Wiring board

Abstract

A wiring board (10) is provided with a substrate part (11) and a conductor part (12). The substrate section (11) is provided with a conductor layer (20) having a wiring pattern (first wiring pattern (21)), and an insulating layer (30) having an insulating film (32) covering a part of the wiring pattern, and a partial region of the wiring pattern is configured as a pad section (23). The conductor part (12) has a base material (40) and a plating layer (41). The base material (40) has an opposing surface (42), a pair of first surfaces (43, 44), and a pair of second surfaces (45, 46). The facing surface (42) and the pair of first surfaces (43, 44) are covered with a plating layer (41). The pair of second surfaces (45, 46) have exposed surfaces (45A, 46A). A plating layer (41) covering the pair of first surfaces (43, 44) is bonded to the pad portion (23). The pair of second surfaces (45, 46) are disposed so as to overlap the pad section (23) in the thickness direction.

Description

Technical Field

[0001] The present invention relates to a wiring substrate. Background Art

[0002] Patent document 1 discloses a heat dissipation structure of a surface mounted electronic component. Specifically, a heat generating component mounted on a printed circuit board and an SMT heat sink disposed on a wiring pattern near the heat generating component are disclosed. The SMT heat sink is made of metal with good thermal conductivity and functions as a heat dissipation component. The SMT heat sink is in a rectangular parallelepiped shape, and the lower surface is soldered to the wiring pattern. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2003-188565 Summary of the invention Problems to be solved by the invention

[0004] The conductor part such as the SMT heat sink in Patent Document 1 is composed of, for example, a base material and a plating layer covering the base material, and the plating layer is soldered to the wiring pattern. Such a conductor part is bonded to the wiring pattern not only on the lower surface but also on the four surfaces rising from the lower surface, thereby further improving the bonding strength relative to the wiring pattern. However, in order to bond the above four surfaces to the wiring pattern, it is necessary to form the pad part formed by the exposed part of the wiring pattern to extend outward from the outer peripheral edge of the lower surface of the conductor part, and to bond the above four surfaces to the extended part. Therefore, it is difficult to arrange the base material close to the end of the pad part.

[0005] One of the objects of the present invention is to provide a technique for improving the bonding strength of a conductor portion to a wiring pattern and facilitating the approach of a base material of the conductor portion to an end portion of a pad portion in a predetermined direction. Solutions to Solve Problems

[0006] The wiring substrate of the present disclosure includes a substrate portion and a conductor portion. The substrate portion includes a conductor layer and an insulating layer, the conductor layer has a wiring pattern, the insulating layer has an insulating film covering a portion of the wiring pattern, and a portion of the wiring pattern is configured as a pad portion not covered by the insulating film. The conductor portion is joined to the pad portion by solder, in, The conductor portion includes a conductive base material and a plating layer covering a portion of the base material. The substrate comprises: an opposing surface facing the pad portion on one side in the thickness direction of the substrate portion; a pair of first surfaces arranged on both sides of a first direction orthogonal to the thickness direction; and a pair of second surfaces arranged on both sides of a second direction orthogonal to the thickness direction and the first direction. The opposing surface and the pair of first surfaces are covered with the plating layer, The pair of second surfaces has an exposed surface where the substrate is not covered by the plating layer and is exposed, The plating layer covering the pair of first surfaces is bonded to the pad portion via the solder, The pair of second surfaces is arranged to overlap with the pad portion in the thickness direction. Effects of the Invention

[0007] The technology disclosed in the present disclosure can improve the bonding strength of the conductor portion to the wiring pattern and can easily bring the base material of the conductor portion closer to the end of the pad portion in a predetermined direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a top view of the wiring substrate in the first embodiment. Figure 2 It is a front view of the wiring substrate in the first embodiment. Figure 3 The conductor part is surrounded by Figure 1 A cross-sectional view taken along line AA. Figure 4 The conductor part is surrounded by Figure 2 A cross-sectional view taken along line BB. Figure 5 This is an enlarged plan view of the periphery of the conductor portion of the wiring board in the second embodiment. Figure 6 yes Figure 5 CC line section view. Figure 7 This is an enlarged plan view of the periphery of the conductor portion of the wiring board in the third embodiment. Figure 8 yes Figure 7 DD line cross-sectional view. DETAILED DESCRIPTION

[0009] Hereinafter, embodiments of the present disclosure are listed and exemplified.

[0010] [1] A wiring board comprising a substrate portion and a conductor portion, The substrate portion includes a conductor layer and an insulating layer, the conductor layer has a wiring pattern, the insulating layer has an insulating film covering a portion of the wiring pattern, and a portion of the wiring pattern is configured as a pad portion not covered by the insulating film. The conductor portion is joined to the pad portion by solder, in, The conductor portion includes a conductive base material and a plating layer covering a portion of the base material. The substrate comprises: an opposing surface facing the pad portion on one side in the thickness direction of the substrate portion; a pair of first surfaces arranged on both sides of a first direction orthogonal to the thickness direction; and a pair of second surfaces arranged on both sides of a second direction orthogonal to the thickness direction and the first direction. The opposing surface and the pair of first surfaces are covered with the plating layer, The pair of second surfaces has an exposed surface where the substrate is not covered by the plating layer and is exposed, The plating layer covering the pair of first surfaces is bonded to the pad portion via the solder, The pair of second surfaces is arranged to overlap with the pad portion in the thickness direction.

[0011] The wiring substrate can achieve an improvement in the bonding strength of the conductor portion relative to the pad portion because the plating covering the pair of first surfaces is bonded to the pad portion by solder. On the other hand, the pair of second surfaces is configured to have an exposed surface and overlap the pad portion in the thickness direction. That is, the wiring substrate is not easily interfered with other components because at least a portion of the pair of second surfaces is not covered by the plating, and as a result, it is easy to make the substrate close to the end of the second direction of the pad portion.

[0012] [2] In the wiring substrate described in [1], A distance in the second direction from at least any one of the second surfaces to an end of the pad portion is shorter than a distance in the first direction from any one of the first surfaces to an end of the pad portion.

[0013] The wiring substrate can make at least one of the second surfaces closer to the end of the pad portion in the second direction than the distance from any of the first surfaces to the end of the pad portion in the first direction.

[0014] [3] In the wiring substrate described in [1] or [2], The conductor portion is arranged across the plurality of pad portions that are separated from each other, and is joined to each of the plurality of pad portions.

[0015] The wiring substrate can connect the conductor portion at multiple locations in a focused manner.

[0016] [4] In the wiring substrate described in [3], The solder is continuously arranged between the substrate portion and the opposing surface so as to straddle the plurality of separated land portions.

[0017] The wiring substrate can focus on bonding the conductor portion at multiple locations, and can improve the bonding strength of the entire solder by continuously placing the solder across the plurality of land portions.

[0018] [5] In the wiring substrate described in any one of [1] to [4], The entire facing surface of the conductor portion is provided so as to overlap with the pad portion.

[0019] The wiring substrate can easily achieve uniform bonding strength with the pad portion over the entire facing surface.

[0020] [6] In the wiring substrate described in any one of [1] to [5], The area of ​​each of the pair of first surfaces is larger than the area of ​​either of the pair of second surfaces.

[0021] The above wiring board can easily improve the bonding strength between the first surface and the pad portion while suppressing the increase in size of the conductor portion.

[0022] [7] In the wiring substrate described in any one of [1] to [6], The conductor part is formed in a long strip shape extending in the direction of current flow at a portion where the conductor part is joined.

[0023] The wiring substrate can improve the heat dissipation performance of the conductor portion because current can easily flow to the conductor portion.

[0024] [8] In the wiring substrate described in any one of [1] to [7], A fillet of the solder joined to at least any one of the first surface and the land portion has a height from the land portion higher than a height from the land portion of a center position in the thickness direction of the first surface joined to the fillet.

[0025] The above wiring substrate can further improve the bonding strength between at least any one of the first surfaces and the pad portion.

[0026] <First Embodiment> Figure 1 The wiring board 10 shown is installed in, for example, a vehicle (not shown). The wiring board 10 is provided between a power supply unit 90 and a load 91 installed in the vehicle, and functions as a power path for supplying power from the power supply unit 90 to the load 91 side.

[0027] like Figure 1 and Figure 2 As shown in FIG. 1 , the wiring substrate 10 includes a substrate portion 11, a conductor portion 12, an input portion 13, an output portion 14, a switch portion 15, and solder 16. Figure 1 The solder 16 is omitted.

[0028] The substrate 11 includes a conductor layer 20 and an insulating layer 30. The conductor layer 20 is provided between the power supply 90 and the load 91 and functions as a power path for supplying power from the power supply 90 to the load 91. The conductor layer 20 includes an input unit 13, an output unit 14, and a switch unit 15.

[0029] The input unit 13, the output unit 14, and the switch unit 15 are electrically connected to the conductor layer 20, for example, by soldering. The input unit 13 is configured as a connector, for example, and is connected to the power supply unit 90 via the wiring 92. The power supplied to the input unit 13 is supplied to the output unit 14 via the conductor layer 20.

[0030] The output unit 14 is configured as, for example, a connector, and is connected to the load 91 via the wiring 93. The power from the power supply unit 90 is supplied to the load 91 via the input unit 13, the conductor layer 20, and the output unit 14.

[0031] The switch unit 15 may be a switch having physical contacts or a semiconductor switch element. The switch unit 15 is provided between the input unit 13 and the output unit 14. When the switch unit 15 is in the on state, the power supply from the input unit 13 side to the output unit 14 side is allowed. When the switch unit 15 is in the off state, the power supply from the input unit 13 side to the output unit 14 side is cut off.

[0032] The conductor layer 20 is made of, for example, a metal foil (e.g., copper foil). The conductor layer 20 has a first wiring pattern 21 and a second wiring pattern 22. The first wiring pattern 21 and the second wiring pattern 22 are arranged to be separated from each other. The first wiring pattern 21 is in a long strip shape. An input portion 13 is provided at one end side of the first wiring pattern 21. One end of a switch portion 15 is provided at the other end side of the first wiring pattern 21. The other end of the switch portion 15 and the output portion 14 are provided at the second wiring pattern 22.

[0033] The insulating layer 30 includes a substrate body 31 and an insulating film 32. The substrate body 31 has insulating properties and is made of, for example, resin. The substrate body 31 is in the shape of a plate. The substrate body 31 is arranged on one side of the thickness direction of the substrate portion 11 relative to the conductor layer 20. Hereinafter, "the thickness direction of the substrate portion 11" will be referred to as "the thickness direction". The conductor layer 20 (more specifically, the first wiring pattern 21 and the second wiring pattern 22) is provided on the surface on the other side of the thickness direction of the substrate body 31. The insulating film 32 covers a portion of the surface on the other side of the thickness direction of the conductor layer 20 (more specifically, the first wiring pattern 21 and the second wiring pattern 22). The insulating film 32 is, for example, configured as a solder resist. The insulating film 32 has insulating properties and is made of, for example, resin.

[0034] A part of the area of ​​the first wiring pattern 21 is formed as a pad portion 23 that is not covered by the insulating film 32. The pad portion 23 is surrounded by the insulating film 32. The pad portion 23 is rectangular. The pad portion 23 is in the shape of a long strip extending along the direction of current flow. The pad portion 23 is in the shape of a long strip extending along the long side direction of the first wiring pattern 21. The pad portion 23 is arranged between the input portion 13 and the output portion 14, and between the input portion 13 and the switch portion 15. A plurality of pad portions 23 are provided. The plurality of pad portions 23 are arranged to be separated from each other. The plurality of pad portions 23 are separated in the direction of current flow. The plurality of pad portions 23 are separated in the long side direction of the first wiring pattern 21.

[0035] like Figure 3 and Figure 4 As shown, the conductor portion 12 is a member joined to the pad portion 23 by the solder 16. The conductor portion 12 functions as a heat dissipation member. The conductor portion 12 is configured as a chip busbar, for example. In the present embodiment, the conductor portion 12 is in the shape of a rectangular parallelepiped, but may be in other forms. For example, the conductor portion 12 may be in the shape of a cube or may be in a form including a curved surface. The conductor portion 12 includes a conductive substrate 40 and a plating layer 41 covering a portion of the substrate 40. The substrate 40 is a member that is not joined to the solder 16, or a member that is more difficult to join to the solder 16 than the plating layer 41. The plating layer 41 is a member that is joined to the solder 16, and is a member that is easier to join to the solder 16 than the substrate 40.

[0036] The substrate 40 has an opposing surface 42 , a pair of first surfaces 43 , 44 , a pair of second surfaces 45 , 46 , and a top surface 47 .

[0037] The facing surface 42 faces the land portion 23 in one side in the thickness direction. The facing surface 42 faces the conductor layer 20 directly or via the solder 16. The facing surface 42 may or may not be in contact with the conductor layer 20.

[0038] The pair of first surfaces 43 and 44 are arranged on both sides of the substrate 40 in the first direction. The first direction is a direction perpendicular to the thickness direction. One first surface 43 is arranged on one side of the substrate 40 in the first direction. The other first surface 44 is arranged on the other side of the substrate 40 in the first direction.

[0039] The pair of second surfaces 45 and 46 are arranged on both sides of the substrate 40 in the second direction. The second direction is a direction perpendicular to the thickness direction and the first direction. One second surface 45 is arranged on one side of the substrate 40 in the second direction, and the other second surface 46 is arranged on the other side of the substrate 40 in the second direction.

[0040] The top surface 47 is arranged on the side of the base material 40 opposite to the facing surface 42. The top surface 47 is arranged on the other side of the base material 40 in the thickness direction.

[0041] The length of the conductor part 12 in the first direction is shorter than the length of the conductor part 12 in the second direction. The length of the conductor part 12 in the thickness direction is shorter than the length of the conductor part 12 in the first direction and shorter than the length in the second direction.

[0042] The opposing surface 42, the pair of first surfaces 43, 44, the pair of second surfaces 45, 46, and the top surface 47 are flat surfaces. Flat surfaces include not only strictly flat surfaces but also slightly curved surfaces. The opposing surface 42, the pair of first surfaces 43, 44, and the top surface 47 are covered with the plating layer 41. The plating layer 41 covering the opposing surface 42, the pair of first surfaces 43, 44, and the top surface 47 is continuous and annular. The plating layer 41 covering the opposing surface 42 and the pair of first surfaces 43, 44 is joined to the pad portion 23 through the solder 16. That is, the opposing surface 42 and the pair of first surfaces 43, 44 are joined to the solder 16 via the plating layer 41.

[0043] On the projection plane of the opposing surface 42, the solder 16 and the pad portion 23 projected onto an imaginary plane orthogonal to the thickness direction, the ratio of the area of ​​the region where the opposing surface 42, the solder 16 and the pad portion 23 overlap with each other to the area of ​​the opposing surface 42 is preferably 50% or more, more preferably 80% or more. According to this structure, the wiring substrate 10 can further improve the bonding strength between the conductor portion 12 and the pad portion 23. In the present embodiment, the above ratio is 100% (refer to Figure 1 , Figure 3 , Figure 4 ).

[0044] The pair of second surfaces 45 and 46 have exposed surfaces 45A and 46A where the base material 40 is not covered by the plating layer 41 and is exposed. In the present embodiment, the entire second surfaces 45 and 46 are the exposed surfaces 45A and 46A. The exposed surfaces 45A and 46A are not bonded to the solder 16 and are not bonded to the pad portion 23. The pair of second surfaces 45 and 46 are arranged to overlap with the pad portion 23 in the thickness direction.

[0045] According to this structure, the wiring substrate 10 can improve the bonding strength of the conductor part 12 to the pad part 23 because the plating layer 41 covering the pair of first surfaces 43 and 44 is bonded to the pad part 23 through the solder 16. On the other hand, the pair of second surfaces 45 and 46 are configured to have exposed surfaces 45A and 46A and overlap the pad part 23 in the thickness direction. That is, the wiring substrate 10 is not easily interfered with other components because at least a part of the pair of second surfaces 45 and 46 is not covered by the plating layer 41. As a result, it is easy to bring the base material 40 close to the end parts 23C and 23D of the pad part 23 in the second direction. In particular, the wiring substrate 10 of the present embodiment is easy to bring the base material 40 close to the end parts 23C and 23D of the pad part 23 in the second direction because the entire second surfaces 45 and 46 are exposed surfaces 45A and 46A.

[0046] The distance in the second direction from at least any one of the second surfaces 45 and 46 to the end of the pad portion 23 is shorter than the distance in the first direction from any one of the first surfaces 43 and 44 to the end of the pad portion 23. The "end of the pad portion 23" of "from the second surface 45 to the end of the pad portion 23" refers to "end 23C of the pad portion 23 arranged in the direction that the second surface 45 is facing". The "end of the pad portion 23" of "from the second surface 46 to the end of the pad portion 23" refers to "end 23D of the pad portion 23 arranged in the direction that the second surface 46 is facing". The "end of the pad portion 23" of "from the first surface 43 to the end of the pad portion 23" refers to "end 23A of the pad portion 23 arranged in the direction that the first surface 43 is facing". The “end portion of the pad portion 23 ” in “from the first surface 44 to the end portion of the pad portion 23 ” means “the end portion 23B of the pad portion 23 arranged in the direction in which the first surface 44 faces”.

[0047] exist Figure 3 In the example shown, the distance in the first direction from the first surface 43 to the end 23A of the pad portion 23 is the distance L1, and the distance in the first direction from the first surface 44 to the end 23B of the pad portion 23 is the distance L2. Figure 4 In the example shown, the distance in the second direction from the second surface 45 to the end 23C of the pad portion 23 is the distance L3, and the distance in the second direction from the second surface 46 to the end 23D of the pad portion 23 is the distance L4. The distance L3 is shorter than the distance L1 and shorter than the distance L2. The distance L4 is shorter than the distance L1 and shorter than the distance L2. That is, the distances L3 and L4 in the second direction from the second surfaces 45 and 46 to the ends 23C and 23D of the pad portion 23 are both shorter than any of the distances L1 and L2 in the first direction from the first surfaces 43 and 44 to the ends 23A and 23B of the pad portion 23.

[0048] According to this structure, the wiring substrate 10 can bring the second surface 45 closer to the end 23C in the second direction of the pad portion 23 than the distances L1 and L2. In addition, the wiring substrate 10 can bring the second surface 46 closer to the end 23D in the second direction of the pad portion 23 than the distances L1 and L2.

[0049] Furthermore, the distance L1 may be the same as or different from the distance L2, and the distance L3 may be the same as or different from the distance L4.

[0050] Solder fillets 51, 52, 53, and 54 are formed on the solder 16. The solder fillet 51 is arranged on one side of the solder 16 in the first direction. The solder fillet 51 is bonded to the first surface 43 and the land portion 23. The solder fillet 52 is arranged on the other side of the solder 16 in the first direction. The solder fillet 52 is bonded to the first surface 44 and the land portion 23. The solder fillet 53 is arranged on one side of the solder 16 in the second direction. Figure 4In the example shown, the solder fillet 53 is arranged below the exposed surface 45A of the second surface 45. In addition, the solder fillet 53 may not be arranged below the exposed surface 45A of the second surface 45. For example, the upper end of the solder fillet 53 may be arranged above the lower end of the exposed surface 45A. The solder fillet 54 is arranged on the other side of the solder 16 in the second direction. Figure 4 In the example shown, the weld leg 54 is arranged below the exposed surface 46A of the second surface 46. In addition, the weld leg 54 may not be arranged below the exposed surface 46A of the second surface 46. For example, the upper end of the weld leg 54 may be arranged above the lower end of the exposed surface 46A. The height of the weld leg 51 is the same as the height of the weld legs 53 and 54, or higher than the height of the weld legs 53 and 54. The height of the weld leg 52 is the same as the height of the weld legs 53 and 54, or higher than the height of the weld legs 53 and 54. The cross-section of the weld legs 51 and 52 (more specifically, the cross-section cut in the direction perpendicular to the second direction) is a triangular shape (more specifically, an isosceles triangle with equal lengths of the two sides to be joined). The cross-section of the weld legs 53 and 54 (more specifically, the cross-section cut in the direction perpendicular to the first direction) is a triangular shape (more specifically, an isosceles triangle with equal lengths of the two sides to be joined). “The lengths of both sides are the same” includes not only the case where they are strictly the same but also the case where they are substantially the same. “Substantially the same” means that the ratio of the difference in the lengths of the two sides to the length of the longer side is within 10%.

[0051] exist Figure 3 In the example shown, the height of the solder leg 51 of the solder 16 joined to the first surface 43 and the pad portion 23 from the pad portion 23 is height H1. Height H1 refers to the height of the highest position of the solder leg 51. The height of the solder leg 52 of the solder 16 joined to the first surface 44 and the pad portion 23 from the pad portion 23 is height H2. Height H2 refers to the height of the highest position of the solder leg 52. The height of the center position of the first surface 43 in the thickness direction from the pad portion 23 is height HC1. Height HC1 refers to the height of the center position of the first surface 43 in the second direction. The height of the center position of the first surface 44 in the thickness direction from the pad portion 23 is height HC2. Height HC2 refers to the height of the center position of the first surface 44 in the second direction. The height is synonymous with the length in the thickness direction.

[0052] exist Figure 3 In the example shown, the height H1 is higher than the height HC1. The height H2 is higher than the height HC2. With this structure, the wiring substrate 10 can further improve the bonding strength between the first surfaces 43 and 44 and the pad portion 23.

[0053] In addition, the height H1 may be the same as the height HC1 or lower than the height HC1. The height H2 may be the same as the height HC2 or lower than the height HC2. The height H1 may be higher than the height HC1, and the height H2 may be the same as the height HC2 or lower than the height HC2. The height H2 may be higher than the height HC2, and the height H1 may be the same as the height HC1 or lower than the height HC1.

[0054] The conductor portion 12 is joined to one pad portion 23. In the plane direction perpendicular to the thickness direction, the conductor portion 12 is arranged inside the outer periphery of the pad portion 23. The entire facing surface 42 of the conductor portion 12 is provided so as to overlap with the pad portion 23. According to this structure, the bonding strength of the wiring substrate 10 with the pad portion 23 is easily uniform over the entire facing surface 42.

[0055] The area of ​​each of the pair of first surfaces 43 and 44 is larger than the area of ​​any of the pair of second surfaces 45 and 46. With this configuration, the wiring board 10 can easily improve the bonding strength between the first surfaces 43 and 44 and the pad portion 23 while suppressing an increase in the size of the conductor portion 12.

[0056] The conductor portion 12 is formed in a strip shape extending in the direction of current flow at the portion where the conductor portion 12 is joined. The "direction of current flow" is the direction from the input portion 13 side toward the output portion 14 side in the conductor layer 20. According to this structure, the wiring substrate 10 can improve the heat dissipation performance of the conductor portion 12 because the current easily flows to the conductor portion 12.

[0057] The following description relates to a method for manufacturing the wiring substrate 10 . The substrate portion 11 is formed by printing the conductor layer 20 on the surface of the substrate body 31 and applying the insulating film 32 in a manner that covers a portion of the conductor layer 20. The conductor portion 12 is formed by cutting and dividing the metal member in a direction orthogonal to its own extension direction after the surface of the prism-shaped metal member is plated. The cut surface is constituted as the second surface 45, 46 that is not plated. Solder paste is applied to the substrate portion 11, and the conductor portion 12, the input portion 13, the output portion 14, and the switch portion 15 are placed. Then, by reflow soldering, the conductor portion 12, the input portion 13, the output portion 14, and the switch portion 15 are bonded to the conductor layer 20 through the solder 16. In this way, the wiring substrate 10 can be manufactured.

[0058] <Second Embodiment> In the first embodiment, a structure in which one conductor portion is joined to one pad portion is described. In contrast, in the second embodiment, a structure in which one conductor portion is joined to a plurality of pad portions is described. In addition, in the description of the second embodiment, the same reference numerals are given to the same structures as those in the first embodiment, and detailed description is omitted.

[0059] exist Figure 5 and Figure 6 2 shows a wiring substrate 210 of the second embodiment. The wiring substrate 210 includes a substrate portion 211, a conductor portion 12, and solder 216. The substrate portion 211 includes a conductor layer 20 and an insulating layer 230. Figure 5 The solder 216 is omitted.

[0060] like Figure 5 and Figure 6 As shown, the insulating layer 230 includes a substrate body 31 and an insulating film 232. The insulating film 232 has insulating properties and is made of, for example, resin. The insulating film 232 covers a portion of the other side of the conductor layer 20 (more specifically, the first wiring pattern 21) in the thickness direction.

[0061] A part of the first wiring pattern 21 in the conductor layer 20 is formed as pad portions 223A and 223B which are not covered by the insulating film 232. The pad portions 223A and 223B are respectively surrounded by the insulating film 232. The pad portions 223A and 223B are respectively rectangular. The pad portions 223A and 223B are arranged at intervals in the direction of current flow. The pad portions 223A and 223B are arranged at intervals in the long side direction of the first wiring pattern 21. The pad portions 223A and 223B are arranged between the input portion 13 and the output portion 14 described in the first embodiment, and are arranged between the input portion 13 and the switch portion 15.

[0062] The conductor portion 12 is arranged across a plurality of (two in the present embodiment) pad portions 223A and 223B separated from each other, and is joined to each of the plurality of pad portions 223A and 223B by solder 216. According to this structure, the wiring substrate 210 can make the conductor portion 12 be joined at multiple locations. The plurality of (two in the present embodiment) pad portions 223A and 223B joined by one conductor portion 12 are composed of the same wiring pattern (specifically, the first wiring pattern 21). The pad portion 223A on one side is arranged on the second direction side compared to the pad portion 223B on the other side. The second surface 45 is arranged to overlap with the pad portion 223A in the thickness direction. The second surface 46 is arranged to overlap with the pad portion 223B in the thickness direction.

[0063] The solder 216 is continuously arranged between the substrate portion 211 (more specifically, the substrate body 31) and the opposing surface 42 so as to straddle the separated plurality of pad portions 223A and 223B. The insulating film 232 has an intermediate insulating film 232A, and the intermediate insulating film 232A is arranged between the plurality of pad portions 223A and 223B to which one conductor portion 12 is joined. The solder 216 has a first solder portion 216A that joins the plating layer 41 covering the opposing surface 42 to the pad portion 223A; a second solder portion 216B that joins the plating layer 41 covering the opposing surface 42 to the pad portion 223B; and a third solder portion 216C that is arranged between the first solder portion 216A and the second solder portion 216B. The first solder portion 216A is arranged to overlap the opposing surface 42 and the pad portion 223A in the thickness direction. The second solder portion 216B is arranged to overlap the opposing surface 42 and the pad portion 223B in the thickness direction. The conductor portion 12 and the intermediate insulating film 232A are arranged to be spaced apart in the thickness direction. The third solder portion 216C is arranged between the conductor portion 12 and the intermediate insulating film 232A in the thickness direction, and connects the first solder portion 216A and the second solder portion 216B. The third solder portion 216C is bonded to the plating layer 41 covering the opposing surface 42.

[0064] According to this structure, the wiring substrate 210 can focus on bonding the conductor portion 12 at multiple locations, and the solder 216 is continuously arranged across the plurality of land portions 223A and 223B, thereby improving the bonding strength of the entire solder 216 .

[0065] <Third Embodiment> In the second embodiment, as a structure in which a conductor portion is joined to a plurality of pad portions, an example in which the plurality of pad portions are composed of the same wiring pattern is described. In the third embodiment, an example in which the plurality of pad portions are composed of different wiring patterns is described. In addition, in the description of the third embodiment, the same reference numerals are given to the same structures as those in the first embodiment, and detailed description is omitted.

[0066] exist Figure 7 and Figure 8 3 shows a wiring substrate 310 of the third embodiment. The wiring substrate 310 includes a substrate portion 311, a conductor portion 12, and solder 316. The substrate portion 311 includes a conductor layer 320 and an insulating layer 330. Figure 7 Solder 316 is omitted.

[0067] The conductor layer 320 has a plurality of (two in this embodiment) wiring patterns 321A and 321B connected to one conductor portion 12. The plurality of wiring patterns 321A and 321B constitute a path between the input portion 13 and the switch portion 15 described in the first embodiment (see Figure 1). The plurality of wiring patterns 321A and 321B are arranged to be separated from each other in the second direction. A space is formed between the plurality of wiring patterns 321A and 321B. One wiring pattern 321A is arranged on the second direction side relative to the other wiring pattern 321B.

[0068] like Figure 7 and Figure 8 As shown, the insulating layer 330 includes the substrate body 31 and an insulating film 332. The insulating film 332 has insulating properties and is made of, for example, resin. The insulating film 332 covers a portion of the other side of the conductor layer 320 (more specifically, the wiring patterns 321A and 321B) in the thickness direction.

[0069] A part of the wiring pattern 321A is configured as a pad portion 323A not covered by the insulating film 322. A part of the wiring pattern 321B is configured as a pad portion 323B not covered by the insulating film 322. The pad portions 323A and 323B are each rectangular. The pad portions 323A and 323B are arranged to be separated from each other in the direction in which current flows.

[0070] The conductor portion 122 is arranged across a plurality of (two in the present embodiment) pad portions 323A and 323B separated from each other, and is joined to each of the plurality of pad portions 323A and 323B by solder 316. According to this structure, the wiring substrate 310 can join the conductor portion 12 at multiple locations. The plurality of (two in the present embodiment) pad portions 323A and 323B joined by one conductor portion 12 are composed of different wiring patterns. The pad portion 323A of one side is arranged on the second direction side than the pad portion 323B of the other side. The second surface 45 is arranged overlapping with the pad portion 323A in the thickness direction. The second surface 46 is arranged overlapping with the pad portion 323B in the thickness direction.

[0071] The solder 316 is continuously arranged between the substrate portion 311 (more specifically, the substrate body 31) and the opposing surface 42 so as to straddle the separated plurality of pad portions 323A and 323B. The solder 316 includes: a first solder portion 316A that joins the plating layer 41 covering the opposing surface 42 to the pad portion 323A; a second solder portion 316B that joins the plating layer 41 covering the opposing surface 42 to the pad portion 323B; and a third solder portion 316C that is arranged between the first solder portion 316A and the second solder portion 316B. The first solder portion 316A is arranged to overlap the opposing surface 42 and the pad portion 323A in the thickness direction. The second solder portion 316B is arranged to overlap the opposing surface 42 and the pad portion 323B in the thickness direction. The third solder portion 316C is arranged above the space between the plurality of wiring patterns 321A and 321B. The third solder portion 316C connects the first solder portion 316A and the second solder portion 316B. The third solder portion 316C is bonded to the plating layer 41 covering the opposing surface 42. The solder 316 forms a bridge across the plurality of land portions 323A and 323B.

[0072] According to this structure, the wiring substrate 310 joins the conductor part 12 at multiple locations, and the solder 316 is continuously arranged across the plurality of pad parts 323A and 323B, thereby improving the overall joining strength of the solder 316. In addition, the conductor part 12 also functions as a path connecting the wiring pattern 321A and the wiring pattern 321B.

[0073] <Other Implementation Methods> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the features of the embodiments described above or below can be combined in any way within the scope of non-contradiction. In addition, any feature in the embodiments described above or below can be omitted if it is not clearly indicated as a necessary feature. Furthermore, the embodiments described above can also be modified as follows.

[0074] The length of the conductor part 12 in the first direction may be longer than the length of the conductor part 12 in the second direction, or may be the same as the length of the conductor part 12 in the second direction. Here, "same" is not limited to being strictly the same, but also includes being substantially the same. Substantially the same means that the ratio of the difference between the length in the first direction and the length in the second direction to the length of the longer side is within 5%.

[0075] The length of the conductor part 12 in the thickness direction may be longer than the length of the conductor part 12 in the first direction, or may be the same as the length of the conductor part 12 in the first direction. Here, "same" is not limited to being strictly the same, but also includes being substantially the same. Substantially the same means that the ratio of the difference between the length in the thickness direction and the length in the first direction to the length of the longer side is within 5%.

[0076] The length of the conductor part 12 in the thickness direction may be longer than the length of the conductor part 12 in the second direction, or may be the same as the length of the conductor part 12 in the second direction. Here, "same" is not limited to being strictly the same, but also includes being substantially the same. Substantially the same means that the ratio of the difference between the length in the thickness direction and the length in the second direction to the length of the longer side is within 5%.

[0077] The fillets 53 and 54 do not need to be formed on the solders 16 , 216 , and 316 .

[0078] The embodiments disclosed herein are to be considered in all respects as illustrative rather than restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope of the claims or within the scope equivalent to the claims. Description of Reference Numerals

[0079] 10: Wiring substrate 11: Substrate part 12: Conductor 13: Input section 14: Output section 15: Switch 16: Solder 20: Conductor layer 21: First wiring pattern (wiring pattern) 22: Second wiring pattern 23: Pad 23A: End 23B: End 23C: End 23D: End 30: Insulation layer 31: Substrate body 32: Insulation film 40: Base material 41: Plating 42: Opposite surface 43: Page 1 44: Page 1 45: Page 2 45A: Exposed face 46: Page 2 46A: Revealing the face 47: Top 51: Solder pin 52: Solder pin 53: Solder pin 54: Solder pin 90: Power supply department 91: Load 92: Wiring 93: Wiring 210: Wiring substrate 211: Substrate part 216: Solder 216A: 1st solder part 216B: Second solder part 216C: Solder section 3 223A: Pad 223B: pad part 230: Insulation layer 232: Insulation film 232A: Intermediate insulating film 310: Wiring substrate 311: Substrate Department 316: Solder 316A: 1st solder part 316B: Second solder part 316C: Solder section 3 320: Conductor layer 321A: Wiring pattern 321B: Wiring pattern 322: Insulation film 323A: pad part 323B: pad part 330: Insulation layer 332: Insulation film H1: Height H2: Height HC1: Height HC2: Height L1: Distance L2: Distance L3: Distance L4: Distance

Claims

1. A wiring substrate comprising a substrate portion and a conductor portion, The substrate portion includes a conductor layer and an insulating layer, the conductor layer has a wiring pattern, the insulating layer has an insulating film covering a portion of the wiring pattern, and a portion of the wiring pattern is configured as a pad portion not covered by the insulating film. The conductor portion is joined to the pad portion by solder, in, The conductor portion includes a conductive base material and a plating layer covering a portion of the base material. The substrate comprises: an opposing surface facing the pad portion on one side in the thickness direction of the substrate portion; a pair of first surfaces arranged on both sides of a first direction orthogonal to the thickness direction; and a pair of second surfaces arranged on both sides of a second direction orthogonal to the thickness direction and the first direction. The opposing surface and the pair of first surfaces are covered with the plating layer, The pair of second surfaces has an exposed surface where the substrate is not covered by the plating layer and is exposed, The plating layer covering the pair of first surfaces is bonded to the pad portion via the solder, The pair of second surfaces is arranged to overlap with the pad portion in the thickness direction.

2. The wiring substrate according to claim 1, wherein: A distance in the second direction from at least any one of the second surfaces to an end of the pad portion is shorter than a distance in the first direction from any one of the first surfaces to an end of the pad portion.

3. The wiring substrate according to claim 1 or claim 2, wherein: The conductor portion is arranged across the plurality of pad portions that are separated from each other, and is joined to each of the plurality of pad portions.

4. The wiring substrate according to claim 3, wherein: The solder is continuously arranged between the substrate portion and the opposing surface so as to straddle the plurality of separated land portions.

5. The wiring substrate according to claim 1 or claim 2, wherein: The entire facing surface of the conductor portion is provided so as to overlap with the pad portion.

6. The wiring substrate according to claim 1 or claim 2, wherein: The area of ​​each of the pair of first surfaces is larger than the area of ​​either of the pair of second surfaces.

7. The wiring substrate according to claim 1 or claim 2, wherein: The conductor part is formed in a long strip shape extending in the direction of current flow at a portion where the conductor part is joined.

8. The wiring substrate according to claim 1 or claim 2, wherein: A fillet of the solder joined to at least any one of the first surface and the land portion has a height from the land portion higher than a height from the land portion of a center position in the thickness direction of the first surface joined to the fillet.

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