Circuit structure

Abstract

The circuit structure includes: a first bus bar formed of a coating material; a second bus bar; an insulating member including an insulating portion located between the first and second bus bars; and an electronic component disposed on the first and second bus bars so as to straddle the insulating portion. The electronic component has a connection terminal connected to the first bus bar.

Description

Technical Field

[0001] The present disclosure relates to a circuit structure. Background Art

[0002] Patent Document 1 discloses a heat dissipation substrate on which electronic components are mounted.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 9-321395 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Sometimes, an insulating member is arranged between multiple busbars, and the electronic component is arranged on the multiple busbars in a manner that straddles the insulating member. In addition, sometimes the connection terminal of the electronic component is joined to the busbar. On the other hand, the linear expansion coefficient of the busbar is sometimes different from the linear expansion coefficient of the insulating member such as resin. Therefore, when the busbar and the insulating member change according to the ambient temperature, thermal stress may be generated in the joint between the connection terminal of the electronic component and the busbar, and cracks may be generated in the joint. As a result, the reliability of the joint may be reduced. In the case where the package of the electronic component is a leadless type, this problem becomes more significant.

[0008] Therefore, an object of the present invention is to provide a technology capable of improving the reliability of a joint between a connection terminal of an electronic component and a bus bar.

[0009] Technical solutions to problems

[0010] The circuit structure disclosed herein comprises: a first bus bar formed of a coating material; a second bus bar; an insulating member including an insulating portion located between the first bus bar and the second bus bar; and an electronic component arranged on the first bus bar and the second bus bar in a manner spanning the insulating portion, the electronic component having a connection terminal connected to the first bus bar.

[0011] Effects of the Invention

[0012] According to the present disclosure, the reliability of the joint between the connection terminal of the electronic component and the bus bar can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic perspective view showing an example of a circuit structure.

[0014] Figure 2 It is a schematic plan view showing an example of a circuit structure.

[0015] Figure 3 This is a schematic diagram showing an example of a cross-sectional structure of a circuit structure.

[0016] Figure 4 This is a schematic diagram showing an example of a cross-sectional structure of a circuit structure.

[0017] Figure 5 This is a schematic diagram showing an example of a cross-sectional structure of a circuit structure.

[0018] Figure 6 It is a schematic perspective view showing an example of the structure of a part of a circuit structure.

[0019] Figure 7 It is a schematic plan view showing an example of an electronic component.

[0020] Figure 8 It is a schematic perspective view showing an example of a wiring board.

[0021] Figure 9 It is a schematic perspective view showing an example of the structure of a part of a circuit structure.

[0022] Figure 10 This is a schematic perspective view for explaining an example of a method for manufacturing a circuit structure.

[0023] Figure 11 This is a schematic perspective view for explaining an example of a method for manufacturing a circuit structure.

[0024] Figure 12 This is a schematic perspective view for explaining an example of a method for manufacturing a circuit structure.

[0025] Figure 13 This is a schematic perspective view for explaining an example of a method for manufacturing a circuit structure.

[0026] Figure 14 This is a schematic perspective view for explaining an example of a method for manufacturing a circuit structure.

[0027] Figure 15 This is a schematic perspective view for explaining an example of a method for manufacturing an electric junction box.

[0028] Figure 16 This is a schematic perspective view showing an example of an electric junction box.

[0029] Figure 17 It is a schematic perspective view showing an example of a circuit structure.

[0030] Figure 18 It is a schematic plan view showing an example of a circuit structure.

[0031] Figure 19 This is a schematic diagram showing an example of a cross-sectional structure of a circuit structure.

[0032] Figure 20 This is a schematic diagram showing an example of a cross-sectional structure of a circuit structure.

[0033] Figure 21 This is a schematic diagram showing an example of a cross-sectional structure of a circuit structure.

[0034] Figure 22 It is a schematic perspective view showing an example of the structure of a part of a circuit structure.

[0035] Figure 23 It is a schematic perspective view showing an example of the structure of a part of a circuit structure.

[0036] Figure 24 It is a schematic perspective view showing an example of the structure of a part of a circuit structure.

[0037] Figure 25 This is a schematic perspective view for explaining an example of a method for manufacturing a circuit structure.

[0038] Figure 26 This is a schematic perspective view for explaining an example of a method for manufacturing a circuit structure.

[0039] Figure 27 This is a schematic perspective view showing an example of an electric junction box.

[0040] Figure 28 This is a schematic diagram showing an example of a cross-sectional structure of a circuit structure.

[0041] Figure 29 This is a schematic diagram showing an example of a cross-sectional structure of a circuit structure. DETAILED DESCRIPTION

[0042] [Description of Embodiments of the Present Disclosure]

[0043] First, embodiments of the present disclosure are listed for description.

[0044] The circuit structure of the present disclosure is as follows.

[0045] (1) A circuit structure comprising: a first bus bar formed of a coating material; a second bus bar; an insulating member including an insulating portion located between the first bus bar and the second bus bar; and an electronic component disposed on the first bus bar and the second bus bar so as to straddle the insulating portion, the electronic component having a connection terminal joined to the first bus bar. According to the present disclosure, since the first bus bar is formed of a coating material, a material that is easily joined can be used as the material for the portion of the first bus bar that is joined to the connection terminal of the electronic component. Therefore, the connection terminal of the electronic component can be easily joined to the first bus bar. On the other hand, the linear expansion coefficient of the material that is easily joined and that of the insulating member may differ significantly. Even in this case, by selecting a material having a linear expansion coefficient close to that of the insulating member as the material for the other portions of the first bus bar, the linear expansion coefficient of the entire first bus bar can be made close to that of the insulating member. As a result, the connection terminal can be easily joined to the first bus bar, and thermal stress is less likely to be generated in the joint portion between the connection terminal and the first bus bar. As a result, the reliability of the joint portion is improved.

[0046] (2) Alternatively, the first busbar may include: a first metal layer; and a second metal layer stacked on the first metal layer in the thickness direction of the first busbar, wherein the connection terminal is bonded to the second metal layer. In this case, the first busbar made of a cladding material can be simply manufactured by stacking the first metal layer and the second metal layer. In addition, when a metal layer that is easier to bond to the connection terminal of the electronic component than the first metal layer is used as the second metal layer, the connection terminal of the electronic component can be easily bonded to the second metal layer, and the linear expansion coefficient of the entire first busbar can be made close to the linear expansion coefficient of the insulating member.

[0047] (3) Alternatively, the first metal layer may be an aluminum layer, and the second metal layer may be a copper layer or a copper layer with metal plating applied to the surface. In this case, the first busbar made of the coating material can be simply made using aluminum and copper. In addition, copper is easier to bond to the connection terminals of the electronic component than aluminum. On the other hand, the linear expansion coefficient of aluminum is closer to that of the insulating member than that of copper. Therefore, it is possible to facilitate the bonding of the connection terminals of the electronic component to the second metal layer, and it is possible to make the linear expansion coefficient of the entire first busbar close to that of the insulating member.

[0048] (4) The linear expansion coefficient of the first metal layer may be closer to the linear expansion coefficient of the insulating member than the linear expansion coefficient of the second metal layer. In this case, a metal layer having a linear expansion coefficient close to the linear expansion coefficient of the insulating member can be used as the first metal layer, regardless of the bondability with the connection terminal of the electronic component.

[0049] (5) Alternatively, the upper end surface of the insulating portion may be flush with or located below the upper surface of the first metal layer. In this case, the second metal layer is less susceptible to deformation of the insulating portion caused by changes in ambient temperature. As a result, thermal stress is less likely to be generated at the junction between the second metal layer and the connecting terminal. Therefore, a metal layer having a large difference in linear expansion coefficient with the insulating member can be used as the second metal layer.

[0050] (6) Alternatively, the first bus bar, the second bus bar, and the insulating member may be integrally formed. In this case, a member for integrating the first bus bar, the second bus bar, and the insulating member is not required in the circuit structure. This simplifies the structure of the circuit structure.

[0051] (7) The second bus bar may be formed of a coating material. In this case, the linear expansion coefficient of the entire second bus bar can be made close to the linear expansion coefficient of the insulating member.

[0052] [Details of the embodiments of the present disclosure]

[0053] Specific examples of the circuit structure disclosed herein will be described below with reference to the accompanying drawings. The present invention is not limited to these examples, but is indicated by the scope of the claims and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

[0054] [Implementation Method 1]

[0055] <Outline Description of Circuit Structure>

[0056] Figure 1 1A is a schematic perspective view showing a circuit structure 1A according to this embodiment. The circuit structure 1A is incorporated into, for example, an electrical junction box 900 (see the following). Figure 16 The electrical junction box 900 is provided in a power supply path between a battery and various electrical components in an automobile, for example.

[0057] like Figure 1 As shown, circuit structure 1A includes an input-side bus bar 2 (also simply referred to as bus bar 2), an output-side bus bar 3 (also simply referred to as bus bar 3), and an insulating member 4 for electrically insulating input-side bus bar 2 from output-side bus bar 3. Circuit structure 1A also includes a wiring substrate 5, a plurality of electronic components 6, an electronic component 7, a connector 8, and a plurality of conductive sheets 9.

[0058] Busbars 2 and 3 are conductive components. Each electronic component 6 is, for example, a switching element. Specifically, each electronic component 6 is, for example, a MOSFET (metal-oxide-semiconductor field-effect transistor). MOSFET is a type of semiconductor switching element. Electronic component 7 is, for example, a diode. Specifically, electronic component 7 is, for example, a Zener diode. Hereinafter, electronic component 6 is sometimes referred to as MOSFET 6. In addition, electronic component 7 is sometimes referred to as Zener diode 7. Electronic component 6 may also be a switching element other than MOSFET. In addition, electronic component 6 may also be an electronic component other than a switching element. Electronic component 7 may also be a diode other than a Zener diode. In addition, electronic component 7 may also be an electronic component other than a diode.

[0059] The drain terminals of multiple MOSFETs 6 are, for example, electrically connected to each other. In addition, the source terminals of multiple MOSFETs 6 are, for example, electrically connected to each other. The Zener diode 7 is an electronic component used to prevent an overvoltage from being applied between the drain terminal and the source terminal of the MOSFET 6. The cathode terminal of the Zener diode 7 is, for example, electrically connected to the drain terminals of the multiple MOSFETs 6. The anode terminal of the Zener diode 7 is, for example, electrically connected to the source terminals of the multiple MOSFETs 6. The drain terminal of each MOSFET 6 is electrically connected to the input side bus bar 2. The source terminal of each MOSFET 6 is electrically connected to the output side bus bar 3. Each of the drain terminal, source terminal and gate terminal of the MOSFET 6 can also be referred to as a connection terminal. Similarly, each of the cathode terminal and anode terminal of the Zener diode 7 can also be referred to as a connection terminal. In this example, the circuit structure 1A has four MOSFETs 6, but the number of MOSFETs 6 provided in the circuit structure 1A is not limited to this.

[0060] The busbar 2 is, for example, a plate-shaped metal member. The busbar 2 includes, for example, a main body 20 and an input terminal 21 protruding from the main body 20. The main body 20 and the input terminal 21 are located on the same plane. The main body 20 is, for example, a roughly L-shaped plate-shaped portion. The main body 20 includes a first portion 201 and a second portion 202 forming an L-shape with the first portion 201. Each of the first portion 201 and the second portion 202 is, for example, a rectangular plate-shaped portion. The drain terminal of each MOSFET 6 is electrically connected to the first portion 201. The cathode terminal of the Zener diode 7 is electrically connected to the second portion 202. The input terminal 21 is a plate-shaped portion that protrudes from one end of the second portion 202 in the longitudinal direction. The input terminal 21 has a through hole 210 that extends through the input terminal 21 in the thickness direction. For example, a wiring member extending from a battery is connected to the input terminal 21 using the through hole 210. For example, after passing a bolt through the through-hole of the connection terminal provided in the wiring member and the through-hole 210 of the input terminal portion 21, a nut is attached to the bolt, thereby bolt-fixing the connection terminal of the wiring member to the input terminal portion 21. The output voltage of the battery is applied to the input terminal portion 21 via the wiring member. The output voltage of the battery applied to the input terminal portion 21 is applied to the drain terminal of each MOSFET 6 through the main body portion 20.

[0061] The busbar 3 is, for example, a plate-shaped metal member. The busbars 2 and 3 are located on the same plane. The busbar 3 includes a main body 30 and an output terminal portion 31 protruding from the main body 30. The main body 30 and the output terminal portion 31 are located on the same plane. The main body 30 is, for example, a rectangular plate-shaped portion. A wiring substrate 5 is provided on the main body 30. The main body 30 is located on the same plane as the main body 20 in a manner adjacent to the first portion 201 and the second portion 202 of the main body 20. The long side direction of the main body 30 is parallel to the long side direction of the first portion 201. The source terminal of each MOSFET 6 and the anode terminal of the Zener diode 7 are electrically connected to the main body 30.

[0062] The output terminal portion 31 is a plate-shaped portion that protrudes from one end of the main body portion 30 in the short-side direction. The output terminal portion 31 is located adjacent to the input terminal portion 21 and on the same plane. The output terminal portion 31 has a through-hole 310 extending through the output terminal portion 31 in the thickness direction. For example, a wiring member extending from an electrical component is connected to the output terminal portion 31 using the through-hole 310, similar to the input terminal portion 21. The voltage output from the source terminal of the MOSFET 6 is applied to the output terminal portion 31. The voltage applied to the output terminal portion 31 is applied to the electrical component via the wiring member, for example, as a power supply.

[0063] Insulating member 4 electrically insulates busbars 2 and 3 and holds them together. Insulating member 4 is made of, for example, an insulating resin. Specifically, insulating member 4 is made of, for example, PPS (Poly Phenylene Sulfide Resin). Insulating member 4 is integrally molded with busbars 2 and 3. Insulating member 4 is integrally molded with busbars 2 and 3, for example, by insert molding. Insulating member 4 includes a frame-shaped insulating portion 41 and an L-shaped insulating portion 42 connected to insulating portion 41. Frame-shaped insulating portion 41 is attached to main body portions 20 and 30 so as to surround main body portions 20 and 30. L-shaped insulating portion 42 is located between L-shaped main body portions 20 and 30. Insulating portion 42 is located between first portion 201 of main body portion 20 and main body portion 30, and between second portion 202 of main body portion 20 and main body portion 30. Busbars 2 and 3 are electrically insulated by insulating portion 42.

[0064] The wiring substrate 5 is, for example, a rectangular plate-shaped component. The wiring substrate 5 is provided on the main body 30 of the busbar 3. The wiring substrate 5 includes, for example, an insulating substrate 50 and a conductive layer 51 provided on the insulating substrate 50. The insulating substrate 50 may be, for example, a ceramic substrate or a substrate containing resin. In the latter case, the insulating substrate 50 may be a glass epoxy resin substrate or another substrate containing resin. The thickness of the insulating substrate 50 may be set to, for example, not less than 0.4 mm and not more than 0.6 mm. The conductive layer 51 may be made of copper or other metals. The conductive layer 51 is, for example, provided on the upper surface of the insulating substrate 50. The wiring substrate 5 has the conductive layer 51 on its upper surface. The wiring substrate 5 may be a single-layer substrate or a multi-layer substrate. The wiring substrate 5 may have a conductive layer not only on the upper surface but also on the lower surface and in an inner layer. The gate terminal of each MOSFET 6 is electrically connected to the conductive layer 51 of the wiring substrate 5. In this example, the wiring substrate 5 is a rigid substrate, but may be a sheet-shaped flexible substrate, or may be a composite substrate in which a rigid substrate and a flexible substrate are integrated.

[0065] Connector 8 is provided on the upper surface of wiring board 5. Gate terminals of a plurality of MOSFETs 6 are electrically connected to connector 8 via conductive layer 51 of wiring board 5. Each MOSFET 6 is externally switched via connector 8.

[0066] Multiple conductive sheets 9 are provided corresponding to multiple MOSFETs 6. Each conductive sheet 9 is provided to reduce the resistance between the source terminal of the corresponding MOSFET 6 and the bus bar 3. The conductive sheet 9 can be made of copper, for example, or other metals. In the former case, the conductive sheet 9 can be made of oxygen-free copper, for example. This oxygen-free copper is, for example, oxygen-free copper C1020 specified by the Japanese Industrial Standards (JIS). Alternatively, the conductive sheet 9 can be made of a copper alloy.

[0067] <Detailed description of circuit structure>

[0068] Figure 2 It is a schematic plan view showing the circuit structure 1A. Figure 3 Yes Figure 2 The schematic diagram of the cross-sectional structure as viewed along arrow AA is shown. Figure 4 Yes Figure 2 Schematic diagram of the cross-sectional structure viewed along arrow BB shown. Figure 5 Yes Figure 2 The schematic diagram of the cross-sectional structure when viewed from arrow CC is shown. Figure 6 1A is a schematic perspective view showing an example of the bus bar 2, bus bar 3, insulating member 4 and wiring substrate 5 included in the circuit structure 1A. Figure 6 , the wiring substrate 5 is shown separated from the bus bar 3 .

[0069] <Bus Bar Configuration Example>

[0070] The bus bar 2 is made of, for example, a cladding material. The cladding material is also called a cladding metal. In this example, the bus bar 2 is made of, for example, two layers. Figures 3-5 As shown, busbar 2 includes a metal layer 250 on the lower surface (also referred to as lower metal layer 250) and a metal layer 260 on the upper surface (also referred to as upper metal layer 260). Metal layers 250 and 260 are stacked in the thickness direction of busbar 2. Metal layers 250 and 260 are bonded to each other by, for example, assembly rolling, cast rolling, explosive welding, overlay welding, or diffusion welding. The interface between metal layers 250 and 260 is, for example, diffusion-bonded.

[0071] Busbar 2 is made of, for example, a copper and aluminum cladding material. In this example, lower metal layer 250 is, for example, an aluminum layer, and upper metal layer 260 is, for example, a copper layer. Lower metal layer 250 is made of, for example, pure aluminum. This pure aluminum is, for example, A1050 pure aluminum as specified by JIS. Upper metal layer 260 is made of, for example, oxygen-free copper. This oxygen-free copper is, for example, C1020 oxygen-free copper as specified by JIS.

[0072] The linear expansion coefficient of metal layer 250 is, for example, closer to that of insulating member 4 than that of metal layer 260. In this example, the linear expansion coefficient of insulating member 4, made of PPS, is, for example, 40 ppm / °C. The linear expansion coefficient of metal layer 250, made of pure aluminum, is, for example, 24 ppm / °C. The linear expansion coefficient of metal layer 260, made of oxygen-free copper, is, for example, 17 ppm / °C. The linear expansion coefficient is sometimes referred to as the thermal expansion coefficient. Furthermore, the electrical conductivity of upper metal layer 260 is greater than that of lower metal layer 250.

[0073] Each of the upper and lower surfaces of busbar 2 is, for example, flat. Specifically, each of the upper surface of upper metal layer 260 and the lower surface of lower metal layer 250 is, for example, flat. The thickness of metal layer 250 is, for example, set to be greater than the thickness of metal layer 260. For example, the thickness of metal layer 250 can be set to 3 mm, and the thickness of metal layer 260 can be set to 2 mm.

[0074] The bus bar 3 is made of a coating material, for example, similar to the bus bar 2. In this example, the bus bar 3 is made of two layers, for example. Figures 3-5 As shown, busbar 3 includes a metal layer 350 on the lower surface side (also referred to as lower metal layer 350) and a metal layer 360 on the upper surface side (also referred to as upper metal layer 360). Metal layers 350 and 360 are bonded to each other by, for example, assembly rolling, cast rolling, explosive welding, overlay welding, or diffusion welding. The interface between metal layers 350 and 360 is, for example, diffusion bonded.

[0075] Busbar 3 is composed, for example, of a cladding material of copper and aluminum. In this example, lower metal layer 350 is, for example, an aluminum layer, and upper metal layer 360 is, for example, a copper layer. Lower metal layer 350 is composed, for example, of pure aluminum, such as A1050 aluminum specified in JIS. Upper metal layer 360 is composed, for example, of oxygen-free copper, such as C1020 copper specified in JIS.

[0076] The linear expansion coefficient of metal layer 350 is, for example, closer to that of insulating member 4 than that of metal layer 360. In this example, the linear expansion coefficient of metal layer 350, which is composed of pure aluminum, is, for example, 24 ppm / °C. The linear expansion coefficient of metal layer 360, which is composed of oxygen-free copper, is, for example, 17 ppm / °C. Furthermore, the electrical conductivity of upper metal layer 360 is greater than that of lower metal layer 350.

[0077] The lower surface of the bus bar 3 is, for example, flat. That is, the lower surface of the lower metal layer 350 is, for example, flat. The lower surface of the bus bar 3 is, for example, located on the same plane as the lower surface of the bus bar 2. On the other hand, Figure 6As shown, the upper surface of the bus bar 3 has an area 301 one level lower than other areas. This area 301 serves as a substrate mounting area 301 on which the wiring substrate 5 is mounted. For example, a portion of the upper surface of the main body 30 constitutes the substrate mounting area 301 .

[0078] In this example, the upper surface of upper metal layer 360 is partially lowered, and this lowered area constitutes substrate mounting area 301. That is, substrate mounting area 301 is provided on the upper surface of upper metal layer 360. Substrate mounting area 301 is, for example, lower than the upper surface of bus bar 2. The area of the upper surface of bus bar 3 other than substrate mounting area 301 is, for example, flush with the upper surface of bus bar 2.

[0079] A plurality of conductive protrusions 302 are provided on substrate mounting area 301. Each of protrusions 302 is formed, for example, from a portion of bus bar 3. Specifically, each of protrusions 302 is formed, for example, from a portion of metal layer 360. It can be said that each protrusion 302 is integrally formed with bus bar 3. Alternatively, each protrusion 302 can be said to be integrally formed with metal layer 360. In this example, since protrusion 302 is part of metal layer 360, it is formed, for example, from copper.

[0080] Each protrusion 302 has a disk shape, for example. When the wiring substrate 5 is mounted on the substrate mounting area 301 , the plurality of protrusions 302 are respectively inserted into a plurality of through holes 52 (described later) provided in the wiring substrate 5 .

[0081] The plurality of protrusions 302 include, for example, four protrusions 302a corresponding to four MOSFETs 6, respectively. Furthermore, the plurality of protrusions 302 include two protrusions 302b corresponding to the Zener diodes 7. The plurality of protrusions 302a are arranged along the longitudinal direction of the main body 30. The plurality of protrusions 302a are provided at the ends of the main body 30 in the transverse direction, on the side of the first portion 201 of the bus bar 2. The plurality of protrusions 302a are arranged along the first portion 201 of the bus bar 2. The two protrusions 302b are arranged along the transverse direction of the main body 30. The two protrusions 302b are provided at the ends of the main body 30 in the transverse direction, on the side of the second portion 202 of the bus bar 2. Among the plurality of protrusions 302a, the protrusion 302a closest to the second portion 202 and the two protrusions 302b are arranged along the transverse direction of the main body 30. The functions of the protrusions 302a and 302b will be described in detail later.

[0082] The thickness of metal layer 350 is set to be greater than that of metal layer 360. For example, the thickness of metal layer 350 can be set to 3 mm. In addition, the thickness of the portion of metal layer 360 where the substrate mounting area 301 is not located on the upper surface can be set to 2 mm.

[0083] <Example of MOSFET Structure>

[0084] Figure 7 This is a schematic top view showing an example of the back side of MOSFET6. Here, for ease of explanation, the right and left sides of Figure 7 are respectively regarded as the right and left sides of MOSFET6, and the Figure 7 up-down direction is regarded as the up-down direction of MOSFET6 to explain the structure of MOSFET6.

[0085] MOSFET6 is, for example, a surface mount component. As Figure 7 shown, MOSFET6 includes a package body 60 that houses semiconductor elements and the like. The package body 60 is, for example, a leadless package body. The package body 60 includes a main body portion 65, a gate terminal 61, a plurality of source terminals 62, and a drain terminal 63. The gate terminal 61, the plurality of source terminals 62, and the drain terminal 63 are provided on the back side of the main body portion 65.

[0086] The main body portion 65 is made of, for example, a resin such as epoxy resin. The plurality of source terminals 62 are electrically connected to each other inside the main body portion 65. The gate terminal 61, the source terminals 62, and the drain terminal 63 are made of, for example, metal. The gate terminal 61, the source terminals 62, and the drain terminal 63 can be made of oxygen-free copper, for example. This oxygen-free copper is, for example, oxygen-free copper of C1020 specified by JIS. Additionally, the gate terminal 61, the source terminals 62, and the drain terminal 63 can also be made of a copper alloy. The gate terminal 61, the source terminals 62, and the drain terminal 63 are, for example, in a flat plate shape.

[0087] At the right end portion of the back side of the main body portion 65, the gate terminal 61 and the plurality of source terminals 62 are arranged in a row along the up-down direction. The gate terminal 61 and the plurality of source terminals 62 protrude slightly outward from the right end of the back side of the main body portion 65. The left end of the drain terminal 63 is in a concavo-convex shape, and a plurality of convex portions 63a arranged in the up-down direction are provided at the left end. The plurality of convex portions 63a protrude slightly outward from the left end of the back side of the main body portion 65.

[0088] In addition, the shape of the package body 60 is not limited to the above example. For example, the shape of the drain terminal 63 can also be Figure 7 a shape other than the shape shown. Additionally, the number of source terminals 62 included in the package body 60 can also be a number other than three. Additionally, the package body 60 can also be a leaded package body.

[0089] <Example of Zener Diode Structure>

[0090] Use Figure 2 and Figure 5 to explain the structure of the Zener diode 7. Here, for ease of explanation, take Figure 2The left and right sides of the zener diode 7 are respectively used as the upper and lower sides, and the Figure 2 The structure of the Zener diode 7 will be described with the up-down direction of FIG as the left-right direction of the Zener diode 7 .

[0091] like Figure 2 and Figure 5 As shown, the Zener diode 7 includes a package 70 that houses a semiconductor element, etc. The package 70 is, for example, a lead-type package and includes a main body 75 , a cathode terminal 71 , and anode terminals 72 and 73 .

[0092] The main body 75 is made of, for example, a resin such as epoxy resin. The cathode terminal 71 and the anode terminals 72 and 73 are made of, for example, metal. They can also be made of, for example, oxygen-free copper. For example, this oxygen-free copper uses oxygen-free copper specified in JIS C1020. Furthermore, the cathode terminal 71 and the anode terminals 72 and 73 can also be made of a copper alloy. The cathode terminal 71 is, for example, in the form of a flat plate. The anode terminals 72 and 73 are, for example, lead terminals, each having a shape formed by bending an elongated plate at two locations.

[0093] Cathode terminal 71 is provided on the back surface of main body 75. The upper end of cathode terminal 71 slightly protrudes from the upper end of the back surface of main body 75. Anode terminals 72 and 73 extend outward from the lower end surface of main body 75 and are aligned in the left-right direction. The front ends of anode terminals 72 and 73 are placed on wiring substrate 5.

[0094] In addition, the shape of the package body 70 is not limited to the above example. For example, the shape of at least one of the cathode terminal 71 and the anode terminals 72 and 73 may be Figure 2 and Figure 5 In addition, the package 70 may be a leadless package.

[0095] <Structural Example of Wiring Board>

[0096] Figure 8 1 is a schematic perspective view showing an example of a wiring substrate 5. Figure 6 and Figure 8As shown in FIG. 1 , the wiring substrate 5 includes a plurality of through-holes 52 extending through the wiring substrate 5 in the thickness direction. For example, the plurality of through-holes 52 include four through-holes 52a corresponding to four MOSFETs 6, and two through-holes 52b corresponding to Zener diodes 7. The four through-holes 52a are arranged along the longitudinal direction of the wiring substrate 5 at one end portion thereof in the lateral direction. The two through-holes 52b are arranged along the lateral direction of the wiring substrate 5 at one end portion thereof in the lateral direction. The through-hole 52a closest to the end portion of the plurality of through-holes 52a and the two through-holes 52b are arranged along the lateral direction of the wiring substrate 5. The MOSFETs 6 corresponding to the through-holes 52a are arranged near the through-holes 52a. The Zener diodes 7 are arranged near the two through-holes 52b.

[0097] like Figure 6 and Figure 8 As shown in FIG. 1 , the conductive layer 51 of the wiring substrate 5 includes a plurality of conductive regions 53 corresponding to the plurality of MOSFETs 6. In addition, the conductive layer 51 includes a conductive region 54 corresponding to the connector 8 and a wiring region 55. Figures 3-5 In the figure, the conductive layer 51 is omitted.

[0098] The conductive region 53 has a land 531 to which the gate terminal 61 of the corresponding MOSFET 6 is bonded. The conductive region 53 has three lands 532 to which the three source terminals 62 of the corresponding MOSFET 6 are bonded. The lands to which terminals are bonded are also called pads.

[0099] Each conductive region 53 includes an extension region 533 extending from the plurality of lands 532. The extension region 533 included in the conductive region 53 corresponding to the MOSFET 6 is located around the through-hole 52a corresponding to the MOSFET 6. The extension region 533 is provided so as to surround the opening edge of the through-hole 52a (specifically, the opening edge on the upper surface side of the wiring substrate 5). It can also be said that the through-hole 52a is provided in the extension region 533. Each land 532 can also be said to be a protrusion protruding from the extension region 533.

[0100] In this example, the through hole 52a is, for example, a through hole having a conductive region formed on its inner circumference. On the other hand, the through hole 52b is, for example, not a through hole and has no conductive region formed on its inner circumference. The conductive region on the inner circumference of the through hole 52a is, for example, made of metal. The conductive region on the inner circumference of the through hole 52a may be made of the same material as the conductive layer 51 or a different material. The conductive region on the inner circumference of the through hole 52a is connected to the extended region 533 surrounding the through hole 52a. In addition, the conductive region may not be formed on the inner circumference of the through hole 52a. In addition, the through hole 52b may also be a through hole having a conductive region formed on its inner circumference.

[0101] The conductive area 54 corresponding to the connector 8 includes, for example, four connection pads 541 and two connection pads 542. The two connection pads 542 are used to fix the connector 8 to the wiring substrate 5. Two metal areas for fixing are provided on the back of the connector 8. The two metal areas are respectively joined to the two connection pads 542 by, for example, solder. Solder is mainly composed of tin. In addition, the connector 8 has four connection terminals 81 (see FIG. 1 ) which are respectively electrically connected to the gate terminals 61 of the plurality of MOSFETs 6. Figure 2 Each connection terminal 81 is made of metal, for example. The plurality of connection terminals 81 of the connector 8 are respectively joined to the plurality of connection lands 541 by, for example, soldering.

[0102] The wiring region 55 includes, for example, four wirings 551 electrically connected to the gate terminals 61 of the four MOSFETs 6. One end of each of the wirings 551 is connected to a plurality of lands 531 to which the gate terminals 61 of the MOSFETs 6 are bonded. The other ends of each of the wirings 551 are connected to a plurality of lands 541 to which the connection terminals 81 of the connector 8 are bonded. The gate terminals 61 are electrically connected to the connection terminals 81 of the connector 8 via the wirings 551.

[0103] Wiring substrate 5 having the above-described structure is placed on substrate placement region 301 on the upper surface of bus bar 3. The outer shape of substrate placement region 301 is substantially the same as the outer shape of wiring substrate 5. Figure 9 This is a diagram showing an example of a state in which the wiring substrate 5 is placed on the substrate placement region 301 of the bus bar 3 .

[0104] When wiring substrate 5 is placed on substrate mounting area 301, multiple protrusions 302a of busbar 3 are inserted into multiple through-holes 52a of wiring substrate 5, and multiple protrusions 302b of busbar 3 are inserted into multiple through-holes 52b of wiring substrate 5. When wiring substrate 5 is placed on substrate mounting area 301, protrusions 302a protrude from busbar 3 into through-holes 52a, and protrusions 302b protrude from busbar 3 into through-holes 52b. The diameter of protrusions 302 is set slightly smaller than the diameter of through-holes 52. In other words, protrusions 302 fit into through-holes 52.

[0105] The wiring board 5 on the board placement area 301 is located not only on the bus bar 3 but also on the L-shaped insulating portion 42 between the bus bar 2 and the bus bar 3. Figure 4 and Figure 5 As shown, the peripheral portion 42a (see FIG. 1 ) of the insulating portion 42 located around the substrate mounting region 301 is Figure 6) is flush with the upper surfaces of the lower metal layers 250 and 350, for example. The peripheral portion 42a is not located between the upper metal layer 260 and the upper metal layer 360. The wiring substrate 5 is located on the substrate mounting area 301 and is located above the peripheral portion 42a with a gap from the upper end surface of the peripheral portion 42a located around the substrate mounting area 301. An insulating member such as a tape may be provided in the gap. The wiring substrate 5 is adjacent to the first portion 201 and the second portion 202 of the bus bar 2, respectively. The upper surface of the insulating substrate 50 of the wiring substrate 5 mounted on the substrate mounting area 301 is flush with the upper surface of the bus bar 2 and the upper surface of the bus bar 3 outside the substrate mounting area 301. In addition, the upper surface of the conductive layer 51 on the insulating substrate 50 may also be located on the same plane as the upper surface of the bus bar 2 and the upper surface of the bus bar 3 outside the substrate mounting area 301.

[0106] The wiring substrate 5 is fixed to the substrate mounting area 301 by, for example, a bonding material. As the bonding material, for example, double-sided tape is used. As the bonding material, other components may also be used. In addition, the wiring substrate 5 may also be simply placed in the substrate mounting area 301 without being fixed.

[0107] The upper surface of the protrusion 302 within the through-hole 52 is, for example, flush with the upper surface of the conductive layer 51 on the insulating substrate 50 of the wiring board 5. In this case, the upper surface of the protrusion 302a within the through-hole 52a is flush with the upper surface of the extended region 533 surrounding the through-hole 52a. Alternatively, the upper surface of the protrusion 302 may be flush with the upper surface of the insulating substrate 50.

[0108] <About Conductive Sheet>

[0109] The plurality of conductive sheets 9 are bonded to the plurality of protrusions 302a exposed from the upper surface of the wiring substrate 5. Furthermore, the plurality of conductive sheets 9 are bonded to the plurality of extended regions 533 of the wiring substrate 5. The conductive sheet 9 is provided on the wiring substrate 5 so as to cover the upper surface of the protrusions 302a within the through-hole 52a of the wiring substrate 5 and the peripheral edge of the through-hole 52a. The conductive sheet 9 covers the opening edge of the through-hole 52a (specifically, the opening edge on the upper surface side of the wiring substrate 5). The thickness of the conductive sheet 9 can be set to, for example, not less than 0.2 mm and not more than 0.5 mm.

[0110] The conductive sheet 9 is bonded to the upper surface of the protrusion 302a in the through hole 52a and the extended region 533 around the through hole 52a by the conductive bonding material 115 (see Figure 4Solder, for example, is used as the conductive bonding material 115. The conductive bonding material 115 bonds the back surface of the conductive sheet 9 to the protrusion 302a and the upper surface of the extended region 533, and also bonds the end surface of the conductive sheet 9 to the upper surface of the extended region 533. The conductive bonding material 115 includes a portion located between the protrusion 302a, the extended region 533, and the conductive sheet 9.

[0111] Alternatively, the conductive bonding material 115 may enter the through-hole 52 a . In this case, the conductive region on the inner peripheral surface of the through-hole 52 a serving as a through hole and the protrusion 302 a in the through-hole 52 a may be bonded together by the conductive bonding material 115 .

[0112] <Example of Electronic Component Installation>

[0113] Each MOSFET 6 is mounted across both the bus bar 2 and the wiring substrate 5 on the bus bar 3. For example, the MOSFET 6 is mounted across the first portion 201 of the bus bar 2 and the end portion of the wiring substrate 5 in the short side direction where the conductive region 53 is formed. In other words, the MOSFET 6 is mounted across the first portion 201 of the bus bar 2 and the portion of the wiring substrate 5 adjacent to the first portion 201. Figure 6 As shown, the insulating portion 42 (specifically, the peripheral portion 42a) is located between the first portion 201 of the bus bar 2 and the bus bar 3. The MOSFET 6 is provided on the bus bars 2 and 3 so as to straddle the insulating portion 42.

[0114] The drain terminal 63 of the MOSFET 6 is connected to the upper surface of the first portion 201 of the bus bar 2 via the conductive bonding material 103 (see Figures 2-4 ) and joined. Solder is used as the conductive bonding material 103, for example. The conductive bonding material 103 bonds the back surface and end surface of the drain terminal 63 to the first portion 201. The conductive bonding material 103 includes a portion located between the drain terminal 63 and the first portion 201. The voltage applied to the input terminal portion 21 of the bus bar 2 is applied to the drain terminal 63 bonded to the bus bar 2.

[0115] The gate terminal 61 of the MOSFET 6 is connected to the land 531 of the conductive region 53 corresponding to the MOSFET 6 via the conductive bonding material 101 (see Figure 3) and joined. Solder is used as the conductive bonding material 101, for example. The conductive bonding material 101 bonds the back surface and end surface of the gate terminal 61 to the connection pad 531, for example. The conductive bonding material 101 includes a portion located between the gate terminal 61 and the connection pad 531. The gate terminal 61 is electrically connected to the connection terminal 81 of the connector 8 via the connection pad 531, a wiring 551 connected to the connection pad 531, and a connection pad 541 connected to the wiring 551. Each MOSFET 6 is externally switched on and off via the connector 8.

[0116] The plurality of source terminals 62 of the MOSFET 6 are connected to the plurality of lands 532 of the conductive region 53 corresponding to the MOSFET 6 through the conductive bonding material 102 (see Figure 4 ) and joined. As the conductive bonding material 102, solder is used, for example. The conductive bonding material 102, for example, joins the back surface and end surface of the source terminal 62 to the connecting pad 532. The conductive bonding material 102 includes a portion located between the source terminal 62 and the connecting pad 532. The source terminal 62 is electrically connected to the output side bus bar 3 through the connecting pad 532, the extended area 533 connected to the connecting pad 532, the conductive sheet 9 joined to the extended area 533, and the conductive protrusion 302a joined to the conductive sheet 9. The conductive sheet 9 functions as a relay terminal that electrically connects the source terminal 62 to the protrusion 302a. The output voltage of the source terminal 62 is output to the outside from the output terminal portion 31 of the bus bar 3.

[0117] Similar to MOSFET 6, Zener diode 7 is mounted across busbar 2 and wiring substrate 5 on busbar 3. For example, Zener diode 7 is mounted across second portion 202 of busbar 2 and the longitudinal end of wiring substrate 5 where through-hole 52b is formed. In other words, Zener diode 7 is mounted across second portion 202 of busbar 2 and the portion of wiring substrate 5 adjacent to second portion 202. Insulating portion 42 (specifically, peripheral portion 42a) is located between second portion 202 of busbar 2 and busbar 3. Zener diode 7 is mounted on busbars 2 and 3, straddling insulating portion 42.

[0118] The cathode terminal 71 of the Zener diode 7 is connected to the upper surface of the second portion 202 of the bus bar 2 via the conductive bonding material 111 (see Figure 5 ) are joined. Solder is used as the conductive bonding material 111, for example. The conductive bonding material 111 bonds the back surface and end surface of the cathode terminal 71 to the second portion 202. The conductive bonding material 111 includes a portion located between the cathode terminal 71 and the second portion 202. The cathode terminal 71 is electrically connected to the drain terminal 63 of the MOSFET 6 via the bus bar 2.

[0119] Anode terminal 72 of Zener diode 7 is bonded to one protrusion 302b within one through-hole 52b of wiring substrate 5. Anode terminal 73 of Zener diode 7 is bonded to another protrusion 302b within another through-hole 52b of wiring substrate 5. In this example, protrusion 302b is formed from a portion of bus bar 3, so it can be said that anode terminals 72 and 73 are bonded to the upper surface of bus bar 3.

[0120] Anode terminal 72 is bonded to the upper surface of one protrusion 302b via a conductive bonding material. Solder is used, for example, as the conductive bonding material. The conductive bonding material electrically bonds the back surface and end surface of the front end portion of anode terminal 72 to one protrusion 302b. The conductive bonding material includes a portion located between the front end portion of anode terminal 72 and one protrusion 302b. Anode terminal 72 is electrically connected to source terminal 62 of MOSFET 6 via one protrusion 302b and bus bar 3.

[0121] The anode terminal 73 is connected to the upper surface of the other protrusion 302b via the conductive bonding material 112 (see Figure 5 ) and joined. Solder, for example, is used as conductive bonding material 112. Conductive bonding material 112 bonds the back surface and end surface of the front end portion of anode terminal 73 to the other protrusion 302b. Conductive bonding material 112 includes a portion located between the front end portion of anode terminal 73 and the other protrusion 302b.

[0122] <An Example of a Method for Manufacturing a Circuit Structure>

[0123] When manufacturing the circuit structure 1A having the above structure, first, two cladding materials 10 for making the bus bars 2 and 3 are prepared. Figure 10 As shown, cladding material 10 includes metal layers 10a and 10b stacked together. Metal layer 10a is, for example, an aluminum layer, and metal layer 10b is, for example, a copper layer. Cladding material 10 is produced by diffusion bonding the aluminum and copper plates, for example, by rolling and heat treatment. Metal layer 10a becomes metal layer 250 of busbar 2 or metal layer 350 of busbar 3. Metal layer 10b becomes metal layer 260 of busbar 2 or metal layer 360 of busbar 3.

[0124] Next, one of the two prepared cladding materials 10 is formed into a predetermined shape by, for example, cold forging or cutting. Then, a through hole 210 is provided in the formed cladding member 10. In this way, the bus bar 2 is completed.

[0125] In addition, the other cladding material 10 is formed into a predetermined shape by cold forging or cutting. Then, a through hole 310 is provided in the formed other cladding material 10. Then, a plurality of protrusions 302 are provided on the surface of the other cladding material 10. Thus, the Figure 11 The busbar 3 is shown.

[0126] Then, if Figure 12 As shown in FIG, bus bars 2 and 3 are arranged in the insert molding die. Figure 12 The insert molding die is omitted in the figure. Then, a thermoplastic resin with excellent heat resistance such as PPS is injected from an injection molding machine into the insert molding die, so that the bus bars 2 and 3 are integrally molded with the resin. Figure 13 As shown, an integrally molded product in which the bus bars 2 and 3 and the insulating member 4 are integrally molded is obtained.

[0127] Next, the wiring board 5 is fixed to the board mounting area 301 of the bus bar 3 of the manufactured integrally molded product using a bonding material such as a double-sided tape. Figure 9 The structure shown.

[0128] Then, if Figure 14 As shown in FIG, solder paste 11 is applied to predetermined areas of the upper surfaces of busbars 2, 3, and wiring substrate 5. Figure 14 In the figure, the solder paste 11 is indicated by oblique lines. Then, the plurality of MOSFETs 6, Zener diodes 7, connectors 8 and a plurality of conductive sheets 9 are soldered to the area coated with the solder paste 11 by reflow soldering. Thus, the above-mentioned Figure 1 and Figure 2 The circuit structure 1A shown in FIG.

[0129] Then, if Figure 15 As shown, a control substrate 910 for controlling each MOSFET 6 is mounted on circuit structure 1A. Control substrate 910 includes, for example, a microcomputer and connectors 911 and 912. Connector 912 is connected to connector 8 of circuit structure 1A. Control substrate 910 is electrically connected to gate terminal 61 of each MOSFET 6 via connector 912 and connector 8 connected to connector 912. This enables control substrate 910 to perform switching control on each MOSFET 6. Wiring members extending from an external device are connected to connector 911. Control substrate 910 performs switching control on each MOSFET 6 in response to instructions from the external device.

[0130] Then, if Figure 16As shown, heat sink 920 is attached to the back surfaces of busbars 2 and 3 via a heat conducting member such as a heat sink. Heat generated by circuit structure 1A is thereby dissipated to the outside through heat sink 920. Then, housing 930, which covers wiring board 5, multiple MOSFETs 6, Zener diode 7, connector 8, and multiple conductive sheets 9, is attached to busbars 2 and 3. This completes electrical junction box 900.

[0131] As described above, in this example, the bus bar 2 is made of the cladding material. This makes it easy to connect the drain terminal 63 of the MOSFET 6 to the bus bar 2 , and allows the overall linear expansion coefficient of the bus bar 2 to be close to that of the insulating member 4 .

[0132] For example, as in the example above, consider a case where upper metal layer 260 is composed of a copper layer and lower metal layer 250 is composed of an aluminum layer. In this case, since the portion bonded to drain terminal 63 is composed of copper, which is easily soldered, it is easy to bond drain terminal 63 to bus bar 2. Furthermore, since lower metal layer 250 is composed of an aluminum layer having a linear expansion coefficient relatively close to that of insulating member 4, the linear expansion coefficient of the entire bus bar 2 can be made close to that of insulating member 4.

[0133] In contrast, consider the case where busbar 2 is composed solely of copper (e.g., oxygen-free copper), unlike this example. In this case, while drain terminal 63 can be easily soldered to busbar 2, the linear expansion coefficient of busbar 2 (e.g., 17 ppm / °C) differs significantly from the linear expansion coefficient of insulating member 4 (e.g., 40 ppm / °C). MOSFET 6 is positioned on busbars 2 and 3, straddling insulating portion 42 of insulating member 4. Therefore, if the linear expansion coefficients of busbar 2 and insulating member 4 differ, thermal stress may be generated at the junction between drain terminal 63 and busbar 2 due to changes in ambient temperature. This could lead to cracks in this junction, reducing the reliability of the junction.

[0134] Furthermore, consider the case where busbar 2 is made only of aluminum (e.g., pure aluminum). In this case, the linear expansion coefficient of busbar 2 (e.g., 24 ppm / °C) is closer to that of insulating member 4 than when busbar 2 is made only of copper. Therefore, thermal stress is less likely to be generated in the joint between drain terminal 63 and busbar 2 than when busbar 2 is made only of copper. However, since it is difficult to weld drain terminal 63 to busbar 2 made of aluminum, it is difficult to join drain terminal 63 to busbar 2. As a result, drain terminal 63 and busbar 2 cannot be properly joined, and the reliability of the joint between drain terminal 63 and busbar 2 may be reduced.

[0135] In this example, since busbar 2 is made of a cladding material, as in the example above, a readily bondable material can be used for the portion of busbar 2 that joins drain terminal 63 of MOSFET 6. This makes it easy to join drain terminal 63 to busbar 2. On the other hand, the linear expansion coefficient of the readily bondable material may differ significantly from that of insulating member 4. Even in this case, by selecting a material with a linear expansion coefficient close to that of insulating member 4 for the rest of busbar 2, the overall linear expansion coefficient of busbar 2 can be brought close to that of insulating member 4. This makes it easier to join drain terminal 63 to busbar 2, and thermal stress is less likely to be generated at the joint between drain terminal 63 and busbar 2. As a result, the reliability of this joint is improved. Furthermore, since heat generated by MOSFET 6 can be directly transferred to busbar 2, localized temperature increases are less likely to occur. Similarly, joining cathode terminal 71 to busbar 2 is easier, and thermal stress is less likely to be generated at the joint between cathode terminal 71 and busbar 2. As a result, the reliability of the joint portion is improved.

[0136] Furthermore, in this example, since bus bar 3 is formed of a cladding material, it is easy to join anode terminals 72 and 73 of Zener diode 7 to bus bar 3 (specifically, protrusion 302 b ), and the linear expansion coefficient of bus bar 3 as a whole can be made close to the linear expansion coefficient of insulating member 4 . This facilitates joining anode terminals 72 and 73 to bus bar 3, and thermal stress is less likely to be generated at the joints between anode terminals 72 and 73 and bus bar 3. Consequently, the reliability of these joints is improved.

[0137] In this example, bus bar 2 includes a metal layer 250 and a metal layer 260 laminated on metal layer 250. Therefore, by laminating metal layers 250 and 260, bus bar 2 can be easily manufactured from a cladding material. Furthermore, when metal layer 260 is a metal layer that is more easily bonded to drain terminal 63 and cathode terminal 71 than metal layer 250, bonding of drain terminal 63 and cathode terminal 71 to metal layer 260 is facilitated, and the overall linear expansion coefficient of bus bar 2 can be brought closer to that of insulating member 4. Similarly, bus bar 3 can be easily manufactured from a cladding material by laminating metal layers 350 and 360. Furthermore, when metal layer 360 is a metal layer that is more easily bonded to anode terminals 72 and 73 than metal layer 350, bonding of anode terminals 72 and 73 to metal layer 360 is facilitated, and the overall linear expansion coefficient of bus bar 3 can be brought closer to that of insulating member 4.

[0138] Furthermore, in the busbar 2 of this example, the metal layer 250 is an aluminum layer, and the metal layer 260 is a copper layer. This allows the busbar 2 to be easily fabricated from a cladding material using aluminum and copper. Furthermore, copper is easier to bond to the drain terminal 63 and cathode terminal 71 than aluminum, and aluminum has a linear expansion coefficient closer to that of the insulating member 4 than copper. Therefore, the drain terminal 63 and cathode terminal 71 can be easily bonded to the metal layer 260, and the overall linear expansion coefficient of the busbar 2 can be brought closer to that of the insulating member 4. Similarly, the busbar 3 can be easily fabricated from a cladding material using aluminum and copper. Furthermore, copper is easier to bond to the anode terminals 72 and 73 than aluminum, and aluminum has a linear expansion coefficient closer to that of the insulating member 4 than copper. Therefore, the anode terminals 72 and 73 can be easily bonded to the metal layer 360, and the overall linear expansion coefficient of the busbar 3 can be brought closer to that of the insulating member 4.

[0139] Furthermore, in this example, since the linear expansion coefficient of metal layer 250 is closer to that of insulating member 4 than that of metal layer 260, a metal layer having a linear expansion coefficient close to that of insulating member 4 can be used as metal layer 250, regardless of the bonding between the metal layer 250 and the drain terminal 63 and the cathode terminal 71. Similarly, since the linear expansion coefficient of metal layer 350 is closer to that of insulating member 4 than that of metal layer 360, a metal layer having a linear expansion coefficient close to that of insulating member 4 can be used as metal layer 350, regardless of the bonding between the metal layer 350 and the anode terminals 72 and 73.

[0140] In addition, in this example, the upper end surface of the insulating portion 42 of the insulating member 4 is flush with the upper surface of the lower metal layer 250 having a linear expansion coefficient close to that of the insulating member 4 (for example, see Figure 4 ). As a result, upper metal layer 260 is less susceptible to deformation of insulating portion 42 caused by changes in ambient temperature. As a result, thermal stress is less likely to occur at the junction between upper metal layer 260 and drain terminal 63 and cathode terminal 71. Therefore, a metal layer having a large difference in linear expansion coefficient from insulating member 4 can be used as metal layer 260.

[0141] In addition, in this example, the upper end surface of the insulating portion 42 is flush with the upper surface of the lower metal layer 350 having a linear expansion coefficient close to that of the insulating member 4 (for example, see Figure 5). As a result, upper metal layer 360 is less susceptible to deformation of insulating portion 42 caused by changes in ambient temperature. As a result, thermal stress is less likely to occur in the joints between upper metal layer 360 and anode terminals 72 and 73. Therefore, a metal layer having a large difference in linear expansion coefficient with insulating member 4 can be used as metal layer 360.

[0142] In this example, the upper end surface of the insulating portion 42 is flush with the upper surfaces of the lower metal layer 250 and the lower metal layer 350. The lower metal layer 250 and the lower metal layer 350 are made of the same type of metal, for example, aluminum. Therefore, in the direction ( Figures 3 to 5 The distribution of thermal stress (in the left and right directions) is symmetrical, and the thermal stresses generated in the two cancel each other out. As a result, the junction between the upper metal layer 260 and the drain terminal 63 and the cathode terminal 71 (for example, see Figure 3 、 Figure 5 ) is less likely to generate thermal stress, and the reliability of each joint portion is improved. Similarly, the joint portion between the wiring substrate 5 and the gate terminal 61 and the source terminal 62 on the upper metal layer 360 (for example, see Figure 3 、 Figure 4 ) is less likely to generate thermal stress, and the reliability of each joint portion is improved. Similarly, the joint portion between the upper metal layer 360 and the anode terminals 72 and 73 (for example, see Figure 5 ) is less likely to generate thermal stress, and the reliability of each joining part is improved.

[0143] Furthermore, as in this example, by making the thickness of lower metal layer 250, which has a linear expansion coefficient close to that of insulating member 4, greater than the thickness of upper metal layer 260, the linear expansion coefficient of bus bar 2 as a whole can be made closer to that of insulating member 4. As a result, thermal stress is less likely to be generated in the joint between drain terminal 63 and bus bar 2, further improving the reliability of this joint. Similarly, by making the thickness of lower metal layer 350 greater than that of upper metal layer 360, the linear expansion coefficient of bus bar 3 as a whole can be made closer to that of insulating member 4. As a result, the reliability of the joint between anode terminals 72 and 73 and bus bar 3 is further improved.

[0144] In this example, since the busbars 2 and 3 and the insulating member 4 are integrally formed, no member is required for integrating the busbars 2 and 3 and the insulating member 4. This simplifies the structure of the circuit structure 1A.

[0145] In this example, conductive protrusion 302a protrudes from busbar 3 into through-hole 52a of wiring substrate 5. Therefore, source terminal 62 on wiring substrate 5 can be easily electrically connected to busbar 3 by electrically connecting protrusion 302a in through-hole 52a.

[0146] In this example, conductive protrusion 302b protrudes from busbar 3 into through-hole 52b of wiring substrate 5. Therefore, by electrically connecting anode terminals 72 and 73 on wiring substrate 5 to protrusion 302b in through-hole 52b, anode terminals 72 and 73 can be easily electrically connected to busbar 3.

[0147] In this example, the protrusion 302 is formed by a portion of the bus bar 3 , thereby reducing the resistance between the source terminal 62 and the bus bar 3 , and reducing the resistance between the anode terminals 72 and 73 and the bus bar 3 .

[0148] In addition, in this example, Figure 2 and Figure 5 As shown in FIG. 1 and FIG. 2 , the anode terminals 72 and 73 are engaged with the protrusion 302 b , and thus the electrical resistance between the anode terminals 72 and 73 and the bus bar 3 can be reduced.

[0149] In this example, a conductive sheet 9 is provided. This conductive sheet 9 is bonded to an extended region 533 extending from a land 532 to which the source terminal 62 is bonded and located around the through-hole 52a, and to the upper surface of the protrusion 302a within the through-hole 52a. This conductive sheet 9 reduces the resistance between the source terminal 62 and the bus bar 3. Furthermore, heat generated by the MOSFET 6 is easily transferred to the bus bar 3 via the conductive sheet 9, thereby reducing the risk of localized temperature increases.

[0150] Furthermore, in this example, the extended region 533 surrounds the periphery of the through-hole 52a, and the conductive sheet 9 covers the opening edge of the through-hole 52a. This increases the bonding area between the extended region 533 and the protrusion 302a and the conductive sheet 9. Consequently, the resistance between the source terminal 62 and the bus bar 3 can be further reduced.

[0151] Furthermore, in this example, wiring substrate 5 is positioned on substrate mounting area 301, which is lower than the upper surface of bus bar 2, on the upper surface of bus bar 3. This reduces the height difference between wiring substrate 5 and bus bar 2. Consequently, MOSFET 6 and Zener diode 7 can be easily positioned across wiring substrate 5 and bus bar 2.

[0152] In this example, the gate terminal 61 and the source terminal 62 of the MOSFET 6 are insulated on the wiring substrate 5. Therefore, even if the distance between the gate terminal 61 and the source terminal 62 is reduced, the gate terminal 61 and the source terminal 62 can be properly insulated. Therefore, as the package 60, a narrow-pitch package with a narrow terminal distance can be used.

[0153] In addition, the linear expansion coefficient of the wiring substrate 5 may be closer to the linear expansion coefficient of the insulating member 4 (for example, 40 ppm / °C) than the linear expansion coefficient of the upper metal layers 260 and 360 (for example, 17 ppm / °C). For example, the linear expansion coefficient of the wiring substrate 5 may be 18 ppm / °C or more. In addition, the linear expansion coefficient of the wiring substrate 5 may be closer to the linear expansion coefficient of the insulating member 4 (for example, 40 ppm / °C) than the linear expansion coefficient of the lower metal layers 250 and 350 (for example, 24 ppm / °C). For example, the linear expansion coefficient of the wiring substrate 5 may be 25 ppm / °C or more. As a result, thermal stress is less likely to be generated in the joint portion between the wiring substrate 5 and the gate terminal 61 and the source terminal 62. As a result, the reliability of the joint portion is improved.

[0154] Furthermore, when connecting the connection terminals of the wiring member extending from the battery to the input terminal portion 21 of the busbar 2, the connection terminals of the wiring member may be brought into contact with the upper metal layer 260. The conductivity of the upper metal layer 260 is greater than that of the lower metal layer 250. By bringing the connection terminals of the wiring member into contact with the upper metal layer 260, the resistance between the input terminal portion 21 and the battery can be reduced.

[0155] Furthermore, when connecting the connecting terminals of the wiring member extending from the electrical component to the output terminal portion 31 of the busbar 3, the connecting terminals of the wiring member may be brought into contact with the upper metal layer 360. The electrical conductivity of the upper metal layer 360 is greater than that of the lower metal layer 350. By bringing the connecting terminals of the wiring member into contact with the upper metal layer 360, the electrical resistance between the output terminal portion 31 and the electrical component can be reduced.

[0156] [Implementation Method 2]

[0157] Figure 17 It is a schematic perspective view showing an example of a circuit structure 1B according to the present embodiment. Figure 18 It is a schematic plan view showing an example of the circuit structure 1B. Figure 19 Yes Figure 18 A schematic diagram of an example of a cross-sectional structure viewed in the direction DD. Figure 20 Yes Figure 18 A schematic diagram of an example of a cross-sectional structure viewed in the direction EE. Figure 21 Yes Figure 18A schematic diagram of an example of a cross-sectional structure viewed in the direction FF. Figure 22 This is a schematic perspective view showing an example of the input bus bar 12, output bus bar 13, and relay bus bar 16 included in the circuit structure 1B. The structure of the circuit structure 1B will be described below, focusing on the differences from the circuit structure 1A described above.

[0158] <Outline Description of Circuit Structure>

[0159] The circuit structure 1B includes an input-side bus bar 12 (also simply referred to as bus bar 12), an output-side bus bar 13 (also simply referred to as bus bar 13), a relay bus bar 16 (also simply referred to as bus bar 16), and a wiring substrate 15. Bus bars 12, 13, and 16 are conductive components. The circuit structure 1B also includes the aforementioned MOSFET 6, Zener diode 7, connector 8, and conductive sheet 9. In this example, the circuit structure 1B includes, for example, eight MOSFETs 6, two Zener diodes 7, two connectors 8, and four conductive sheets 9. The number of MOSFETs 6, Zener diodes 7, connectors 8, and conductive sheets 9 included in the circuit structure 1B is not limited to this.

[0160] Drain terminals 63 of four of the eight MOSFETs 6 and cathode terminal 71 of one of the two Zener diodes 7 are electrically connected to input-side bus bar 12. Thus, drain terminals 63 of the four MOSFETs 6 and cathode terminal 71 of the one Zener diode 7 are electrically connected to each other.

[0161] The drain terminals 63 of the remaining four of the eight MOSFETs 6 and the cathode terminal 71 of the other of the two Zener diodes 7 are electrically connected to the output-side bus bar 13. Thus, the drain terminals 63 of the remaining four MOSFETs 6 and the cathode terminal 71 of the other Zener diode 7 are electrically connected to each other.

[0162] The source terminals 62 of the eight MOSFETs 6 and the anode terminals 72 and 73 of the two Zener diodes 7 are electrically connected to the relay bus bar 16. Thus, the source terminals 62 of the eight MOSFETs 6 and the anode terminals 72 and 73 of the two Zener diodes 7 are electrically connected to each other.

[0163] Hereinafter, MOSFET 6 having drain terminal 63 electrically connected to bus bar 12 may be referred to as MOSFET 6a. In addition, MOSFET 6 having drain terminal 63 electrically connected to bus bar 13 may be referred to as MOSFET 6b. Furthermore, Zener diode 7 having cathode terminal 71 electrically connected to bus bar 12 may be referred to as Zener diode 7a. Furthermore, Zener diode 7 having cathode terminal 71 electrically connected to bus bar 13 may be referred to as Zener diode 7b.

[0164] The input-side busbar 12 is a busbar formed by modifying the shape of the busbar 2 of the circuit structure 1A. Busbar 12 is, for example, a plate-shaped metal member that is elongated in one direction. The upper and lower surfaces of busbar 12 are, for example, flat. Busbar 12 includes, for example, a main body 120 and an input terminal portion 121. Main body 120 is, for example, a rectangular plate-shaped portion. The drain terminal 63 of MOSFET 6a and the cathode terminal 71 of Zener diode 7a are electrically connected to main body 120. Input terminal portion 121 protrudes from one end of the main body 120 in the longitudinal direction. Input terminal portion 121 has a through-hole 1210 extending through its thickness. Wiring members extending from a battery, for example, are connected to input terminal portion 121 via through-hole 1210. The battery output voltage is applied to input terminal portion 121 via the wiring member. The battery output voltage applied to input terminal portion 121 is applied to the drain terminals of each MOSFET 6a via main body 120.

[0165] The output-side busbar 13 is a busbar formed by modifying the shape of busbar 3 of circuit structure 1A. Like busbar 12, busbar 13 is a plate-shaped metal member that is elongated in one direction. Busbar 13 has a shape that is formed by inverting busbar 12 with its longitudinal direction as the axis of symmetry. Busbar 13 includes, for example, a main body 130 and an output terminal 131. Main body 130 is, for example, a rectangular plate-shaped portion. The drain terminal 63 of MOSFET 6b and the cathode terminal 71 of Zener diode 7b are electrically connected to main body 130. Output terminal 131 protrudes from one end of main body 130 in the longitudinal direction. Output terminal 131 has a through-hole 1310 extending through the main body 130 in the thickness direction. For example, a wiring member extending from an electrical component is connected to output terminal 131 using through-hole 1310. The voltage output from the drain terminal of MOSFET 6b is applied to output terminal 131. The voltage applied to the output terminal portion 131 is applied to the electric components as, for example, a power source via a wiring member.

[0166] like Figure 22 As shown, relay busbar 16 is, for example, a rectangular plate-shaped metal member. Busbars 12, 13, and 16 are, for example, located on the same plane. Busbars 12 and 13 are arranged opposite each other with their longitudinal directions parallel to each other, separated by a gap. Busbar 16 is located between busbars 12 and 13 with its longitudinal direction parallel to the longitudinal directions of busbars 12 and 13. Busbar 16 is located between the main body 120 of busbar 12 and the main body 130 of busbar 13. Busbar 16 is electrically connected to the source terminals 62 of eight MOSFETs 6 and the anode terminals 72 and 73 of two Zener diodes 7.

[0167] Insulating member 14 is a modified version of insulating member 4 of circuit structure 1A. Insulating member 14 electrically insulates bus bars 12, 13, and 16 from one another and also supports these bus bars 12, 13, and 16. Insulating member 14 is, for example, integrally molded with bus bars 12, 13, and 16. Insulating member 14 is, for example, insert-molded integrally with bus bars 12, 13, and 16.

[0168] Figure 23 1 is a schematic perspective view showing an example of an integrally molded article in which bus bars 12, 13, 16 and an insulating member 14 are integrally molded, and a wiring substrate 15. Figure 23 In FIG. 1 , the wiring substrate 15 mounted on the bus bar 16 is shown separated from the bus bar 16 .

[0169] like Figure 17 、 23 As shown in FIG. 1 , insulating member 14 includes, for example, a frame-shaped insulating portion 141. Frame-shaped insulating portion 141 surrounds body portion 120, body portion 130, and bus bar 16 therebetween. In addition to insulating portion 141, insulating member 14 also includes insulating portion 142 positioned between bus bars 12 and 16, and insulating portion 143 positioned between bus bars 13 and 16. Bus bars 12 and 16 are electrically insulated by insulating portion 142. Bus bars 13 and 16 are electrically insulated by insulating portion 143.

[0170] Wiring substrate 15 is a modified version of wiring substrate 5 of circuit structure 1A. Wiring substrate 15 is provided on busbar 16. Like wiring substrate 5, wiring substrate 15 includes, for example, insulating substrate 50 and conductive layer 51 provided on insulating substrate 50.

[0171] Two connectors 8 are provided on the wiring substrate 5. These connectors 8 include a connector 8a, which is electrically connected to the gate terminals 61 of the plurality of MOSFETs 6a via the conductive layer 51 of the wiring substrate 5; and a connector 8b, which is electrically connected to the gate terminals 61 of the plurality of MOSFETs 6b via the conductive layer 51. Each MOSFET 6a is externally switched on and off via the connector 8a. Each MOSFET 6b is externally switched on and off via the connector 8b.

[0172] In this example, one MOSFET 6a and one MOSFET 6b are arranged opposite each other. Furthermore, the MOSFETs 6a and 6b arranged opposite each other form an FET pair. Circuit structure 1B includes four FET pairs. Four conductive sheets 9 are provided corresponding to the four FET pairs. Each conductive sheet 9 is provided to reduce the resistance between the source terminal 62 of the MOSFETs 6a and 6b constituting the corresponding FET pair and the bus bar 16.

[0173] <Detailed description of circuit structure>

[0174] <Bus Bar Configuration Example>

[0175] Each of busbars 12 and 13 is made of, for example, a cladding material. Busbar 12, like busbar 2, includes a lower metal layer 250 and an upper metal layer 260. Busbar 13, like busbar 3, includes a lower metal layer 350 and an upper metal layer 360. In this example, the thickness of metal layer 250 is also set to be greater than the thickness of metal layer 260. For example, the thickness of metal layer 250 can be set to 3 mm, and the thickness of metal layer 260 can be set to 2 mm. Furthermore, the thickness of metal layer 350 is set to be greater than the thickness of metal layer 360. For example, the thickness of metal layer 350 can be set to 3 mm, and the thickness of metal layer 360 can be set to 2 mm.

[0176] The bus bar 16 is made of, for example, a cladding material, similarly to the bus bars 12 and 13. In this example, the bus bar 16 is made of, for example, two layers. Figures 19-22 As shown, busbar 16 includes a metal layer 650 on the lower surface side (also referred to as lower metal layer 650) and a metal layer 660 on the upper surface side (also referred to as upper metal layer 660). Metal layers 650 and 660 are bonded to each other by, for example, assembly rolling, cast rolling, explosive welding, overlay welding, or diffusion welding. The interface between metal layers 650 and 660 is, for example, diffusion bonded.

[0177] Busbar 16 is made of, for example, a copper and aluminum cladding material. In this example, lower metal layer 650 is, for example, an aluminum layer, and upper metal layer 660 is, for example, a copper layer. Lower metal layer 650 is made of, for example, pure aluminum. For example, pure aluminum A1050 as specified in JIS is used. Upper metal layer 660 is made of, for example, oxygen-free copper. For example, oxygen-free copper C1020 as specified in JIS is used.

[0178] The linear expansion coefficient of metal layer 650 is, for example, closer to that of insulating member 14 than that of metal layer 660. In this example, the linear expansion coefficient of metal layer 650 made of pure aluminum is, for example, 24 ppm / °C. The linear expansion coefficient of metal layer 660 made of oxygen-free copper is, for example, 17 ppm / °C.

[0179] The upper surface of bus bar 16 is generally slightly lower than the upper surfaces of bus bars 12 and 13. The upper surface of bus bar 16 is lower than the upper surfaces of bus bars 12 and 13 by, for example, the thickness of wiring board 15. The outer shape of the upper surface of bus bar 16 is substantially the same as that of wiring board 15.

[0180] A plurality of conductive protrusions 160 are provided on the upper surface of bus bar 16. Protrusions 160 are, for example, formed from a portion of bus bar 16. Specifically, protrusions 160 are, for example, formed from a portion of upper metal layer 660. In this example, protrusions 160 are formed from, for example, copper since they are part of upper metal layer 660.

[0181] The plurality of protrusions 160 are arranged in a row along the longitudinal direction of the bus bar 16. Each protrusion 160 is, for example, disk-shaped. When the wiring substrate 15 is placed on the bus bar 16, the plurality of protrusions 160 are inserted into the plurality of through holes 152 provided in the wiring substrate 15, which will be described later.

[0182] The plurality of protrusions 160 includes four protrusions 160c corresponding to the four FET pairs, respectively. Furthermore, the plurality of protrusions 160 includes two protrusions 160a corresponding to the Zener diodes 7a. Furthermore, the plurality of protrusions 160 includes two protrusions 160b corresponding to the Zener diodes 7b. The two protrusions 160a are positioned at one end of a row of the plurality of protrusions 160, while the two protrusions 160b are positioned at the other end of the row. The four protrusions 160c are positioned between the two protrusions 160a and the two protrusions 160b.

[0183] The thickness of metal layer 650 is set to be greater than that of metal layer 660. For example, the thickness of metal layer 650 can be set to 3 mm, and the thickness of the portion of metal layer 660 where protrusion 160 is located can be set to 2 mm. The electrical conductivity of metal layer 660 is greater than that of metal layer 650.

[0184] <Structural Example of Wiring Board>

[0185] like Figure 23 As shown in FIG. 1 , the wiring substrate 15 includes a plurality of through-holes 152 extending through the wiring substrate 15 in the thickness direction. The plurality of through-holes 152 are arranged in a row along the longitudinal direction of the wiring substrate 15. The plurality of through-holes 152 include a plurality of through-holes 152c corresponding to the four FET pairs. Furthermore, the plurality of through-holes 152 include two through-holes 152a corresponding to the Zener diode 7a and two through-holes 152b corresponding to the Zener diode 7b. The two through-holes 152a are located at one end of the row of through-holes 152, and the two through-holes 152b are located at the other end of the row. The four through-holes 152c are located between the two through-holes 152a and the two through-holes 152b.

[0186] A corresponding FET pair is arranged near the through-hole 152c, a Zener diode 7a is arranged near the two through-holes 152a, and a Zener diode 7b is arranged near the two through-holes 152b.

[0187] The conductive layer 51 of the wiring substrate 15 includes four conductive regions 155 corresponding to the four FET pairs. In addition, the conductive layer 51 of the wiring substrate 15 includes the two conductive regions 54 corresponding to the connectors 8a and 8b, respectively. Hereinafter, the conductive region 54 corresponding to the connector 8a will sometimes be referred to as the conductive region 54a, and the conductive region 54 corresponding to the connector 8b will sometimes be referred to as the conductive region 54b. Figures 19-21 In the figure, the conductive layer 51 is omitted.

[0188] Conductive region 155 includes lands 156a and 156b, to which gate terminals 61 of MOSFETs 6a and 6b, respectively, are connected. Furthermore, conductive region 155 includes a plurality of lands 157a, to which source terminals 62 of MOSFET 6a, respectively, are connected. Furthermore, conductive region 155 includes a plurality of lands 157b, to which source terminals 62 of MOSFET 6b, respectively, are connected. Furthermore, conductive region 155 includes an extension region 158 extending from the plurality of lands 157a and the plurality of lands 157b. In other words, the plurality of lands 157a and the plurality of lands 157b are connected via extension region 158.

[0189] The extended region 158 included in the conductive region 155 corresponding to the FET pair is located around the through-hole 152c corresponding to the FET pair. The extended region 158 is provided to surround the through-hole 152c. Alternatively, the through-hole 152c can be said to be provided within the extended region 158. The lands 157a and 157b can also be said to be protrusions protruding from the extended region 158.

[0190] In this example, the through hole 152c is, for example, a through hole having a conductive region formed on its inner circumference. On the other hand, the through holes 152a and 152b are, for example, not through holes and do not have a conductive region formed on their inner circumference. The conductive region on the inner circumference of the through hole 152c is, for example, made of metal. The conductive region on the inner circumference of the through hole 152c may be made of the same material as the conductive layer 51 or a different material. The conductive region on the inner circumference of the through hole 152c is connected to the extended region 158 surrounding the through hole 152c. In addition, the conductive region may not be formed on the inner circumference of the through hole 152c. In addition, the through holes 152a and 152b may also be through holes having a conductive region formed on their inner circumference.

[0191] Conductive regions 54a and 54b are located outside the plurality of through-holes 152. Conductive regions 54a and 54b are located at opposite ends of the wiring substrate 15 in the longitudinal direction. The two connection pads 542 of the conductive region 54a are bonded to two metal regions on the back of the connector 8a for fixing, for example, by soldering. The four connection pads 541 of the conductive region 54a are bonded to four connection terminals 81 of the connector 8a, for example, by soldering. The two connection pads 542 of the conductive region 54b are bonded to two metal regions on the back of the connector 8b, for example, by soldering. The four connection pads 541 of the conductive region 54b are bonded to four connection terminals 81 of the connector 8b, for example, by soldering.

[0192] The conductive layer 51 of the wiring substrate 15 also includes a wiring area. The wiring area includes a plurality of first wirings electrically connected to the gate terminals 61 of the plurality of MOSFETs 6a. One end of each of the first wirings is connected to a plurality of connection pads 156a to which the gate terminals 61 of the plurality of MOSFETs 6a are bonded. The other ends of each of the first wirings are connected to a plurality of connection pads 541 to which the connection terminals 81 of the connector 8a are bonded. The gate terminal 61 of the MOSFET 6a is electrically connected to the connection terminal 81 of the connector 8a via the first wirings. Furthermore, the wiring area includes a plurality of second wirings electrically connected to the gate terminals 61 of the plurality of MOSFETs 6b. One end of each of the second wirings is connected to a plurality of connection pads 156b. The other ends of each of the second wirings are connected to a plurality of connection pads 541 to which the connection terminals 81 of the connector 8b are bonded. The gate terminal 61 of the MOSFET 6b is electrically connected to the connection terminal 81 of the connector 8b via the second wirings.

[0193] Wiring substrate 15 having the above-described structure is placed on the upper surface of bus bar 16 . Figure 24 This is a diagram showing an example of a state in which wiring board 15 is placed on bus bar 16 .

[0194] When wiring substrate 15 is placed on busbar 16, protrusions 160c are inserted into through-holes 152c, protrusions 160a are inserted into through-holes 152a, and protrusions 160b are inserted into through-holes 152b. The diameter of protrusions 160 is set slightly smaller than the diameter of through-holes 152.

[0195] The wiring substrate 15 is located not only on the bus bar 16 but also on the insulating portion 142 between the bus bars 12 and 16 and on the insulating portion 143 between the bus bars 13 and 16. The wiring substrate 15 is adjacent to the main body 120 of the bus bar 12 and the main body 130 of the bus bar 13. Figures 19-21As shown, the upper end surfaces of insulating portions 142 and 143 are, for example, flush with the upper surfaces of underlying metal layers 250, 350, and 650. The upper surface of insulating substrate 50 of wiring substrate 15 on busbar 16 is flush with the upper surfaces of busbars 12 and 13. Alternatively, the upper surface of conductive layer 51 on insulating substrate 50 may be flush with the upper surfaces of busbars 12 and 13.

[0196] The wiring substrate 15 is fixed to the bus bar 16 by a bonding material, for example. As the bonding material, for example, double-sided tape is used. As the bonding material, other members can also be used. In addition, the wiring substrate 15 can also be placed on the bus bar 16 without being fixed.

[0197] The upper surface of protrusion 160 within through-hole 152 is, for example, flush with the upper surface of conductive layer 51 on insulating substrate 50 of wiring substrate 15. In this case, the upper surface of protrusion 160c within through-hole 152c is flush with the upper surface of extended region 158 surrounding through-hole 152c. Alternatively, the upper surface of protrusion 160 may be flush with the upper surface of insulating substrate 50 of wiring substrate 15.

[0198] <About Conductive Sheet>

[0199] The plurality of conductive sheets 9 are respectively bonded to the plurality of protrusions 160c exposed from the upper surface of the wiring substrate 15. In addition, the plurality of conductive sheets 9 are respectively bonded to the plurality of extended areas 158 of the wiring substrate 15. The conductive sheet 9 is provided on the wiring substrate 15 in such a manner as to cover the upper surface of the protrusion 160c in the through hole 152c of the wiring substrate 15 and the peripheral portion of the through hole 152c. The conductive sheet 9 covers the opening edge of the through hole 152c (more specifically, the opening edge on the upper surface side of the wiring substrate 15). The conductive sheet 9 is bonded to the upper surface of the protrusion 160c in the through hole 152c and the extended area 158 around the through hole 152c by the above-mentioned conductive bonding material 115 (refer to Figure 20 The conductive bonding material 115 includes a portion located between the protrusion 160 c and the extended region 158 and the conductive sheet 9 .

[0200] Alternatively, the conductive bonding material 115 may enter the through-hole 152 c . In this case, the conductive region on the inner peripheral surface of the through-hole 152 c and the protrusion 160 c in the through-hole 152 c can be bonded together via the conductive bonding material 115 .

[0201] <Example of Electronic Component Installation>

[0202] Each MOSFET 6a is mounted across both the bus bar 12 and the wiring substrate 15 on the bus bar 16. Figure 19 and20 As shown, the insulating portion 142 is located between the bus bar 12 and the bus bar 16. The MOSFET 6a is disposed on the bus bars 12 and 16 so as to straddle the insulating portion 142.

[0203] Each MOSFET 6b is mounted across both the bus bar 13 and the wiring substrate 15 on the bus bar 16. Figure 19 and 20 As shown, the insulating portion 143 is located between the bus bar 13 and the bus bar 16. The MOSFET 6b is provided on the bus bars 13 and 16 so as to straddle the insulating portion 143.

[0204] The drain terminal 63 of the MOSFET 6a is bonded to the upper surface of the bus bar 12 by the conductive bonding material 103 as described above. The voltage applied to the input terminal 121 of the bus bar 12 is applied to the drain terminal 63 of the MOSFET 6a bonded to the bus bar 12.

[0205] The drain terminal 63 of the MOSFET 6b is bonded to the upper surface of the bus bar 13 by the conductive bonding material 103 in the same manner as described above. The output voltage of the drain terminal 63 of the MOSFET 6b is output to the outside through the output terminal portion 131 of the bus bar 13.

[0206] The gate terminals 61 of the MOSFETs 6a and 6b that constitute the FET pair are bonded to the lands 156a and 156b included in the conductive region 155 corresponding to the FET pair, respectively, using a conductive bonding material 101, as described above. The gate terminal 61 of the MOSFET 6a is electrically connected to the connection terminal 81 of the connector 8a via the land 156a, the wiring region included in the conductive layer 51, and the land 541. The gate terminal 61 of the MOSFET 6b is electrically connected to the connection terminal 81 of the connector 8b via the land 156b, the wiring region included in the conductive layer 51, and the land 541. Each MOSFET 6a is externally switched on and off via the connector 8a. Each MOSFET 6b is externally switched on and off via the connector 8b.

[0207] The multiple source terminals 62 of one MOSFET 6a of the FET pair are respectively bonded to the multiple lands 157a included in the conductive region 155 corresponding to the FET pair, similarly to the above, via the conductive bonding material 102. The multiple source terminals 62 of the other MOSFET 6b of the FET pair are respectively bonded to the multiple lands 157b included in the conductive region 155 corresponding to the FET pair, via the conductive bonding material 102. The source terminal 62 of the MOSFET 6a is electrically connected to the output-side bus bar 13 via the lands 157a, the extended region 158 connected to the lands 157a, the conductive sheet 9 bonded to the extended region 158, and the conductive protrusion 160c bonded to the conductive sheet 9. Furthermore, the source terminal 62 of the MOSFET 6b is electrically connected to the output-side bus bar 13 via a land 157b, an extended region 158 connected to the land 157b, a conductive sheet 9 bonded to the extended region 158, and a conductive protrusion 160c bonded to the conductive sheet 9. The conductive sheet 9 functions as a relay terminal electrically connecting the source terminal 62 to the protrusion 160c.

[0208] The Zener diode 7a is mounted across the bus bar 12 and the wiring substrate 15 on the bus bar 16, similarly to the MOSFET 6a. The insulating portion 142 is located between the bus bar 12 and the bus bar 16. Figure 21 As shown, the Zener diode 7 a is provided on the bus bars 12 and 16 in a manner straddling the insulating portion 142 .

[0209] Zener diode 7b, like MOSFET 6b, is mounted across busbar 13 and wiring board 15 on busbar 16. Insulation portion 143 is located between busbar 13 and busbar 16. Zener diode 7b is provided on busbars 13 and 16 so as to straddle insulation portion 143.

[0210] The cathode terminal 71 of the Zener diode 7a is bonded to the upper surface of the bus bar 12 by the conductive bonding material 111 in the same manner as described above. The cathode terminal 71 of the Zener diode 7a is electrically connected to the drain terminal 63 of the MOSFET 6a via the bus bar 12.

[0211] Cathode terminal 71 of Zener diode 7b is bonded to the upper surface of bus bar 13 by conductive bonding material 111 in the same manner as described above. Cathode terminal 71 of Zener diode 7b is electrically connected to drain terminal 63 of MOSFET 6b via bus bar 13.

[0212] Anode terminal 72 of Zener diode 7a is bonded to protrusion 160a in one of two through-holes 152a provided in wiring substrate 15, similarly to the above. Anode terminal 73 of Zener diode 7a is bonded to protrusion 160a in the other of two through-holes 152a, similarly to the above, via conductive bonding material 112. Anode terminal 72 of Zener diode 7a is electrically connected to source terminal 62 of MOSFET 6a via protrusion 160a and bus bar 16.

[0213] Anode terminal 72 of Zener diode 7b is bonded to protrusion 160b in one of two through-holes 152b provided in wiring substrate 15, similarly to the above. Anode terminal 73 of Zener diode 7b is bonded to protrusion 160b in the other of two through-holes 152b, similarly to the above, via conductive bonding material 112. Anode terminals 72 and 73 of Zener diode 7b are electrically connected to source terminal 62 of MOSFET 6b via protrusion 160b and bus bar 16.

[0214] In this example, since the protrusions 160 a and 160 b are formed by a portion of the bus bar 16 , it can be said that the anode terminals 72 and 73 are joined to the upper surface of the bus bar 16 .

[0215] <An Example of a Method for Manufacturing a Circuit Structure>

[0216] When manufacturing the circuit structure 1B having the above structure, first, the three cladding materials 10 (see FIG. 1 ) for making the bus bars 12 , 13 , and 16 are prepared. Figure 10 ).

[0217] Next, the three cladding materials 10 are subjected to cold forging or cutting, etc. Figure 25 As shown, bus bars 12, 13, and 16 are manufactured.

[0218] Next, bus bars 12, 13, and 16 are placed in the insert molding die. A thermoplastic resin with excellent heat resistance, such as PPS, is then injected into the insert molding die from an injection molding machine, integrally molding the bus bars 12, 13, and 16 with the resin. This results in an integrally molded product in which the bus bars 12, 13, and 16 are integrally molded with the insulating member 14.

[0219] Next, the wiring substrate 15 is fixed to the upper surface of the bus bar 16 of the manufactured integrally molded product using a bonding material such as a double-sided tape. Figure 24 The structure shown.

[0220] Then, if Figure 26As shown in FIG. 1 , solder paste 611 is applied to predetermined areas of the upper surfaces of busbars 12, 13, 16, and wiring substrate 15. Figure 26 In the figure, the solder paste 611 is indicated by oblique lines. Then, the plurality of MOSFETs 6, the plurality of Zener diodes 7, the plurality of connectors 8 and the plurality of conductive sheets 9 are soldered relative to the area coated with the solder paste 611 by reflow soldering. Thus, the above-mentioned Figure 17 and Figure 18 The circuit structure 1B shown in FIG.

[0221] Afterwards, if Figure 27 As shown, heat sink 970 is attached to the back surfaces of busbars 12, 13, and 16 via a heat conducting member such as a heat sink. Then, housing 980, which covers wiring board 15, multiple MOSFETs 6, multiple Zener diodes 7, multiple connectors 8, and multiple conductive sheets 9, is attached to busbars 12 and 13. Thus, electrical junction box 990 is completed.

[0222] As described above, in this example, busbars 12 and 13 are made of a coating material, making it easy to connect drain terminal 63 to busbars 12 and 13, and making the overall linear expansion coefficient of busbars 12 and 13 close to the linear expansion coefficient of insulating member 14. This makes it easy to join drain terminal 63 to busbars 12 and 13, and thermal stress is less likely to be generated in the joint between drain terminal 63 and busbars 12 and 13. As a result, the reliability of this joint is improved. In addition, since the heat generated by MOSFET 6 can be directly transferred to busbars 12 and 13, local temperature increases are less likely to occur. Similarly, cathode terminal 71 is easy to join to busbars 12 and 13, and thermal stress is less likely to be generated in the joint between cathode terminal 71 and busbars 12 and 13. As a result, the reliability of this joint is improved.

[0223] Furthermore, in this example, since bus bar 16 is formed of a cladding material, it is easy to join anode terminals 72 and 73 of Zener diode 7 to bus bar 16 (specifically, protrusions 160a and 160b), and the linear expansion coefficient of bus bar 16 as a whole can be made close to the linear expansion coefficient of insulating member 14. This facilitates joining anode terminals 72 and 73 to bus bar 16, and reduces the generation of thermal stress at the joints between anode terminals 72 and 73 and bus bar 16. Consequently, the reliability of these joints is improved.

[0224] Furthermore, in this example, similar to bus bars 2 and 3 described above, bus bars 12, 13, and 16 can be easily manufactured from a cladding material by laminating multiple metal layers. Furthermore, when metal layer 250 is used as a metal layer that is more easily bonded to drain terminal 63 and cathode terminal 71 than metal layer 260, bonding of drain terminal 63 and cathode terminal 71 to metal layer 260 can be facilitated, and the linear expansion coefficient of bus bar 12 as a whole can be made closer to that of insulating member 14. Furthermore, when metal layer 350 is used as a metal layer that is more easily bonded to drain terminal 63 and cathode terminal 71 than metal layer 360, bonding of drain terminal 63 and cathode terminal 71 to metal layer 360 can be facilitated, and the linear expansion coefficient of bus bar 13 as a whole can be made closer to that of insulating member 14.

[0225] Furthermore, in this example, similar to busbars 2 and 3, busbars 12, 13, and 16 can be easily manufactured from a cladding material using aluminum and copper. Furthermore, copper is easier to bond to drain terminal 63 and cathode terminal 71 than aluminum, while aluminum has a linear expansion coefficient closer to that of insulating member 14 than copper. Therefore, it is possible to facilitate bonding of drain terminal 63 and cathode terminal 71 to metal layer 260, and the overall linear expansion coefficient of busbar 12 can be made closer to that of insulating member 14. Furthermore, it is possible to facilitate bonding of drain terminal 63 and cathode terminal 71 to metal layer 360, and the overall linear expansion coefficient of busbar 13 can be made closer to that of insulating member 14.

[0226] Furthermore, in the bus bar 12 according to this example, since the linear expansion coefficient of the metal layer 250 is closer to that of the insulating member 14 than that of the metal layer 260, a metal layer having a linear expansion coefficient close to that of the insulating member 14 can be used as the metal layer 250, regardless of the bonding performance with the drain terminal 63 and the cathode terminal 71. Similarly, a metal layer having a linear expansion coefficient close to that of the insulating member 14 can be used as the metal layer 350, regardless of the bonding performance with the drain terminal 63 and the cathode terminal 71.

[0227] In addition, in this example, the upper end surface of the insulating portion 142 of the insulating member 14 is flush with the upper surface of the lower metal layer 250 having a linear expansion coefficient close to that of the insulating member 14 (for example, see Figure 19As a result, the upper metal layer 260 of the bus bar 12 is less susceptible to deformation of the insulating portion 142 caused by changes in ambient temperature. Consequently, thermal stress is less likely to occur at the junctions between the upper metal layer 260 of the bus bar 12 and the drain terminal 63 and cathode terminal 71. Therefore, a metal layer having a large difference in linear expansion coefficient with the insulating member 14 can be used as the metal layer 260.

[0228] In addition, in this example, the upper end surface of the insulating portion 143 of the insulating member 14 is flush with the upper surface of the lower metal layer 350 having a linear expansion coefficient close to that of the insulating member 14 (for example, see Figure 19 As a result, upper metal layer 360 of bus bar 13 is less susceptible to deformation of insulating portion 143 caused by changes in ambient temperature. Consequently, thermal stress is less likely to occur in the joints between upper metal layer 360 and anode terminals 72 and 73. Therefore, a metal layer having a large difference in linear expansion coefficient with insulating member 14 can be used as metal layer 360.

[0229] In this example, the upper end surfaces of the insulating portion 142 and the insulating portion 143 are flush with the upper surfaces of the lower metal layer 250, the lower metal layer 650, and the lower metal layer 350. The lower metal layer 250, the lower metal layer 650, and the lower metal layer 350 are made of the same type of metal, for example, aluminum. Therefore, in the direction ( Figures 19 to 21 Symmetry is generated in the distribution of thermal stress (in the left and right directions), and the thermal stresses generated in the two cancel each other out. Similarly, in the direction ( Figures 19 to 21 The distribution of thermal stress (in the left and right directions) is symmetrical, and the thermal stresses generated in the two cancel each other out. As a result, the junction between the upper metal layer 260 and the drain terminal 63 and the cathode terminal 71 (for example, see Figures 19 to 21 ) is less likely to generate thermal stress, and the reliability of each joint portion is improved. Similarly, the joint portion between the wiring substrate 15 and the gate terminal 61 and the source terminal 62 on the upper metal layer 660 (for example, see Figure 19 、 Figure 20 ) is less likely to generate thermal stress, and the reliability of each joint portion is improved. Similarly, the joint portion between the upper metal layer 660 and the anode terminals 72 and 73 (for example, see Figure 21 ) is less likely to generate thermal stress, and the reliability of each joining part is improved.

[0230] In this example, since busbars 12, 13, 16 and insulating member 14 are integrally formed, no member is required to integrate busbars 12, 13, 16 and insulating member 14. Therefore, the structure of circuit structure 1B can be simplified.

[0231] Furthermore, in this example, conductive protrusion 160 protrudes from busbar 16 into through-hole 152 of wiring substrate 15. Therefore, by electrically connecting source terminal 62 on wiring substrate 15 to protrusion 160c within through-hole 152c, source terminal 62 can be easily electrically connected to busbar 16. Furthermore, by electrically connecting anode terminals 72 and 73 on wiring substrate 15 to protrusion 160 within through-hole 152, anode terminals 72 and 73 can be easily electrically connected to busbar 16.

[0232] In this example, the protrusion 160 is formed by a portion of the bus bar 16 , thereby reducing the resistance between the source terminal 62 and the bus bar 16 , and reducing the resistance between the anode terminals 72 and 73 and the bus bar 16 .

[0233] Furthermore, in this example, since the anode terminals 72 and 73 are joined to the protrusion 160 , the electrical resistance between the anode terminals 72 and 73 and the bus bar 16 can be reduced.

[0234] In addition, in this example, a conductive sheet 9 is provided, which is bonded to an extended area 158 extending from a connection plate 157a to which the source terminal 62 of the MOSFET 6a is bonded and located around the through hole 152c, and to the upper surface of a protrusion 160c within the through hole 152c. By using such a conductive sheet 9, the resistance between the source terminal 62 of the MOSFET 6a and the bus bar 16 can be reduced. In addition, the heat generated by the MOSFET 6a is easily transferred to the bus bar 16 through the conductive sheet 9, so that a local temperature rise is not easily generated. Similarly, by using this conductive sheet 9, the resistance between the source terminal 62 of the MOSFET 6a and the bus bar 16 can be reduced. In addition, the heat generated by the MOSFET 6b is easily transferred to the bus bar 16 through the conductive sheet 9, so that a local temperature rise is not easily generated.

[0235] Furthermore, in this example, the extended region 158 surrounds the periphery of the through-hole 152c, and the conductive sheet 9 covers the opening edge of the through-hole 152c. This increases the bonding area between the extended region 158 and the protrusion 160c and the conductive sheet 9. Consequently, the resistance between the source terminal 62 and the bus bar 16 can be further reduced.

[0236] Furthermore, in this example, wiring substrate 15 is located on the upper surface of busbar 16 in an area lower than the upper surfaces of busbars 12 and 13. This reduces the height difference between wiring substrate 15 and busbars 12 and 13. This makes it easier to position MOSFET 6a and Zener diode 7a across wiring substrate 15 and busbar 12. Furthermore, it is easier to position MOSFET 6b and Zener diode 7b across wiring substrate 15 and busbar 13. In this example, the entire upper surface of busbar 16 is located in an area lower than the upper surfaces of busbars 12 and 13.

[0237] Furthermore, in this example, the extended region 158 bonded to the conductive sheet 9 extends from both the land 157a bonded to the source terminal 62 of the MOSFET 6a and the land 157b bonded to the source terminal 62 of the MOSFET 6b, and is positioned around the through-hole 152c. This allows the MOSFETs 6a and 6b to share the extended region 158. This allows the resistance between the source terminal 62 of the MOSFET 6a and the bus bar 16, and the resistance between the source terminal 62 of the MOSFET 6b and the bus bar 16 to be reduced with a simple structure.

[0238] In addition, the linear expansion coefficient of the wiring substrate 15 may be closer to the linear expansion coefficient of the insulating component 14 (for example, 40 ppm / °C) than the linear expansion coefficient of the upper metal layer 260, 360, 660 (for example, 17 ppm / °C). For example, the linear expansion coefficient of the wiring substrate 15 may be 18 ppm / °C or more. In addition, the linear expansion coefficient of the wiring substrate 15 may be closer to the linear expansion coefficient of the insulating component 14 (for example, 24 ppm / °C) than the linear expansion coefficient of the lower metal layer 250, 350, 650. For example, the linear expansion coefficient of the wiring substrate 15 may be 25 ppm / °C or more. As a result, thermal stress is less likely to be generated in the joint between the wiring substrate 15 and the source terminal 62. As a result, the reliability of the joint is improved.

[0239] Alternatively, the connecting terminal of a wiring member extending from a battery can be brought into contact with the upper metal layer 260 of the input terminal portion 121 of the busbar 12. Because the conductivity of the upper metal layer 260 is greater than that of the lower metal layer 250, the resistance between the input terminal portion 121 and the battery can be reduced. Alternatively, the connecting terminal of a wiring member extending from an electrical component can be brought into contact with the upper metal layer 360 of the output terminal portion 131 of the busbar 13. Because the conductivity of the upper metal layer 360 is greater than that of the lower metal layer 350, the resistance between the output terminal portion 131 and the electrical component can be reduced.

[0240] <Other Examples of Circuit Structures>

[0241] The configuration of circuit structures 1A and 1B is not limited to the above example. For example, at least one of busbars 2, 3, 12, 13, and 16 may be formed of a cladding material comprising three or more metal layers. In this case, the topmost metal layer may be formed of a material that is easily bonded to the connection terminals of electronic components using solder or the like. For example, the topmost metal layer may be a copper layer.

[0242] Furthermore, at least one of busbars 2, 3, 12, 13, and 16 may be formed from a cladding material formed by bonding the end faces of metal layers to each other. For example, instead of laminating aluminum and copper layers, a cladding material formed by diffusion bonding the end faces of an aluminum layer to the end faces of a copper layer may be used for at least one of busbars 2, 3, 12, 13, and 16. In this case, the connection terminals of electronic components such as MOSFET 6 can be bonded to the copper layer. Furthermore, at least one of busbars 2, 3, 12, 13, and 16 may be formed from a cladding material formed by bonding the end faces of two adjacent metal layers to each other, arranged in a single direction on the same plane.

[0243] Furthermore, protrusion 302 may not be formed as a part of bus bar 3, but may be formed separately from bus bar 3. In this case, protrusion 302 may be bonded to the upper surface of bus bar 3 using a conductive bonding material such as solder. Similarly, protrusion 160 may not be formed as a part of bus bar 16, but may be formed separately from bus bar 16. In this case, protrusion 160 may be bonded to the upper surface of bus bar 16 using a conductive bonding material such as solder.

[0244] Circuit structure 1A may not include wiring substrate 5. In this case, for example, another bus bar electrically insulated from bus bars 2 and 3 by insulating member 4 may be provided. Furthermore, source terminal 62 of MOSFET 6 may be joined to bus bar 3, and gate terminal 61 of MOSFET 6 may be joined to another bus bar.

[0245] Similarly, circuit structure 1B may not include wiring substrate 15. In this case, for example, another bus bar electrically insulated from bus bars 12, 13, and 16 by insulating member 14 may be provided. Furthermore, source terminal 62 of MOSFET 6 may be joined to bus bar 16, and gate terminal 61 of MOSFET 6 may be joined to another bus bar.

[0246] Alternatively, circuit structure 1A may not include conductive sheet 9. In this case, protrusion 302 within through-hole 52 and expanded area 533 surrounding through-hole 52 may be joined by solder or the like. Similarly, circuit structure 1B may not include conductive sheet 9. In this case, protrusion 160 within through-hole 152 and expanded area 158 surrounding through-hole 152 may be joined by solder or the like.

[0247] In addition, in the circuit structure 1A, as Figure 28 As shown, the upper end surface of the peripheral portion 42a included in the insulating portion 42 may be located below the upper surfaces of the lower metal layers 250 and 350. Even in this case, the upper metal layer 260 is less susceptible to deformation of the insulating portion 42 caused by changes in ambient temperature. As a result, thermal stress is less likely to be generated at the junctions between the upper metal layer 260 and the drain terminal 63 and cathode terminal 71.

[0248] Similarly, in the circuit structure 1B, as Figure 29 As shown, the upper end surface of the insulating portion 142 may be located below the upper surface of the lower metal layer 250, 350, 650. In addition, the upper end surface of the insulating portion 143 may be located below the upper surface of the lower metal layer 250, 350, 650.

[0249] In the above example, the main body 30 of the bus bar 3 includes the upper metal layer 360 in the portion other than the protrusions 302. However, the upper metal layer 360 may not be provided in the portion other than the protrusions 302. In other words, the main body 30 may include only the plurality of protrusions 302 on the lower metal layer 350. In this case, the wiring substrate 5 is fixed to the lower metal layer 350 of the main body 30. Similarly, the bus bar 16 may include only the plurality of protrusions 160 on the lower metal layer 650.

[0250] Furthermore, the upper metal layers 260, 360, and 660 may be formed of a metal material other than copper that facilitates bonding to the drain terminal 63 and the like by soldering. Furthermore, the lower metal layers 250, 350, and 650 may be formed of a metal material other than aluminum that has a linear expansion coefficient close to that of the insulating member 14. Furthermore, to facilitate soldering of terminals to the upper metal layers 260, 360, and 660, and to reduce contact resistance between the wiring member and the input terminal portions 21 and 121, and between the wiring member and the output terminal portions 31 and 131, the upper metal layers 260, 360, and 660 may have a metal coating such as nickel on their surfaces. In this case, the upper metal layers 60, 360, and 660 may be copper layers with metal plating applied to their surfaces.

[0251] Furthermore, at least a portion of the bus bars 2, 3, 12, 13, and 16 may be made of different cladding materials. Furthermore, at least one of the bus bars 2, 3, 12, 13, and 16 may not be made of a cladding material. For example, at least one of the bus bars 2, 3, 12, 13, and 16 may be made solely of copper or other metals.

[0252] While the circuit structure has been described in detail above, the above description is in all respects illustrative and the present disclosure is not limited thereto. Furthermore, the various modifications described above may be combined and applied as long as they do not conflict with each other. Furthermore, it should be understood that numerous modifications not illustrated are conceivable without departing from the scope of the present disclosure.

[0253] Description of labels

[0254] 1A, 1B circuit structure

[0255] 2, 12 Input side busbars

[0256] 3.13 Output side busbar

[0257] 4.14 Insulation components

[0258] 5. Wiring board

[0259] 6.7 Electronic components

[0260] 7a, 7b Zener diodes

[0261] 8, 8a, 8b, 911, 912 connectors

[0262] 9 Conductive sheet

[0263] 10. Cladding material

[0264] 10a, 10b, 250, 260, 350, 360, 650, 660 metal layers

[0265] 11 Solder paste

[0266] 15 Wiring board

[0267] 16 Relay Bus

[0268] 20, 30, 65, 75, 120, 130 main body

[0269] 21, 121 Input terminal

[0270] 31, 131 Output terminal

[0271] 41, 42, 141, 142, 143 insulation parts

[0272] 42a surrounding part

[0273] 50 Insulating substrate

[0274] 51 conductive layer

[0275] 52, 52a, 52b, 310, 1210, 1310 through holes

[0276] 53, 54, 54a, 54b, 155 conductive areas

[0277] 55 Wiring area

[0278] 60, 70 package

[0279] 61 Gate terminal

[0280] 62 source terminal

[0281] 63 Drain terminal

[0282] 63a convex part

[0283] 71 cathode terminal

[0284] 72, 73 Anode terminals

[0285] 81 connection terminals

[0286] 101, 102, 103, 111, 112, 115 conductive bonding materials

[0287] 152, 152a, 152b, 152c, 210 through holes

[0288] 156a, 156b, 157a, 157b, 531, 532, 541, 542 connection plates

[0289] 158, 533 expansion area

[0290] 160, 160a, 160b, 160c, 302, 302a, 302b protrusions

[0291] 201 Part 1

[0292] 202 Part 2

[0293] 301 substrate mounting area

[0294] 551 Wiring

[0295] 611 solder paste

[0296] 900, 990 electrical junction boxes

[0297] 910 control board

[0298] 920, 970 Radiator

[0299] 930, 980 housing

Claims

1. A circuit structure comprising: a first bus bar formed of a cladding material; Second bus bar; an insulating member including an insulating portion located between the first bus bar and the second bus bar; and an electronic component disposed on the first bus bar and the second bus bar in a manner straddling the insulating portion; The electronic component has a connection terminal joined to the first bus bar, The first bus bar has: a first metal layer; and a second metal layer stacked on the first metal layer in a thickness direction of the first bus bar, The connecting terminal is bonded to the second metal layer, The first metal layer is an aluminum layer, The second metal layer is a copper layer or a copper layer with metal plating applied on the surface. The thickness of the first metal layer is greater than the thickness of the second metal layer, The first bus bar, the second bus bar and the insulating member are integrally formed. The linear expansion coefficient of the first metal layer is closer to the linear expansion coefficient of the insulating member than the linear expansion coefficient of the second metal layer.

2. The circuit structure according to claim 1, wherein An upper end surface of the insulating portion is flush with an upper surface of the first metal layer or is located below the upper surface.

3. The circuit structure according to claim 1 or 2, wherein: The second bus bar is made of a cladding material.

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