Wiring circuit board

Abstract

To provide a wiring circuit board that allows for greater flexibility in wiring design. [Solution] The wiring circuit board 1 comprises a metal support substrate 11, an insulating layer 12 disposed on one side of the metal support substrate 11 in the thickness direction, and a conductor pattern 13 disposed on one side of the insulating layer 12 in the thickness direction. The conductor pattern 13 comprises wiring 131, and the wiring 131 includes a first wiring 131A, a second wiring 131B, and a third wiring 131C. The thickness T2 of the second wiring 131B is thicker than the thickness T1 of the first wiring 131A, and the thickness T3 of the third wiring 131C is thicker than the thickness T2 of the second wiring 131B.

Description

Technical Field

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[0001] The present invention relates to a wiring circuit board.

Background Art

[0002] Conventionally, a wiring circuit board including a plurality of wiring bodies arranged at intervals from each other is known (see, for example, Patent Document 1).

[0003] In the wiring circuit board of Patent Document 1, each of the plurality of wiring bodies has a conductor layer of the same thickness.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, in a wiring circuit board, it is required to increase the degree of freedom in wiring design by arranging wirings having different thicknesses according to the application.

[0006] An object of the present invention is to provide a wiring circuit board capable of increasing the degree of freedom in wiring design.

Means for Solving the Problems

[0007] The present invention [1] includes a metal support substrate, an insulating layer disposed on one surface in the thickness direction of the metal support substrate, and a conductor pattern disposed on one surface in the thickness direction of the insulating layer. The conductor pattern includes a wiring, and the wiring includes a first wiring, a second wiring, and a third wiring. A thickness T2 of the second wiring is thicker than a thickness T1 of the first wiring, and a thickness T3 of the third wiring is thicker than the thickness T2 of the second wiring. ​​The present invention [2] includes the wiring circuit board described in [1] above, wherein the third wiring has a central portion and an end portion in the thickness direction and in the width direction perpendicular to the direction in which the wiring extends, and the central portion protrudes toward one side in the thickness direction compared to the end portion.

[0009] The present invention [3] includes a wiring circuit board as described in [1] or [2] above, wherein the first wiring has a first conductor layer, the second wiring has a second conductor layer, and the third wiring has the first conductor layer and the second conductor layer covering the first conductor layer.

[0010] The present invention [4] includes a wiring circuit board according to any one of the above [1] to [3], wherein the conductor pattern further comprises terminals connected to the wiring.

[0011] The present invention [5] includes the wiring circuit board described in [4] above, wherein the thickness T4 of the terminal is thicker than the thickness T3 of the third wiring.

[0012] The present invention [6] includes a wiring circuit board according to [4] or [5] above, wherein the terminal has a first conductor layer and a second conductor layer disposed on one side in the thickness direction of the first conductor layer.

[0013] The present invention [7] includes a wiring circuit board according to any one of the above [4] to [6], wherein the wiring circuit board comprises a terminal arrangement portion on which the terminals are arranged, a wiring portion on which at least one selected from the group consisting of the first wiring, the second wiring, and the third wiring is arranged, and a connecting portion connecting the terminal arrangement portion and the wiring portion, wherein at least one selected from the group consisting of the first wiring, the second wiring, and the third wiring is arranged in the connecting portion.

[0014] The present invention [8] includes the wiring circuit board described in [7] above, wherein at least the third wiring is arranged in the connecting portion.

[0015] The present invention [9] includes a wiring circuit board as described in [7] or [8] above, wherein the wiring portion includes at least a first wiring portion on which the first wiring is arranged and a third wiring portion on which the third wiring is arranged, and the first wiring portion and the third wiring portion are spaced apart from each other in the thickness direction and in the width direction perpendicular to the direction in which the wiring extends. [Effects of the Invention]

[0016] The wiring circuit board of the present invention comprises a first wiring, a second wiring, and a third wiring, wherein the thickness T2 of the second wiring is greater than the thickness T1 of the first wiring, and the thickness T3 of the third wiring is greater than the thickness T2 of the second wiring. Therefore, the degree of freedom in wiring design can be increased. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 shows a plan view of a wiring circuit board as one embodiment of the present invention. [Figure 2] Figure 2 shows a rear view of a wiring circuit board as one embodiment of the present invention. [Figure 3] Figure 3 is a cross-sectional view AA of the wiring circuit board shown in Figure 1. [Figure 4] Figure 4 is a cross-sectional view of the circuit board (BB) of the wiring circuit board shown in Figure 1. [Figure 5] Figures 5A and 5B are process diagrams illustrating the manufacturing method of a wiring circuit board. Figure 5A shows the process of forming the insulating layer (base insulating layer), and Figure 5B shows the process of forming the first conductor layer. [Figure 6] Figures 6A and 6B, following Figure 5B, are process diagrams illustrating the manufacturing method of a wiring circuit board. Figure 6A shows the second conductor layer formation process, and Figure 6B shows the cover insulation layer formation process. [Figure 7] Figure 7 shows a plan view of a modified wiring circuit board. [Figure 8] Figure 8 is a cross-sectional view of the CC of the wiring circuit board of the modified example shown in Figure 7. [Modes for carrying out the invention]

[0018] 1. Wiring circuit board Referring to FIGS. 1 to 4, an embodiment of the wiring circuit board 1 will be described.

[0019] The wiring circuit board 1 includes a terminal arrangement portion 2 where terminals 132 and 133 are arranged, a wiring portion 3 where at least one selected from the group consisting of a first wiring 131A, a second wiring 131B, and a third wiring 131C is arranged, and a connecting portion 4 that connects the terminal arrangement portion 2 and the wiring portion 3. Specifically, as shown in FIG. 1, the wiring circuit board 1 includes a terminal arrangement portion 2A where terminals 132A, 132B, and 132C are arranged, a terminal arrangement portion 2B where terminals 133A, 133B, and 133C are arranged, a first wiring portion 3A where the first wiring 131A is arranged, a second wiring portion 3B where the second wiring  131B is arranged, a third wiring portion 3C where the third wiring 131C is arranged, a connecting portion 4A that connects the terminal arrangement portion 2A and the wiring portion 3, and a connecting portion 4B that connects the terminal arrangement portion 2B and the wiring portion 3.

[0020] The wiring circuit board 1 includes two terminal arrangement portions 2A and 2B. Terminals 132A, 132B, and 132C of the conductor pattern 13 described later are arranged in the terminal arrangement portion 2A. Terminals 133A, 133B, and 133C of the conductor pattern 13 described later are arranged in the terminal arrangement portion 2B.

[0021] The terminal arrangement portions 2A and 2B are arranged at intervals in the first direction. The first direction is the direction in which the wiring 131 (wiring portion 3) extends. The first direction (the direction in which the wiring 131 extends) is orthogonal to the thickness direction of the wiring circuit board 1. Each of the terminal arrangement portions 2A and 2B extends in the second direction. The second direction is the width direction of the wiring 131 (wiring portion 3). The second direction (width direction) is orthogonal to both the thickness direction and the first direction.

[0022] The wiring circuit board 1 comprises a plurality of wiring sections 3. Each wiring section 3 is provided with at least one selected from the group consisting of a first wiring 131A, a second wiring 131B, and a third wiring 131C of the conductor pattern 13, which will be described later. In other words, each wiring section 3 includes at least one selected from the group consisting of a first wiring section 3A on which the first wiring 131A is provided, a second wiring section 3B on which the second wiring 131B is provided, and a third wiring section 3C on which the third wiring 131C is provided. Preferably, each wiring section 3 includes at least a first wiring section 3A on which the first wiring 131A is provided and a third wiring section 3C on which the third wiring 131C is provided.

[0023] In the wiring circuit board 1 shown in Figure 1, the multiple wiring sections 3 include a first wiring section 3A, a second wiring section 3B, and a third wiring section 3C.

[0024] Each of the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C is positioned between the terminal arrangement section 2A and the terminal arrangement section 2B in the first direction. In this embodiment, each of the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C extends in the first direction. One end of each of the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C in the first direction is connected to the terminal arrangement section 2A via a connecting section 4A. The other end of each of the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C in the first direction is connected to the terminal arrangement section 2B via a connecting section 4B. The shapes of the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C are not limited and may be straight or curved.

[0025] The first wiring section 3A, the second wiring section 3B, and the third wiring section 3C are aligned along the second direction. In other words, the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C are aligned along the width direction perpendicular to the direction in which the wiring 131 extends. The first wiring section 3A, the second wiring section 3B, and the third wiring section 3C are spaced apart from each other in the second direction. In other words, the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C are spaced apart from each other in the width direction perpendicular to the direction in which the wiring 131 extends.

[0026] The order in which the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C are arranged in the second direction is not particularly limited. In Figure 1, the first wiring section 3A, the third wiring section 3C, and the second wiring section 3B are arranged in the second direction. That is, the first wiring section 3A and the third wiring section 3C are spaced apart from each other in the second direction, and the third wiring section 3C and the second wiring section 3B are spaced apart from each other in the second direction. In other words, the first wiring section 3A and the third wiring section 3C are spaced apart from each other in the width direction perpendicular to the direction in which the wiring 131 (wiring section 3) extends, and the third wiring section 3C and the second wiring section 3B are spaced apart from each other in the width direction perpendicular to the direction in which the wiring 131 (wiring section 3) extends.

[0027] The widths of the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C are, for example, 10 μm to 300 μm, preferably 50 μm to 250 μm. The widths of the first wiring section 3A, the second wiring section 3B, and the third wiring section 3C may be the same or different from each other.

[0028] Note that "width" refers to the maximum length in the width direction perpendicular to both the direction in which the wiring 131 (wiring section 3) extends and the thickness direction. For example, the "width" of the first wiring section 3A refers to the maximum length in the width direction perpendicular to both the direction in which the first wiring section 3A extends and the thickness direction. In this embodiment, "width" refers to the maximum length in the second direction.

[0029] In the second direction, the spacing between adjacent wiring sections 3 is, for example, 5 μm to 300 μm, preferably 10 μm to 250 μm. The spacing between adjacent wiring sections 3 may be the same or different.

[0030] In the second direction, the spacing between adjacent wiring sections 3 is, for example, the spacing between the first wiring section 3A and the third wiring section 3C, and the spacing between the third wiring section 3C and the second wiring section 3B.

[0031] The wiring circuit board 1 includes two connecting parts 4A and 4B.

[0032] The connecting section 4A is positioned between the terminal arrangement section 2A and the wiring section 3. The connecting section 4A connects the terminal arrangement section 2A and the wiring section 3.

[0033] The connecting section 4B is positioned between the terminal arrangement section 2B and the wiring section 3. The connecting section 4B connects the terminal arrangement section 2B and the wiring section 3.

[0034] The connecting parts 4A and 4B are arranged at a distance from each other in the first direction. Each of the connecting parts 4A and 4B extends in the second direction.

[0035] Each of the connecting sections 4A and 4B is provided with at least one selected from the group consisting of the first wiring 131A of the conductor pattern 13 (described later), the second wiring 131B of the conductor pattern 13 (described later), and the third wiring 131C of the conductor pattern 13 (described later).

[0036] In the wiring circuit board 1 shown in Figure 1, as will be described in more detail later, terminals 132A and 133A are connected by a single first wire 131A. Terminals 132B and 133B are connected by a single second wire 131B. Terminals 132C and 133C are connected by a composite wiring consisting of a second wire 131B and a third wire 131C.

[0037] In this embodiment, in each of the connecting sections 4A and 4B, the first wiring 131A is arranged between the terminal arrangement sections 2A and 2B and the first wiring section 3A. In other words, a single first wiring 131A is arranged continuously between terminals 132A and 133A, connecting terminals 132A and 133A in the connecting section 4A, the first wiring section 3A, and the connecting section 4B.

[0038] In this embodiment, in each of the connecting sections 4A and 4B, a second wire 131B is arranged between the terminal arrangement sections 2A and 2B and the second wiring section 3B. In other words, a single second wire 131B is arranged continuously between terminals 132B and 133B, connecting terminals 132B and 133B.

[0039] In this embodiment, in each of the connecting sections 4A and 4B, the second wiring 131B is arranged between the terminal arrangement sections 2A and 2B and the third wiring section 3C. That is, a composite wiring consisting of the second wiring 131B and the third wiring 131C is arranged continuously in the connecting section 4A, the third wiring section 3C, and the connecting section 4B between terminals 132C and 133C, connecting terminals 132C and 133C. The composite wiring consists of the second wiring 131B arranged in the connecting section 4A, the third wiring 131C arranged in the third wiring section 3C, and the second wiring 131B arranged in the connecting section 4B. In the composite wiring, the second wiring 131B and the third wiring 131C are electrically connected, as will be described in more detail later, with the second conductor layer 1312 of the second wiring 131B and the second conductor layer 1312 of the third wiring 131C being continuous.

[0040] In other words, in this embodiment, the first wiring 131A and the second wiring 131B are arranged in the connecting portions 4A and 4B respectively, but the third wiring 131C is not arranged.

[0041] As shown in Figures 3 and 4, the wiring circuit board 1 comprises a metal support substrate 11, an insulating layer 12 (base insulating layer), and a conductor pattern 13. The wiring circuit board 1 also optionally comprises a cover insulating layer 14.

[0042] (1) Metal support substrate The metal support substrate 11 supports the insulating layer 12, the conductor pattern 13, and the cover insulating layer 14. The metal support substrate 11 is made of metal. Examples of materials for the metal support substrate 11 include copper, nickel, cobalt, iron, and alloys thereof. Examples of alloys include copper alloys. Preferably, copper alloys are used as the material for the metal support substrate 11.

[0043] The thickness of the metal support substrate 11 is, for example, 10 μm to 300 μm, preferably 50 μm to 250 μm.

[0044] As shown in Figures 1 and 3, the metal support substrate 11 has two terminal support portions 111A and 111B and a plurality of wiring support portions 112A, 112B, and 112C.

[0045] The terminal support portion 111A is a metal support substrate 11 for the terminal arrangement portion 2A and the connecting portion 4A. The terminal support portion 111A supports the terminals 132A, 132B, and 132C of the conductor pattern 13 arranged in the terminal arrangement portion 2A, and at least one of the first wiring 131A, the second wiring 131B, and the third wiring 131C of the conductor pattern 13 arranged in the connecting portion 4A.

[0046] The terminal support portion 111B is a metal support substrate 11 for the terminal arrangement portion 2B and the connecting portion 4B. The terminal support portion 111B is positioned at a distance from the terminal support portion 111A in the first direction. The terminal support portion 111B supports the terminals 133A, 133B, and 133C of the conductor pattern 13 arranged in the terminal arrangement portion 2B, and at least one of the first wiring 131A, the second wiring 131B, and the third wiring 131C of the conductor pattern 13 arranged in the connecting portion 4B.

[0047] The wiring support portion 112A is the metal support substrate 11 of the first wiring portion 3A. The wiring support portion 112A is positioned between the terminal support portion 111A and the terminal support portion 111B in the first direction. The wiring support portion 112A supports the first wiring 131A. The wiring support portion 112A extends in the first direction along the first wiring 131A. One end of the wiring support portion 112A in the first direction is connected to the terminal support portion 111A. The other end of the wiring support portion 112A in the first direction is connected to the terminal support portion 111B.

[0048] The wiring support portion 112B is the metal support substrate 11 of the second wiring portion 3B. The wiring support portion 112B is positioned between the terminal support portion 111A and the terminal support portion 111B in the first direction. The wiring support portion 112B supports the second wiring 131B. The wiring support portion 112B extends in the first direction along the second wiring 131B. One end of the wiring support portion 112B in the first direction is connected to the terminal support portion 111A. The other end of the wiring support portion 112B in the first direction is connected to the terminal support portion 111B.

[0049] The wiring support portion 112C is the metal support substrate 11 of the third wiring portion 3C. The wiring support portion 112C is positioned between the terminal support portion 111A and the terminal support portion 111B in the first direction. The wiring support portion 112C supports the third wiring 131C. The wiring support portion 112C extends in the first direction along the third wiring 131C. One end of the wiring support portion 112C in the first direction is connected to the terminal support portion 111A. The other end of the wiring support portion 112C in the first direction is connected to the terminal support portion 111B.

[0050] The wiring support sections 112A, 112B, and 112C are aligned along the second direction. The wiring support sections 112A, 112B, and 112C are spaced apart from each other in the second direction.

[0051] The width of the wiring support portion 112A is, for example, 5 μm to 300 μm, preferably 10 μm to 250 μm. The width of the wiring support portion 112A may be the same as or different from the width of the first wiring portion 3A.

[0052] The ratio of the thickness of the wiring support portion 112A to its width (thickness / width) is, for example, 2 or more, preferably 5 or more, and also, for example, 30 or less, preferably 10 or less. Hereinafter, the ratio of the thickness of the wiring support portion to its width (thickness / width) is defined as the aspect ratio of the wiring support portion.

[0053] If the aspect ratio of the wiring support portion 112A is greater than or equal to the above lower limit, the first wiring portion 3A can be easily deformed in the width direction compared to the thickness direction. Furthermore, the rigidity of the first wiring portion 3A in the thickness direction can be ensured.

[0054] The width and aspect ratio of the wiring support section 112B and the wiring support section 112C are also adjusted as appropriate within the range described above for the width and aspect ratio of the wiring support section 112A.

[0055] In other words, if the aspect ratio of the wiring support portion 112B is greater than or equal to the lower limit value, the second wiring portion 3B can be easily deformed in the width direction compared to the thickness direction. Furthermore, the rigidity of the second wiring portion 3B in the thickness direction can be ensured. Moreover, if the aspect ratio of the wiring support portion 112C is greater than or equal to the lower limit value, the third wiring portion 3C can be easily deformed in the width direction compared to the thickness direction. Furthermore, the rigidity of the third wiring portion 3C in the thickness direction can be ensured.

[0056] The widths and aspect ratios of the wiring support sections 112A, 112B, and 112C may be the same or different from each other.

[0057] In the second direction, the distance between wiring support portion 112A and wiring support portion 112C, and the distance between wiring support portion 112C and wiring support portion 112B are, for example, 5 μm to 300 μm, preferably 10 μm to 250 μm. In the second direction, the distance between wiring support portion 112A and wiring support portion 112C, and the distance between wiring support portion 112C and wiring support portion 112B may be the same or different.

[0058] (2) Insulating layer As shown in Figures 3 and 4, the insulating layer 12 (base insulating layer) is positioned on one side of the metal support substrate 11 in the thickness direction. In other words, the insulating layer 12 is in contact with one side of the metal support substrate 11 in the thickness direction. The insulating layer 12 is positioned between the metal support substrate 11 and the conductor pattern 13 in the thickness direction. The insulating layer 12 insulates the metal support substrate 11 from the conductor pattern 13. The insulating layer 12 is made of a resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester. Polyimide is preferred.

[0059] The thickness of the insulating layer 12 is, for example, 1 μm or more, preferably 5 μm or more, and also, for example, 100 μm or less, preferably 50 μm or less.

[0060] (3) Conductor pattern As shown in Figures 3 and 4, the conductor pattern 13 is positioned on one side in the thickness direction of the insulating layer 12 (base insulating layer). In other words, the conductor pattern 13 is in contact with one side in the thickness direction of the insulating layer 12. In the thickness direction, the conductor pattern 13 is positioned on the side opposite the metal support substrate 11 to the insulating layer 12. The shape of the conductor pattern 13 is not limited.

[0061] The conductor pattern 13 comprises a plurality of wires 131. Preferably, the conductor pattern 13 further comprises a plurality of terminals 132, 133 connected to the wires 131.

[0062] Multiple terminals 132A, 132B, and 132C are arranged in the terminal arrangement section 2A. Multiple terminals 132A, 132B, and 132C are arranged along the second direction. Multiple terminals 132A, 132B, and 132C are spaced apart from each other in the second direction.

[0063] Multiple terminals 133A, 133B, and 133C are arranged in the terminal arrangement section 2B. Multiple terminals 133A, 133B, and 133C are arranged along the second direction. Multiple terminals 133A, 133B, and 133C are spaced apart from each other in the second direction.

[0064] Each of the multiple terminals 132 and 133 has a square land shape.

[0065] Wiring 131 includes a first wiring 131A, a second wiring 131B, and a third wiring 131C. Examples of wiring 131 include signal wiring (e.g., differential wiring), power wiring, ground wire, and antenna wire.

[0066] The first wiring 131A, the second wiring 131B, and the third wiring 131C each have different thicknesses, as will be explained in more detail later. Therefore, the appropriate wiring can be selected depending on the function and location of the wiring.

[0067] At least a portion of the first wiring 131A is arranged in the first wiring section 3A. In this embodiment, the first wiring 131A is arranged continuously in the connecting section 4A, the first wiring section 3A, and the connecting section 4B, and electrically connects terminal 132A and terminal 133A. One end of the first wiring 131A in the first direction is connected to terminal 132A. The other end of the first wiring 131A in the first direction is connected to terminal 133A.

[0068] As shown in Figure 1, in this embodiment, two first wirings 131A are arranged in the connecting sections 4A and 4B and the first wiring section 3A. The first wirings 131A are, for example, signal wiring (for example, differential wiring).

[0069] At least a portion of the second wiring 131B is arranged in the second wiring section 3B. In this embodiment, the second wiring 131B is arranged continuously in the connecting section 4A, the second wiring section 3B, and the connecting section 4B, and electrically connects terminals 132B and 133B. One end of the second wiring 131B in the first direction is connected to terminal 132B. The other end of the second wiring 131B in the first direction is connected to terminal 133B.

[0070] As shown in Figure 1, in this embodiment, one second wire 131B is arranged in the connecting sections 4A and 4B and the second wiring section 3B. The second wire 131B is, for example, a power supply wire.

[0071] At least a portion of the third wiring 131C is located in the third wiring section 3C. In this embodiment, the third wiring 131C is located in the third wiring section 3C and, together with the second wiring 131B located in the connecting sections 4A and 4B, forms a composite wiring. The composite wiring consisting of the second wiring 131B and the third wiring 131C electrically connects terminal 132C and terminal 133C. One end of the composite wiring in the first direction is connected to terminal 132C. The other end of the composite wiring in the first direction is connected to terminal 133C.

[0072] As shown in Figure 1, in this embodiment, a composite wiring consisting of a second wiring 131B and a third wiring 131C is arranged in the connecting sections 4A and 4B and the third wiring section 3C. The composite wiring consisting of the second wiring 131B and the third wiring 131C is, for example, a power supply wiring.

[0073] The first wiring 131A, the second wiring 131B, and the third wiring 131C (a composite wiring consisting of the second wiring 131B and the third wiring 131C) are aligned along the second direction. The first wiring 131A, the second wiring 131B, and the third wiring 131C are spaced apart from each other in the second direction.

[0074] (6) Cover insulation layer The cover insulating layer 14 covers all the wiring 131 in the wiring section 3. Specifically, as shown in Figure 1, the cover insulating layer 14 covers the first wiring 131A located in the first wiring section 3A, the second wiring 131B located in the second wiring section 3B, and the third wiring 131C located in the third wiring section 3C. In addition, the cover insulating layer 14 may cover at least a portion of the first wiring 131A, the second wiring 131B, and the third wiring 131C located in the connecting sections 4A and 4B.

[0075] As shown in Figures 1 and 4, the cover insulating layer 14 does not cover terminals 132 and 133. Furthermore, the cover insulating layer 14 does not need to cover at least a portion of the first wiring 131A, second wiring 131B, and third wiring 131C located in the connecting portions 4A and 4B.

[0076] The cover insulating layer 14 is positioned on one side in the thickness direction of the insulating layer 12 (base insulating layer). The cover insulating layer 14 is made of resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester. Polyimide is preferred.

[0077] 2. Wiring and terminal details Referring to Figure 3, the details of the first wiring 131A, the second wiring 131B, the third wiring 131C, and terminals 132 and 133 will be described.

[0078] (1) First wiring As shown in Figure 3, the first wiring 131A has a roughly rectangular shape in cross-section. One side of the first wiring 131A in the thickness direction is flat. Both sides of the first wiring 131A in the width direction are planes extending in the thickness direction.

[0079] Furthermore, "one side of the first wiring 131A in the thickness direction is flat" means that the difference between the maximum and minimum thickness of the first wiring 131A itself is 5% or less of the maximum thickness. In other words, unavoidable surface irregularities that occur during the manufacturing process are acceptable.

[0080] The thickness T1 of the first wiring 131A is thinner than the thickness T2 of the second wiring 131B, which will be described later. Also, the thickness T1 of the first wiring 131A is thinner than the thickness T3 of the third wiring 131C, which will be described later. Furthermore, the thickness T1 of the first wiring 131A is thinner than the thickness T4 of terminals 132 and 133, which will be described later. In other words, the thickness T1 of the first wiring 131A is the thinnest among the thickness T1 of the first wiring 131A, the thickness T2 of the second wiring 131B, the thickness T3 of the third wiring 131C, and the thickness T4 of terminals 132 and 133.

[0081] Note that the thickness T1 of the first wiring 131A, the thickness T2 of the second wiring 131B, the thickness T3 of the third wiring 131C, and the thickness T4 of terminals 132 and 133 represent the maximum length from one side in the thickness direction to the other side in the thickness direction.

[0082] The thickness T1 of the first wiring 131A is, for example, 1 μm or more, preferably 5 μm or more, and for example, 50 μm or less, preferably 30 μm or less.

[0083] The width of the first wiring 131A is, for example, 1 μm or more, preferably 5 μm or more, and also, for example, 50 μm or less, preferably 30 μm or less. The width of the first wiring 131A is preferably smaller than the width of the second wiring 131B described later, and also smaller than the width of the third wiring 131C described later.

[0084] The first wiring 131A has a first conductor layer 1311. The first wiring 131A does not have a second conductor layer 1312. In this embodiment, the first wiring 131A consists of a seed layer (not shown) and the first conductor layer 1311, which will be described later.

[0085] The first conductor layer 1311 of the first wiring 131A is made of metal. Examples of metals include copper, silver, gold, iron, aluminum, chromium, and alloys thereof. To obtain good electrical properties, copper is preferably used as the metal.

[0086] The first conductor layer 1311 of the first wiring 131A is positioned on one side in the thickness direction of the insulating layer 12. In this embodiment, the first conductor layer 1311 of the first wiring 131A is connected to terminals 132A and 133A. Specifically, the first conductor layer 1311 of the first wiring 131A is preferably continuous with the first conductor layer 1321 of terminal 132A and the first conductor layer 1321 of terminal 133A, which will be described later. In other words, the first conductor layer 1311 of the first wiring 131A is preferably made from the same metal as the first conductor layer 1321 of terminal 132A and the first conductor layer 1321 of terminal 133A, which will be described later.

[0087] (2)Second wiring As shown in Figure 3, the second wiring 131B has a roughly rectangular shape in cross-section. One side of the second wiring 131B in the thickness direction is flat. Both sides of the second wiring 131B in the width direction are planes extending in the thickness direction.

[0088] Furthermore, "one side of the second wiring 131B in the thickness direction is flat" means that the difference between the maximum and minimum thickness of the second wiring 131B itself is 5% or less of the maximum thickness. In other words, unavoidable surface irregularities that occur during the manufacturing process are acceptable.

[0089] The thickness T2 of the second wiring 131B is greater than the thickness T1 of the first wiring 131A. Also, the thickness T2 of the second wiring 131B is less than the thickness T3 of the third wiring 131C, which will be described later. Furthermore, the thickness T2 of the second wiring 131B is less than the thickness T4 of terminals 132 and 133, which will be described later.

[0090] The thickness T2 of the second wiring 131B is, for example, 5 μm or more, preferably 10 μm or more, and for example, 100 μm or less, preferably 50 μm or less.

[0091] The difference (T2-T1) between the thickness T2 of the second wiring 131B and the thickness T1 of the first wiring 131A is, for example, 3 μm or more, preferably 5 μm or more, and also, for example, 50 μm or less, preferably 30 μm or less.

[0092] The width of the second wiring 131B is, for example, 5 μm or more, preferably 10 μm or more, and also, for example, 100 μm or less, preferably 50 μm or less. The width of the second wiring 131B is preferably greater than the width of the first wiring 131A, and smaller than the width of the third wiring 131C, which will be described later.

[0093] The second wiring 131B has a second conductor layer 1312. The second wiring 131B does not have a first conductor layer 1311. In this embodiment, the second wiring 131B consists of a seed layer (not shown) and a second conductor layer 1312, which will be described later.

[0094] The second conductor layer 1312 of the second wiring 131B is made of metal. Examples of metals include copper, silver, gold, iron, aluminum, chromium, and alloys thereof. To obtain good electrical properties, copper is preferably used as the metal.

[0095] The second conductor layer 1312 of the second wiring 131B is positioned on one side in the thickness direction of the insulating layer 12. In this embodiment, the second conductor layer 1312 of the second wiring 131B is connected to terminals 132B and 133B. Specifically, the second conductor layer 1312 of the second wiring 131B is preferably continuous with the second conductor layer 1322 of terminal 132B and the second conductor layer 1322 of terminal 133B, which will be described later. In other words, the second conductor layer 1312 of the second wiring 131B is preferably made from the same metal as the second conductor layer 1322 of terminal 133A and the second conductor layer 1322 of terminal 133B, which will be described later.

[0096] (3)Third wiring As shown in Figure 3, the third wiring 131C has an arch shape (inverted U-shape in cross-section) in cross-sectional view. The third wiring 131C has a central part (center in the width direction) and an end (end in the width direction) in the width direction. The central part is located in the center of the third wiring 131C in the width direction. The end is located at the end of the third wiring 131C in the width direction. In the width direction, the central part protrudes toward one side in the thickness direction compared to the end. In other words, in the width direction, the central part protrudes toward the opposite side of the metal support substrate 11 relative to the insulating layer 12 in the thickness direction compared to the end. One side of the third wiring 131C in the thickness direction has a substantially arc shape. Both sides of the third wiring 131C in the width direction are planes extending in the thickness direction.

[0097] If the widthwise central portion of the third wiring 131C protrudes toward one side in the thickness direction compared to the widthwise end portion of the third wiring 131C, the rigidity of the third wiring 131C in the thickness direction can be increased while suppressing the increase in rigidity of the third wiring 131C in the width direction. As a result, the rigidity of the third wiring portion 3C in the thickness direction can be increased without hindering the deformation of the third wiring portion 3C in the width direction.

[0098] The percentage difference between the thickness of the widthwise central portion of the third wiring 131C and the thickness of the widthwise end portion of the third wiring 131C ((difference between the thickness of the central portion and the thickness of the end portion) / thickness of the central portion × 100) is, for example, 10% or more, preferably 20% or more, more preferably 25% or more, and also, for example, 70% or less, preferably 60% or less, more preferably 55% or less. The percentage difference between the thickness of the widthwise central portion of the third wiring 131C and the thickness of the widthwise end portion of the third wiring 131C ((difference between the thickness of the central portion and the thickness of the end portion) / thickness of the central portion × 100) is defined as the protrusion ratio of the widthwise central portion of the third wiring 131C.

[0099] If the protrusion ratio of the center of the third wiring 131C in the width direction is greater than or equal to the above lower limit, the rigidity of the wiring in the thickness direction can be reliably increased. If the protrusion ratio of the center of the third wiring 131C in the width direction is less than or equal to the above upper limit, the wiring cross-sectional area can be secured, and the electrical resistance of the third wiring 131C can be reduced.

[0100] The thickness T3 of the third wiring 131C is greater than the thickness T1 of the first wiring 131A. Also, the thickness T3 of the third wiring 131C is greater than the thickness T2 of the second wiring 131B. Furthermore, the thickness T3 of the third wiring 131C is thinner than the thickness T4 of terminals 132 and 133, which will be described later.

[0101] As described above, the thickness T3 of the third wiring 131C is the maximum length from one side in the thickness direction to the other side in the thickness direction of the third wiring 131C. In other words, the thickness T3 of the third wiring 131C is the thickness of the third wiring 131C at the center in the width direction.

[0102] The thickness T3 of the third wiring 131C is, for example, 10 μm or more, preferably 30 μm or more, and for example, 150 μm or less, preferably 100 μm or less.

[0103] The difference (T3-T1) between the thickness T3 of the third wiring 131C and the thickness T1 of the first wiring 131A is, for example, 5 μm or more, preferably 10 μm or more, and for example, 100 μm or less, preferably 50 μm or less.

[0104] The difference (T3-T2) between the thickness T3 of the third wiring 131C and the thickness T2 of the second wiring 131B is, for example, 5 μm or more, preferably 10 μm or more, and for example, 50 μm or less, preferably 30 μm or less.

[0105] The ratio of the thickness T3 of the third wiring 131C to the width of the third wiring 131C (thickness / width) is, for example, 3.0 or less, preferably 2.0 or less, more preferably 1.7 or less, and more preferably 1.3 or less. Hereinafter, the ratio of the thickness T2 of the third wiring 131C to the width of the third wiring 131C (thickness / width) is defined as the aspect ratio of the third wiring 131C.

[0106] If the aspect ratio of the third wiring 131C is below the above upper limit, it is possible to suppress an excessive increase in the rigidity of the third wiring 131C in the thickness direction.

[0107] The aspect ratio of the third wiring 131C is, for example, 0.1 or more, preferably 0.3 or more, more preferably 0.5 or more, and more preferably 0.8 or more.

[0108] The width of the third wiring 131C is appropriately adjusted within a range that satisfies the aspect ratio of the third wiring 131C described above. Preferably, the width of the third wiring 131C is greater than the width of the first wiring 131A and greater than the width of the second wiring 131B. The width of the third wiring 131C is, for example, 10 μm or more, preferably 30 μm or more, and also, for example, 300 μm or less, preferably 200 μm or less. Furthermore, the wiring cross-sectional area of ​​the third wiring 131C is preferably greater than the wiring cross-sectional area of ​​the first wiring 131A and greater than the wiring cross-sectional area of ​​the second wiring 131B. Since the wiring circuit board 1 is equipped with a third wiring 131C with a relatively large wiring cross-sectional area, electrical resistance can be reduced.

[0109] The third wiring 131C has a first conductor layer 1311 and a second conductor layer 1312 covering the first conductor layer 1311. In this embodiment, the third wiring 131C consists of a seed layer (not shown), a first conductor layer 1311, and a second conductor layer 1312 covering the first conductor layer 1311.

[0110] The first conductor layer 1311 of the third wiring 131C is made from the same metal as the first conductor layer 1311 of the first wiring 131A described above.

[0111] The first conductor layer 1311 of the third wiring 131C is positioned on one side in the thickness direction of the insulating layer 12. The first conductor layer 1311 of the third wiring 131C is positioned in the center in the width direction of the third wiring 131C. The first conductor layer 1311 of the third wiring 131C has a substantially rectangular shape in cross-section.

[0112] The width of the first conductor layer 1311 of the third wiring 131C is smaller than the width (total width) of the third wiring 131C. The width of the first conductor layer 1311 of the third wiring 131C is, for example, 1 μm or more, preferably 5 μm or more, and also, for example, 50 μm or less, preferably 30 μm or less.

[0113] The thickness of the first conductor layer 1311 of the third wiring 131C is thinner than the thickness T3 of the third wiring 131C. The thickness of the first conductor layer 1311 of the third wiring 131C is, for example, 1 μm or more, preferably 5 μm or more, and also, for example, 50 μm or less, preferably 30 μm or less.

[0114] The second conductor layer 1312 of the third wiring 131C is made from the same metal as the second conductor layer 1312 of the second wiring 131B described above.

[0115] The second conductor layer 1312 of the third wiring 131C is positioned on one side in the thickness direction of the insulating layer 12 and covers one side in the thickness direction and both sides in the width direction of the first conductor layer 1311 of the third wiring 131C. The second conductor layer 1312 of the third wiring 131C forms one side in the thickness direction and both sides in the width direction of the third wiring 131C.

[0116] The width of the second conductor layer 1312 of the third wiring 131C is the same as the width (total width) of the third wiring 131C. Also, the width of the second conductor layer 1312 of the third wiring 131C is greater than the width of the first conductor layer 1311 of the third wiring 131C. The width of the second conductor layer 1312 of the third wiring 131C is, for example, 3 μm or more, preferably 10 μm or more, and also, for example, 100 μm or less, preferably 75 μm or less.

[0117] The thickness of the second conductor layer 1312 of the third wiring 131C is thinner than the thickness T3 of the third wiring 131C. The thickness of the second conductor layer 1312 of the third wiring 131C is, for example, 5 μm or more, preferably 10 μm or more, and also, for example, 100 μm or less, preferably 50 μm or less.

[0118] Furthermore, the thickness of the second conductor layer 1312 of the third wiring 131C is the difference between the length from one side in the thickness direction of the third wiring 131C to the other side in the thickness direction and the thickness of the first conductor layer 1311 of the third wiring 131C in the portion where the first conductor layer 1311 of the third wiring 131C exists, and the length from one side in the thickness direction of the third wiring 131C to the other side in the thickness direction in the portion where the first conductor layer 1311 of the third wiring 131C does not exist.

[0119] The thickness ratio of the second conductor layer 1312 to the first conductor layer 1311 in the widthwise central portion of the third wiring 131C is, for example, 1 or more, preferably 2 or more, and for example, 10 or less, preferably 5 or less.

[0120] In this embodiment, as shown in Figures 1 and 4, a composite wiring consisting of a second wiring 131B and a third wiring 131C connects terminals 132C and 133C. In the composite wiring, the second conductor layer 1312 of the third wiring 131C is continuous with the second conductor layer of the second wiring 131B. The second conductor layer 1312 of the composite wiring (the second conductor layer 1312 that is continuous in the second wiring 131B and the third wiring 131C) is continuous with the second conductor layer 1322 of terminal 132C and the second conductor layer 1322 of terminal 133C, which will be described later. In this embodiment, the first conductor layer 1311 of the third wiring 131C is not continuous with the first conductor layer 1321 of terminal 132C and the first conductor layer 1321 of terminal 133C, which will be described later. The first conductor layer 1311 of the third wiring 131C is preferably made from the same metal as the first conductor layer 1321 of terminal 132C and the first conductor layer 1321 of terminal 133C, which will be described later, and the second conductor layer 1312 of the third wiring 131C is preferably made from the same metal as the second conductor layer 1322 of terminal 132C and the second conductor layer 1322 of terminal 133C, which will be described later.

[0121] (4) Terminals The cross-sectional shape (not shown) of terminals 132 (132A, 132B, 132C) and 133 (133A, 133B, 133C) is not particularly limited as long as it has a first conductor layer 1321 (described later) and a second conductor layer 1322 arranged on one side in the thickness direction of the first conductor layer 1321. For example, if the width of the first conductor layer 1321 and the width of the second conductor layer 1322 of terminals 132 and 133 (described later) are the same, the cross-sectional shape of terminals 132 and 133 is approximately rectangular, and if the width of the first conductor layer 1321 of terminals 132 and 133 (described later) is greater than the width of the second conductor layer 1322, the shape is approximately convex (a shape in which an approximately rectangular second conductor layer 1322 is laminated on one side in the thickness direction of an approximately rectangular first conductor layer 1321).

[0122] The thickness T4 of terminals 132 and 133 is greater than the thickness T1 of the first wiring 131A. Also, the thickness T4 of terminal 132 is greater than the thickness T2 of the second wiring 131B. Furthermore, the thickness T4 of terminals 132 and 133 is greater than the thickness T3 of the third wiring 131C. In other words, the thickness T4 of terminals 132 and 133 is the thickest among the thickness T1 of the first wiring 131A, the thickness T2 of the second wiring 131B, the thickness T3 of the third wiring 131C, and the thickness T4 of terminals 132 and 133.

[0123] The thickness T4 of terminals 132 and 133 is, for example, 15 μm or more, preferably 40 μm or more, and also, for example, 500 μm or less, preferably 300 μm or less. Note that the thickness T4 of terminals 132 and 133 is the total thickness of the first conductor layer 1321 of terminals 132 and 133 and the second conductor layer 1322 of terminal 132, which will be described later. Note that terminals 132A, 132B, 132C, 133A, 133B, and 133C each have the same thickness.

[0124] The difference (T4-T1) between the thickness T4 of terminals 132 and 133 and the thickness T1 of the first wiring 131A is, for example, 5 μm or more, preferably 10 μm or more, and also, for example, 100 μm or less, preferably 50 μm or less. The difference (T4-T1) between the thickness T4 of terminals 132 and 133 and the thickness T1 of the first wiring 131A is the same as the thickness of the second conductor layer 1322 of terminals 132 and 133, which will be described later.

[0125] The difference (T4-T2) between the thickness T4 of terminals 132 and 133 and the thickness T2 of the second wiring 131B is, for example, 1 μm or more, preferably 5 μm or more, and also, for example, 50 μm or less, preferably 30 μm or less. The difference (T4-T2) between the thickness T4 of terminals 132 and 133 and the thickness T2 of the second wiring 131B is the same as the thickness of the first conductor layer 1321 of terminals 132 and 133, which will be described later.

[0126] The difference (T4-T3) between the thickness T4 of terminals 132 and 133 and the thickness T3 of the third wiring 131C is, for example, 1 μm or more, preferably 5 μm or more, and for example, 50 μm or less, preferably 30 μm or less.

[0127] The width of terminals 132 and 133 is, for example, 15 μm or more, preferably 40 μm or more, and also, for example, 500 μm or less, preferably 300 μm or less. The width of terminals 132 and 133 is preferably greater than the width of the first wiring 131A, greater than the width of the second wiring 131B, and greater than the width of the third wiring 131C. Note that the width of terminals 132 and 133 indicates the maximum length in the width direction.

[0128] Each of the terminals 132 and 133 has a first conductor layer 1321 and a second conductor layer 1322 arranged on one side of the first conductor layer 1321 in the thickness direction. In this embodiment, terminals 132 and 133 consist of a seed layer (not shown), a first conductor layer 1311, and a second conductor layer 1312 arranged on one side of the first conductor layer 1311 in the thickness direction.

[0129] The first conductor layer 1321 of terminals 132 and 133 is made of the same metal as the first conductor layer 1311 of the first wiring 131A and the first conductor layer 1311 of the third wiring 131C.

[0130] The first conductor layer 1321 of terminals 132 and 133 is positioned on one side in the thickness direction of the insulating layer 12. The first conductor layer 1321 of terminals 132 and 133 has a substantially rectangular shape in cross-section.

[0131] The width of the first conductor layer 1321 of terminals 132 and 133 is the same as the width (total width) of terminals 132 and 133. The width of the first conductor layer 1321 of terminals 132 and 133 is, for example, 15 μm or more, preferably 40 μm or more, and also, for example, 500 μm or less, preferably 300 μm or less.

[0132] The thickness of the first conductor layer 1321 of terminals 132 and 133 is thinner than the thickness T4 of terminals 132 and 133. The thickness of the first conductor layer 1321 of terminals 132 and 133 is, for example, 1 μm or more, preferably 5 μm or more, and also, for example, 50 μm or less, preferably 30 μm or less.

[0133] The second conductor layer 1322 of terminals 132 and 133 is made of the same metal as the second conductor layer 1312 of the second wiring 131B and the second conductor layer 1312 of the third wiring 131C.

[0134] The second conductor layer 1322 of terminals 132 and 133 is positioned on one side in the thickness direction of the first conductor layer 1321 of terminals 132 and 133. In other words, the second conductor layer 1322 of terminals 132 and 133 is in contact with one side in the thickness direction of the first conductor layer 1321 of terminals 132 and 133.

[0135] The width of the second conductor layer 1322 of terminals 132 and 133 may be the same as the width (total width) of terminals 132 and 133, or it may be smaller than the width (total width) of terminals 132 and 133. Preferably, it is smaller than the width (total width) of terminals 132 and 133. The width of the second conductor layer 1322 of terminals 132 and 133 is, for example, 5 μm or more, preferably 10 μm or more, and also, for example, 100 μm or less, preferably 50 μm or less.

[0136] The thickness of the second conductor layer 1322 of terminals 132 and 133 is thinner than the thickness T4 of terminals 132 and 133. The thickness of the second conductor layer 1322 of terminals 132 and 133 is, for example, 5 μm or more, preferably 10 μm or more, and also, for example, 100 μm or less, preferably 50 μm or less.

[0137] 3. Manufacturing method of a wiring circuit board Next, the manufacturing method of the wiring circuit board 1 will be described with reference to Figures 5A to 6B.

[0138] The manufacturing method for the wiring circuit board 1 includes an insulating layer formation step (see Figure 5A), a first conductor layer formation step (see Figure 5B), a second conductor layer formation step (see Figure 6A), a cover insulating layer formation step (see Figure 6B), and an etching step (not shown).

[0139] (1) Insulating layer formation process (base insulating layer formation process) As shown in Figure 5A, in the insulating layer formation process, an insulating layer 12 (base insulating layer) is formed on one side in the thickness direction of the metal support substrate 11. Specifically, a roll of metal foil M is prepared as the material for the metal support substrate 11. Next, a photosensitive resin solution (varnish) is applied to the metal foil M drawn from the roll and dried. By drying, a photosensitive resin coating film is formed on the metal foil M. Next, the photosensitive resin coating film is exposed to light. Alternatively, the insulating layer 12 may be formed on the metal foil M in a predetermined pattern by exposing and developing a portion of the photosensitive resin.

[0140] (2) First conductor layer formation process Next, as shown in Figure 5B, in the first conductor layer formation step, the first conductor layers 1311 for the first wiring 131A and the third wiring 131C, and the first conductor layers 1321 for the terminals 132 and 133 (see Figure 1) are formed on one side in the thickness direction of the insulating layer 12.

[0141] In detail, first, a seed layer (not shown) is formed on one side in the thickness direction of the insulating layer 12. The seed layer is formed, for example, by sputtering. Examples of materials for the seed layer include chromium, copper, nickel, titanium, and alloys thereof. If the insulating layer 12 is formed in a predetermined pattern, the seed layer may be formed on one side in the thickness direction of both the insulating layer 12 and the metal foil M.

[0142] Next, a plating resist R1 is bonded to one side in the thickness direction of the seed layer, and the plating resist R1 is exposed while shielding the areas where the first conductor layers 1311 of the first wiring 131A and the third wiring 131C, and the first conductor layers 1321 of the terminals 132 and 133 are formed.

[0143] Next, the exposed plating resist R1 is developed. This removes the plating resist R1 from the light-shielded areas, exposing the seed layer in the areas where the first conductor layers 1311 of the first wiring 131A and the third wiring 131C, and the first conductor layers 1321 of the terminals 132 and 133 are formed. Meanwhile, the plating resist R1 in the exposed areas remains.

[0144] Next, the first conductor layers 1311 of the first wiring 131A and the third wiring 131C, and the first conductor layers 1321 of the terminals 132 and 133 are formed on the exposed seed layer by electroplating.

[0145] After forming the first conductor layers 1311 of the first wiring 131A and the third wiring 131C, and the first conductor layers 1321 of the terminals 132 and 133, the plating resist R1 is peeled off.

[0146] (3) Second conductor layer formation process Next, as shown in Figure 6A, in the second conductor layer formation step, the second conductor layer 1312 of the second wiring 131B is formed on one side in the thickness direction of the insulating layer 12, and the second conductor layer 1312 of the third wiring 131C is formed on one side in the thickness direction of the insulating layer 12 so as to cover the first wiring of the third wiring 131C, and the second conductor layer 1322 is formed on one side in the thickness direction of the first conductor layer 1321 of each of the terminals 132 and 133.

[0147] In more detail, first, a plating resist R2 is bonded to one side in the thickness direction of the insulating layer 12 on which the seed layer is formed, and to cover the first conductor layer 1311 and the first conductor layer 1321. Then, the plating resist R2 is exposed to light while shielding the portions where the second conductor layers 1312 of the second wiring 131B and the third wiring 131C, and the second conductor layers 1322 of the terminals 132 and 133 are formed.

[0148] Next, the exposed plating resist R2 is developed. This removes the plating resist R2 from the light-shielded areas, exposing at least one selected from the group consisting of the seed layer, the first conductor layer 1311, and the first conductor layer 1321 in the areas where the second conductor layers 1312 of the second wiring 131B and the third wiring 131C, and the second conductor layers 1322 of the terminals 132 and 133, are formed. Meanwhile, the plating resist R2 in the exposed areas remains.

[0149] In the developed plating resist R2, the width of the portion where the second conductor layer 1312 of the third wiring 131C is formed is greater than the width of the first conductor layer 1311 of the third wiring 131C. Furthermore, the first conductor layer 1311 of the third wiring 131C is positioned in the widthwise center of the portion where the second conductor layer 1312 of the third wiring 131C is formed. On the other hand, although not shown, the width of the portion where the second conductor layer 1322 of terminals 132 and 133 is formed is the same as the width of the first conductor layer 1321 of terminals 132 and 133 (if the cross-sectional shape of terminals 132 and 133 is approximately rectangular), or smaller than the width of the first conductor layer 1321 of terminals 132 and 133 (if the cross-sectional shape of terminals 132 and 133 is approximately convex).

[0150] Next, electrolytic plating is used to form the second conductor layer 1312 of the second wiring 131B on one side in the thickness direction of the exposed seed layer, and the second conductor layer 1312 of the third wiring 131C on one side in the thickness direction of the exposed seed layer and the first conductor layer 1311, while also forming the second conductor layer 1322 of the terminals 132 and 133 on one side in the thickness direction of the first conductor layer 1321.

[0151] The formation of the second conductor layer 1312 and the second conductor layer 1322 completes the first wiring 131A, the second wiring 131B, the third wiring 131C, and the terminals 132 and 133.

[0152] In the formation of the second conductor layer 1312 of the third wiring 131C, at both ends in the width direction of the third wiring 131C, the plating grows from a seed layer located on one side in the thickness direction of the insulating layer 12, while at the center of the third wiring 131C in the width direction, the plating grows from one side in the thickness direction of the first conductor layer 1311 of the third wiring 131C. Then, at the center of the third wiring 131C in the width direction, the second conductor layer 1312 is laminated on one side in the thickness direction of the first conductor layer 1311. On the other hand, at both ends in the width direction of the third wiring 131C, the second conductor layer 1312 is laminated on one side in the thickness direction of the insulating layer 12. Therefore, as described above, the center of the third wiring 131C in the width direction protrudes toward one side in the thickness direction compared to the ends in the width direction of the third wiring 131C, due to the presence of the first conductor layer 1311.

[0153] On the other hand, in the formation of the second conductor layer 1322 of terminals 132 and 133, the plating grows uniformly from only one side in the thickness direction of the first conductor layer 1321 of terminals 132 and 133. As a result, one side in the thickness direction of the second conductor layer 1322 of terminals 132 and 133 becomes flat. Also, because the plating grows uniformly, the thickness T4 of terminals 132 and 133 is thicker than the thickness T3 of the third wiring 131C.

[0154] After the first wiring 131A, the second wiring 131B, the third wiring 131C, and terminals 132 and 133 are completed, the plating resist R2 is peeled off. Subsequently, the seed layer exposed by the peeling off of the plating resist R2 is removed by etching.

[0155] (4) Cover insulating layer formation process Next, as shown in Figure 6B, in the cover insulating layer formation step, a cover insulating layer 14 is formed so as to cover one side of the insulating layer 12 in the thickness direction and the conductor pattern 13. The cover insulating layer 14 is formed, for example, in the same manner as the insulating layer 12 described above.

[0156] (5) Etching process Next, in the etching process, the metal foil M is etched to form the metal support substrate 11 shown in Figure 2.

[0157] This results in the manufacture of the wiring circuit board 1 shown in Figure 1.

[0158] 4. Effects (1) According to the wiring circuit board 1, as shown in Figures 1 and 3, the wiring 131 includes a first wiring 131A, a second wiring 131B, and a third wiring 131C, where the thickness T2 of the second wiring 131B is thicker than the thickness T1 of the first wiring 131A, and the thickness T3 of the third wiring 131C is thicker than the thickness T2 of the second wiring 131B. Therefore, the degree of freedom in wiring design on the wiring circuit board 1 can be increased.

[0159] (2) According to the wiring circuit board 1, as shown in Figure 3, the third wiring 131C has a central portion and an end portion in the width direction, and the central portion protrudes toward one side in the thickness direction compared to the end portion. Therefore, it is possible to increase the rigidity of the third wiring 131C in the thickness direction while suppressing an increase in the rigidity of the third wiring 131C in the width direction. As a result, the rigidity of the third wiring portion 3C in the thickness direction can be increased without hindering the deformation of the third wiring portion 3C in the width direction. In addition, since the wiring circuit board 1 is equipped with a third wiring 131C with a relatively large wiring cross-sectional area, electrical resistance can be reduced.

[0160] (3) According to the wiring circuit board 1, as shown in Figure 3, the first wiring 131A has a first conductor layer 1311, the second wiring 131B has a second conductor layer 1312, and the third wiring 131C has a first conductor layer 1311 and a second conductor layer 1312 covering the first conductor layer 1311. Therefore, three types of wiring with different thicknesses (first wiring 131A, second wiring 131B, and third wiring 131C) can be formed by the simple process of forming two types of conductor layers, the first conductor layer 1311 and the second conductor layer 1312.

[0161] (4) According to the wiring circuit board 1, as shown in Figures 1 and 4, terminals 132 and 133 are further provided to connect to the wiring 131, and the thickness T4 of terminals 132 and 133 is greater than the thickness T3 of the third wiring 131C. Therefore, the design freedom of the wiring circuit board 1 can be further increased.

[0162] (5) According to the wiring circuit board 1, as shown in Figure 4, terminals 132 and 133 have a first conductor layer 1321 and a second conductor layer 1322 arranged on one side in the thickness direction of the first conductor layer 1321. Therefore, by the simple process of forming two types of conductor layers, the first conductor layer 1311 and the second conductor layer 1312, it is possible to form terminals 132 and 133 in addition to three types of wiring with different thicknesses (first wiring 131A, second wiring 131B, and third wiring 131C).

[0163] (5) According to the wiring circuit board 1, as shown in Figure 4, terminals 132 and 133 have a first conductor layer 1321 and a second conductor layer 1322 arranged on one side in the thickness direction of the first conductor layer 1321. Therefore, by the simple process of forming two types of conductor layers, the first conductor layer 1311 and the second conductor layer 1312, it is possible to form terminals 132 and 133 in addition to three types of wiring with different thicknesses (first wiring 131A, second wiring 131B, and third wiring 131C).

[0164] 5. Variations Next, a modified example will be described. In the modified example, the same reference numerals are used for components similar to those in the above-described embodiment, and their descriptions are omitted.

[0165] (1) In one embodiment of the wiring circuit board 1 described above, terminal 132C and terminal 133C are connected by a composite wiring consisting of a second wiring 131B and a third wiring 131C, but the invention is not limited to this.

[0166] As shown in Figure 7, terminals 132C and 133C may be connected by a third wire 131C.

[0167] In the wiring circuit board 1 shown in Figure 7, a third wire 131C is placed between the terminal arrangement sections 2A and 2B and the third wiring section 3C in each of the connecting sections 4A and 4B. In other words, a single third wire 131C is placed continuously between terminals 132C and 133C, connecting terminals 132C and 133C across the connecting section 4A, the third wiring section 3C, and the connecting section 4B. If terminals 132C and 133C are connected by a single third wire 131C, electrical resistance can be further reduced.

[0168] In other words, at least a third wiring 131C is provided in each of the connecting sections 4A and 4B. More specifically, a first wiring 131A, a second wiring 131B, and a third wiring 131C are provided in each of the connecting sections 4A and 4B.

[0169] Furthermore, as shown in Figure 8, the first conductor layer 1311 of the third wiring 131C is continuous with the first conductor layer 1321 of terminal 132C and the first conductor layer 1321 of terminal 133C, which will be described later. In addition, the second conductor layer 1312 of the third wiring 131C is continuous with the second conductor layer 1322 of terminal 132C and the second conductor layer 1322 of terminal 133C, which will be described later. Preferably, the first conductor layer 1311 of the third wiring 131C is made from the same metal as the first conductor layer 1321 of terminal 132C and the first conductor layer 1321 of terminal 133C, and preferably, the second conductor layer 1312 of the third wiring 131C is made from the same metal as the second conductor layer 1322 of terminal 132C and the second conductor layer 1322 of terminal 133C.

[0170] (2) The wiring circuit board 1 described above includes a first wiring section 3A, a second wiring section 3B, and a third wiring section 3C, but is not limited thereto.

[0171] In the wiring circuit board 1, the wiring 131 only needs to include a first wiring 131A, a second wiring 131B, and a third wiring 131C. If terminals 132C and 133C are connected by a composite wiring consisting of the second wiring 131B and the third wiring 131C, the wiring circuit board 1 does not need to have a second wiring section 3B. In other words, the wiring section 3 only needs to include at least a first wiring section 3A where the first wiring 131A is located and a third wiring section 3C where the third wiring 131C is located. [Explanation of symbols]

[0172] 1 Wiring circuit board 2 Terminal arrangement area 3 Wiring section 4 Connecting part 11 Metal support substrate 12. Insulating layer (base insulating layer) 13 Conductor Patterns 14 Cover insulation layer 131A First Wiring 131B 2nd wiring 131C 3rd wiring

Claims

1. Metal support substrate and An insulating layer disposed on one side in the thickness direction of the metal support substrate, A conductor pattern arranged on one side in the thickness direction of the insulating layer and Equipped with, The conductor pattern comprises wiring, The aforementioned wiring includes a first wiring, a second wiring, and a third wiring. The thickness T2 of the second wiring is greater than the thickness T1 of the first wiring. A wiring circuit board in which the thickness T3 of the third wiring is thicker than the thickness T2 of the second wiring.

2. The third wiring has a central portion and an end portion in the width direction perpendicular to the thickness direction and the direction in which the wiring extends, The wiring circuit board according to claim 1, wherein the central portion protrudes toward one side in the thickness direction compared to the end portion.

3. The first wiring has a first conductor layer, The second wiring has a second conductor layer, The wiring circuit board according to claim 1, wherein the third wiring comprises the first conductor layer and the second conductor layer covering the first conductor layer.

4. The wiring circuit board according to any one of claims 1 to 3, wherein the conductor pattern further comprises terminals connected to the wiring.

5. The wiring circuit board according to claim 4, wherein the thickness T4 of the terminal is thicker than the thickness T3 of the third wiring.

6. The wiring circuit board according to claim 4, wherein the terminal has a first conductor layer and a second conductor layer disposed on one side in the thickness direction of the first conductor layer.

7. The aforementioned wiring circuit board is A terminal arrangement section where the aforementioned terminals are arranged, A wiring section on which at least one selected from the group consisting of the first wiring, the second wiring, and the third wiring is arranged, A connecting portion that connects the terminal arrangement portion and the wiring portion. Equipped with, The wiring circuit board according to claim 4, wherein at least one selected from the group consisting of the first wiring, the second wiring, and the third wiring is arranged in the connecting portion.

8. The wiring circuit board according to claim 7, wherein at least the third wiring is arranged in the connecting portion.

9. The wiring section includes at least a first wiring section where the first wiring is arranged and a third wiring section where the third wiring is arranged. The wiring circuit board according to claim 7, wherein the first wiring section and the third wiring section are arranged at a distance from each other in the thickness direction and in the width direction perpendicular to the direction in which the wiring extends.

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