 499c.

[0214] Furthermore, for example, the structure of the electrode 450 and the circuit 500 in the 11th example described above may be applied to the 2nd to 10th and 12th examples described above, or their modified versions.

[0215] Furthermore, for example, the slit 484 of the wiring pattern 480WP in the 12th example described above may be applied to the wiring pattern 480 of the 2nd to 11th examples and their modified versions described above.

[0216] Furthermore, the first to eleventh examples of the wiring boards described above, as well as their variations, may be modified or altered as appropriate.

[0217] For example, in the first to eleventh examples and their variations described above, the number of semiconductor switch elements SW (corresponding semiconductor modules) connected in parallel to the drive target by the drive circuit board 300 and the wiring board 400 may be two or four or more. In this case, by adopting the same configuration and structure as the first to eleventh examples and their variations described above, similar functions and effects can be achieved.

[0218] Furthermore, for example, in the 12th example and its modified form described above, the number of semiconductor switch elements SW (corresponding semiconductor modules) connected in parallel to the drive circuit board 300 and the wiring board 400 may be four or more. In this case, by adopting the same configuration and structure (slit 484) as in the 12th example and its modified form described above, similar functions and effects can be achieved.

[0219] Furthermore, for example, in the third example and its modified form described above, the number of wiring layers stacked on the rigid substrates 410a to 410c or rigid substrates 430a to 430c may be three or five or more. In this case, by adopting the same configuration and structure as the third example and its modified form described above (a stacked structure of wiring 480, 490), similar effects and benefits can be achieved.

[0220] Furthermore, in the third example and its modified form described above, in order to electromagnetically shield the wiring 480, other electrical connection methods may be used for the wiring 490 of each wiring layer of the hard substrates 430a to 430c and the soft substrates 440a and 440b instead of the connection portion 491. For example, similar effects can be obtained by employing an electrical connection method such as plating the ends of the soft substrates 440a and 440b and the hard substrates 430a to 430c and connecting them to the wiring 490 of each wiring layer.

[0221] Furthermore, in the fourth example and its modified form described above, in order to electromagnetically shield the wiring 480, other electrical connection methods may be used for the wiring 490 of each wiring layer of the hard substrates 410a to 410c and the soft substrate 420 instead of the connection parts 492a to 492c. For example, the same effect can be obtained by employing an electrical connection method such as plating the edges of the soft substrate 420 and the hard substrates 410a to 410c and connecting them to the wiring 490 of each wiring layer.

[0222] Furthermore, in the fourth example, the fifth example, and its modified form described above, the number of wiring layers laminated on the soft substrate 420 or the soft substrates 440a, 440b may be three or five or more. In this case, by adopting the same configuration and structure as the fourth example and its modified form described above (a laminated structure of wiring 480, 490), similar effects and benefits can be achieved.

[0223] Furthermore, for example, in the 11th example and its modified form described above, the circuit 500 may be replaced with a structure consisting of a flexible substrate and wiring corresponding to circuits 500a and 500b on the flexible substrate, instead of a coaxial structure. In this case, the wiring on the flexible substrate corresponding to circuits 500a and 500b may be arranged in the same configuration as the wiring 480 and 490 on the flexible substrate 420 in the 3rd example described above. This will produce the same functions and effects as in the case of a coaxial structure.

[0224] Furthermore, in the first to twelfth examples and their variations described above, the wiring board 400 may be configured to drive multiple sets of parallel-connected semiconductor modules (semiconductor switch elements SW). This is particularly suitable when, for example, a 2-in-1 package semiconductor module containing two semiconductor switch elements SW corresponding to upper and lower arms is used. In this case, multiple sets of electrodes 460a to 460c, electrodes 470a to 470c, and wiring 480 and 490 for driving a specific set of multiple semiconductor modules are mounted on the rigid or flexible substrate of the wiring board 400.

[0225] [Effect] Next, the operation of the wiring board 400 according to this embodiment will be described.

[0226] In this embodiment, the wiring board 400 comprises a pair of rigid substrates (e.g., rigid substrates 410a to 410c), a flexible substrate (e.g., flexible substrate 420), a first electrode (e.g., electrodes 460a to 460c), a second electrode (e.g., electrodes 470a to 470c), a first wiring (e.g., wiring 480), and a second wiring (e.g., wiring 490). Specifically, a pair of rigid substrates is provided for each of a plurality of semiconductor elements (e.g., semiconductor switch elements SW) connected in parallel. The flexible substrate is provided such that at least a portion of it is sandwiched between all the pairs of rigid substrates. The first electrode connects the control terminal of the semiconductor element to the rigid substrate or the flexible substrate. The second electrode connects the reference potential terminal of the semiconductor element to the rigid substrate or the flexible substrate. Furthermore, the first wiring is provided on the flexible substrate in at least a portion of it, connecting the first electrodes of each of the multiple semiconductor elements in parallel. The second wiring is also provided on the flexible substrate in at least a portion of it, connecting the second electrodes of each of the multiple semiconductor elements in parallel.

[0227] In this embodiment, the wiring board 400 comprises a rigid substrate (e.g., rigid substrates 430a to 430c), a flexible substrate (e.g., flexible substrates 440a, 440b), a first electrode (e.g., electrodes 460a to 460c), a second electrode (e.g., electrodes 470a to 470c), a first wiring (e.g., wiring 480), and a second wiring (e.g., wiring 490). Specifically, a rigid substrate is provided for each of the multiple semiconductor elements (e.g., semiconductor switch elements SW) connected in parallel. The flexible substrates connect the rigid substrates to each other. The first electrode connects the control terminal of the semiconductor element to the rigid substrate. The second electrode connects the reference potential terminal of the semiconductor element to the rigid substrate. The first wiring is provided on the rigid and flexible substrates and connects the first electrode of each of the multiple semiconductor elements in parallel. Furthermore, the second wiring is provided on both the rigid and flexible substrates, connecting the second electrodes of each of the multiple semiconductor elements in parallel. The flexible substrate then connects all the rigid substrates for each of the multiple semiconductor elements.

[0228] This allows the wiring length between the drive circuit and the control terminals of each semiconductor element to be adjusted by the wiring pattern on the rigid and flexible substrates. Therefore, the degree of freedom in the wiring pattern can suppress the increase in wiring length when aligning the wiring length between the drive circuit and the control terminals of each semiconductor element. As a result, the performance of the semiconductor elements can be brought out to the desired level, and the occurrence of gate oscillation can be suppressed. In addition, since connectors are not used for interconnecting the rigid substrates, the occurrence of connection failure problems can be suppressed, and the height of the wiring board 400 can be reduced. Thus, a wiring board 400 with higher reliability and operational stability can be realized. Furthermore, since the manufacturing process for connector mating is not required, labor in assembly work can be reduced, manufacturing efficiency can be improved, and manufacturing costs can be reduced.

[0229] Furthermore, in this embodiment, the rigid substrate may have three or more wiring layers. The first wiring may be provided in the inner layer of the three or more wiring layers in the rigid substrate. The second wiring may be provided in both outer layers of the three or more wiring layers in the rigid substrate, as well as in the inner layer so as to sandwich the first wiring between them.

[0230] As a result, the first wiring is electromagnetically shielded by the second wiring, and consequently, the parasitic inductance component of the second wiring on the rigid substrate can be suppressed (cancelled). Therefore, gate oscillation phenomena and current imbalances flowing through semiconductor elements caused by parasitic components in the first and second wirings can be suppressed, and a wiring board 400 with higher reliability and operational stability can be realized.

[0231] Furthermore, in this embodiment, the wiring board 400 may have three or more wiring layers. The first wiring may be provided in the inner layer of the three or more wiring layers in the flexible board. The second wiring may be provided on both outer layers of the three or more wiring layers in the flexible board, as well as in the inner layer so as to sandwich the first wiring between them.

[0232] As a result, the first wiring is electromagnetically shielded by the second wiring, and consequently, the parasitic inductance component of the second wiring on the flexible substrate can be suppressed (cancelled). Therefore, gate oscillation phenomena and current imbalances flowing through the semiconductor switch element SW caused by parasitic components in the first and second wirings can be suppressed, and a wiring board 400 with higher reliability and operational stability can be realized.

[0233] Furthermore, in this embodiment, the first wiring and the second wiring may be alternately stacked on at least one of the rigid substrate and the flexible substrate.

[0234] This allows for the cancellation of a portion of the parasitic inductance components of the first and second wirings. As a result, the inductance per unit wiring length of the first and second wirings can be reduced. Therefore, gate oscillation phenomena and current imbalances flowing through the semiconductor switch element SW caused by parasitic components in the first and second wirings can be suppressed, resulting in a wiring board 400 with higher reliability and operational stability.

[0235] Furthermore, in this embodiment, the wiring board 400 may also include a common mode choke coil (for example, common mode choke coils 495a to 495c) which includes a primary coil provided on the first wiring and a secondary coil provided on the second wiring.

[0236] This suppresses common-mode current between semiconductor elements, thereby reducing lateral current (circulating current) in the first and second wirings caused by variations in the characteristics of each semiconductor element. As a result, it is possible to suppress gate oscillation phenomena and current imbalances between semiconductor elements while suppressing a decrease in the switching performance of the semiconductor elements. Therefore, it is possible to realize a wiring board 400 with higher reliability and operational stability.

[0237] Furthermore, in this embodiment, the wiring board 400 may also include magnetic cores for common mode chokes (for example, magnetic cores 496a to 496c or magnetic cores 497a, 497b) that surround the first and second wirings.

[0238] This allows for the suppression of common-mode current, similar to a common-mode choke coil. As a result, it reduces the lateral current (circulating current) in the first and second wirings caused by variations in the characteristics of each semiconductor element. Therefore, it is possible to suppress gate oscillation phenomena and current imbalances between semiconductor elements while suppressing a decrease in the switching performance of the semiconductor elements. Thus, a wiring board 400 with higher reliability and operational stability can be realized.

[0239] Furthermore, in this embodiment, the wiring board 400 may have magnetic cores (for example, magnetic cores 497a, 497b) that have notches, and these notches may be used to fix the board to the rigid substrate.

[0240] This allows the magnetic core to be efficiently fixed to the wiring board 400 with a simple structure.

[0241] Furthermore, in this embodiment, the wiring board 400 may also include first resistors (for example, resistors 498a to 498c) provided in the first wiring.

[0242] This makes it possible to suppress current imbalances caused by variations in the characteristics of each semiconductor element. Furthermore, when the current imbalance is at a negligible level, it is possible to suppress lateral currents (circulating currents) between semiconductor elements.

[0243] Furthermore, in this embodiment, the wiring board 400 may also include a second resistor (for example, resistors 499a to 499c) provided on the second wiring.

[0244] This makes it possible to suppress current imbalances caused by variations in the characteristics of each semiconductor element. Furthermore, when the current imbalance is at a negligible level, it is possible to suppress lateral currents (circulating currents) between semiconductor elements.

[0245] Furthermore, in this embodiment, the wiring board 400 may also include a third electrode (for example, electrode 450a) that connects a drive circuit for driving a plurality of semiconductor elements to the first wiring. The third electrode may also have a coaxial structure.

[0246] This reduces the parasitic inductance component of the third electrode in the wiring path from the drive circuit to the multiple semiconductor elements. As a result, gate oscillation phenomena and current imbalances flowing through the semiconductor elements caused by parasitic components are suppressed, enabling the realization of a wiring board 400 with higher reliability and operational stability.

[0247] Furthermore, in this embodiment, the wiring board 400 may be connected to the third electrode and the drive circuit by a coaxial circuit (for example, circuit 500a).

[0248] This reduces the parasitic inductance component in the circuit between the third electrode and the drive circuit, which is part of the wiring path from the drive circuit to multiple semiconductor elements. As a result, gate oscillation phenomena and current imbalances in the semiconductor elements caused by parasitic components are suppressed, enabling the realization of a wiring board 400 with higher reliability and operational stability.

[0249] Furthermore, in this embodiment, the wiring board 400 may include a third electrode (e.g., electrode 450a) that connects a drive circuit for driving a plurality of semiconductor elements to the first wiring. In addition, slits (e.g., slit 484) may be provided in the wiring pattern (e.g., wiring pattern 480WP) of the first wiring so that the parasitic impedance is equal between the third electrode and the parallel connection path between the first electrode for each of the plurality of semiconductor elements.

[0250] This makes it possible to suppress an unintentional increase in the mounting area and wiring length of wiring 480, while also suppressing an increase in the parasitic inductance component caused by wiring 480.

[0251] Furthermore, in this embodiment, the wiring board 400 may have a first electrode, a second electrode, a first wiring, and a second wiring mounted on each of multiple sets, each of which consists of multiple semiconductor elements.

[0252] As a result, for example, when a semiconductor module in a 2-in-1 package containing two semiconductor elements in upper and lower arms is used, the wiring board 400 can drive multiple sets of multiple semiconductor elements connected in parallel.

[0253] Although embodiments have been described in detail above, this disclosure is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist described in the claims. [Explanation of Symbols]

[0254] 1. Power converter 10 Arm section 20 Leg Section 100a~100c Semiconductor Module 200a, 200b wiring 300 Drive Circuit Board 400 Wiring boards 410a~410c Hard substrate 420 Soft substrate 421A~421E Insulating layer 430a~430c Hard board 431A~431C Insulating layer 435 Protective film 440a,440b Soft substrate 450,450a,450b electrode 460a~460c electrode 470a~470c electrode 480 Wiring 480a~480c wiring 480A, 480B wiring 480C and 480D wirings 480E and 480F wirings 480WP wiring pattern 481 connection part 482a to 482c connection parts 483a to 483c connection parts 484 slit [[ID=X]]490 wiring 490a to 490c wirings 490A to 490D wirings 490E to 490H wirings 490I and 490J wirings 491 connection part 492a to 492c connection parts 493a to 493c connection parts 495a to 495c common mode choke coils 496a to 496c magnetic cores 497a and 497b magnetic cores 498a to 498c resistors 499a to 499c resistors 500, 500a, and 500b circuits PS DC power supply SW semiconductor switch element (It should be noted that the content of ID=15 was translated as "490 wiring" for the sake of consistency in numbering and following the context. If there is a specific correct translation for this item, it can be adjusted accordingly.)

Claims

1. A predetermined electrode provided for connection to the outside of a wiring board, A pair of rigid substrates provided for each of the plurality of semiconductor elements connected in parallel to the predetermined electrode, At least a portion thereof is a soft substrate provided so as to be sandwiched between all of the pair of hard substrates, A first electrode connecting the control terminal of the semiconductor element to the hard substrate or the soft substrate, A second electrode connecting the reference potential terminal of the semiconductor element to the hard substrate or the soft substrate, The entire wiring is provided on a wiring board so that at least a portion of it is provided on the soft substrate, and the first wiring connects the first electrode of each of the plurality of semiconductor elements in parallel to the third electrode included in the predetermined electrode, The entire circuit board is provided on a wiring board such that at least a portion of it is provided on the soft substrate, and includes a second wiring that connects the second electrode of each of the plurality of semiconductor elements in parallel to the fourth electrode included in the predetermined electrode, Wiring board.

2. A predetermined electrode provided for connection to the outside of a wiring board, A rigid substrate is provided for each of the multiple semiconductor elements connected in parallel to the predetermined electrode, A flexible substrate connecting the rigid substrates, A first electrode connecting the control terminal of the semiconductor element and the hard substrate, A second electrode connecting the reference potential terminal of the semiconductor element and the rigid substrate, A first wiring provided on the rigid substrate and the flexible substrate, which connects the first electrode of each of the plurality of semiconductor elements in parallel to a third electrode included in the predetermined electrode, The rigid substrate and the soft substrate are provided with a second wiring that connects the second electrode of each of the plurality of semiconductor elements in parallel to a fourth electrode included in the predetermined electrode, The aforementioned flexible substrate connects all of the rigid substrates for each of the multiple semiconductor elements. Wiring board.

3. The aforementioned rigid substrate has three or more wiring layers, The first wiring is provided in the inner layer of three or more wiring layers in the rigid substrate. The second wiring is provided on both outer layers of the three or more wiring layers in the rigid substrate, and is also provided in the inner layer so as to sandwich the first wiring between them. A wiring board according to claim 1 or 2.

4. The aforementioned flexible substrate has three or more wiring layers, The first wiring is provided in the inner layer of three or more wiring layers in the flexible substrate. The second wiring is provided on both outer layers of the three or more wiring layers in the flexible substrate, and is also provided in the inner layer so as to sandwich the first wiring between them. A wiring board according to any one of claims 1 to 3.

5. In at least one of the rigid substrate and the flexible substrate, the first wiring and the second wiring are alternately stacked. A wiring board according to any one of claims 1 to 4.

6. The common mode choke coil includes a primary coil provided on the first wiring and a secondary coil provided on the second wiring. A wiring board according to any one of claims 1 to 5.

7. The device comprises a magnetic core for a common-mode choke that surrounds the first and second wirings, A wiring board according to any one of claims 1 to 5.

8. The magnetic core has a notch, and is fixed to the hard substrate by the notch. The wiring board according to claim 7.

9. The first wiring comprises a first resistor, A wiring board according to any one of claims 1 to 5.

10. The second wiring comprises a second resistor, A wiring board according to any one of claims 1 to 5 and 9.

11. The third electrode is connected to a drive circuit that drives the plurality of semiconductor elements, The third electrode has a coaxial structure, A wiring board according to any one of claims 1 to 10.

12. The third electrode and the drive circuit are connected by a coaxial circuit. The wiring board according to claim 11.

13. The third electrode is connected to a drive circuit that drives the plurality of semiconductor elements, Slits are provided in the wiring pattern of the first wiring such that the parasitic impedance is equal between the parallel connection path between the third electrode and the first electrode of each of the plurality of semiconductor elements. A wiring board according to any one of claims 1 to 12.

14. The first electrode, the second electrode, the first wiring, and the second wiring are mounted for each of the multiple semiconductor elements, which constitute one set. A wiring board according to any one of claims 1 to 13.

15. A wiring board according to any one of claims 1 to 14, The plurality of semiconductor elements are provided, Power converter.

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