Wired circuit board

Abstract

To provide a wiring circuit board capable of increasing rigidity of a wiring part in a thickness direction while allowing movement of the wiring part in a second direction.SOLUTION: The wired circuit substrate 1 includes a wired portion 3A and a supporting portion 3A supporting one end portion of the wired portion 2A. The interconnection part 3A includes a first insulating layer 12, an interconnection 133A, a metallic support layer 11, and a covering layer 15. The covering layer 15 has a first portion 151 covering the side S1 of the metallic support layer 11 and a second portion 152 covering the other side S2 of the metallic support layer 11 in the thickness direction. The thickness T12 of the second portion 152 is larger than the thickness T11 of the first portion 151.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a printed circuit board. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known a printed circuit board having a plurality of wiring portions arranged at intervals from each other (see, for example, Patent Document 1 below).

[0003] In this wired circuit board, the thickness of the wiring portion is greater than the width of the wiring portion (more than twice as large), so the wiring portion can move more easily in the width direction than in the thickness direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-212656 Summary of the Invention [Problem to be solved by the invention]

[0005] In a wired circuit board such as that described in Patent Document 1, it may be desirable to increase the rigidity of the wiring portion in the thickness direction while allowing the wiring portion to move in the width direction.

[0006] The present invention provides a wired circuit board that can increase the rigidity of the wiring portion in the thickness direction while allowing the wiring portion to move in a second direction. [Means for solving the problem]

[0007] The present invention [1] includes a wired circuit board comprising a wiring portion extending in a first direction and a support portion supporting one end of the wiring portion, wherein the wiring portion comprises an insulating layer, a wiring disposed on one side of the insulating layer in a thickness direction of the insulating layer and extending in the first direction perpendicular to the thickness direction, a metal support layer disposed on the other side of the insulating layer in the thickness direction, and a coating layer coating the metal support layer, wherein the coating layer has a first portion coating a side surface of the metal support layer in a second direction perpendicular to both the first direction and the thickness direction, and a second portion coating the surface of the metal support layer on the other side in the thickness direction, and the thickness of the second portion in the thickness direction is greater than the thickness of the first portion in the second direction.

[0008] According to this configuration, the covering layer has a first portion covering the side surface of the metal support layer and a second portion covering the surface on the other side of the metal support layer in the thickness direction, and the thickness of the second portion is greater than the thickness of the first portion.

[0009] Therefore, the metal support layer can be reinforced in both the second direction and the thickness direction, and the rigidity of the metal support layer in the thickness direction can be increased more than the rigidity of the metal support layer in the second direction.

[0010] As a result, the rigidity of the wiring portion in the thickness direction can be increased while allowing the wiring portion to move in the second direction.

[0011] The present invention [2] includes the wired circuit board of [1] above, wherein the wired circuit board further comprises a second wiring portion arranged at a distance from the wiring portion in the second direction and extending in the first direction, and the support portion supports the one end of the wiring portion and one end of the second wiring portion.

[0012] The present invention [3] includes the wired circuit board according to the above [1] or [2], wherein the width of the metal support layer in the second direction is narrower than the width of the insulating layer.

[0013] The present invention [4] includes the wired circuit board of any one of the above [1] to [3], wherein the ratio of the thickness of the metal support layer in the thickness direction to the width of the metal support layer in the second direction is 2 or more.

[0014] The present invention [5] includes the wired circuit board of any one of [1] to [4] above, wherein the thickness of the first portion in the second direction increases from one end of the metal support layer in the thickness direction toward the other end of the metal support layer in the thickness direction, and the thickness of the second portion in the thickness direction increases from both ends of the metal support layer in the second direction toward the center of the metal support layer in the second direction.

[0015] With this configuration, by increasing the thickness of the coating layer from one end of the metal support layer to the other end of the metal support layer, the thickness of the second portion in the thickness direction can be reliably made thicker than the thickness of the first portion in the second direction.

[0016] Therefore, it is possible to reliably increase the rigidity of the wiring portion in the thickness direction while allowing the wiring portion to move in the second direction.

[0017] The present invention [6] includes the wired circuit board of any one of the above [1] to [5], wherein the covering layer is made of a metal different from that of the metal support layer.

[0018] The present invention [7] includes the wired circuit board according to any one of the above [1] to [6], wherein the thermal conductivity of the coating layer is higher than the thermal conductivity of the metal support layer.

[0019] According to this configuration, the covering layer can ensure the rigidity of the wiring portion while improving heat dissipation.

[0020] The present invention [8] includes the wired circuit board of any one of the above [1] to [7], wherein the electrical conductivity of the coating layer is higher than the electrical conductivity of the metal support layer.

[0021] According to this configuration, the coating layer can ensure the rigidity of the wiring portion while improving the electrical conductivity. [Effects of the Invention]

[0022] According to the wired circuit board of the present invention, the rigidity of the wiring portion in the thickness direction can be increased while allowing the wiring portion to move in the second direction. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a plan view of a printed circuit board according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the printed circuit board shown in FIG. 1 taken along the line AA. [Figure 3] 3A to 3C are process diagrams showing the manufacturing process of the wired circuit board shown in FIG. 1, where FIG. 3A shows the first insulating layer forming process, FIG. 3B shows the circuit pattern forming process, and FIG. 3C shows the second insulating layer forming process. [Figure 4] 4A and 4B are process diagrams showing the manufacturing process of the wired circuit board shown in FIG. 1 following FIG. 3C, where FIG. 4A shows the etching step and FIG. 4B shows the coating layer forming step. [Figure 5] Figures 5A to 5D are process diagrams showing a modified example of the manufacturing process for a wired circuit board, where Figure 5A shows a first insulating layer forming process, Figure 5B shows a circuit pattern forming process, Figure 5C shows a second insulating layer forming process, and Figure 5D shows a removal process. [Figure 6] 6A to 6C are process diagrams showing a modified example of the manufacturing process of a printed circuit board following FIG. 5D, where FIG. 6A shows a deposition process, FIG. 6B shows an etching process, and FIG. 6C shows a coating layer formation process. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1. Wiring circuit board As shown in FIG. 1, the wired circuit board 1 includes a plurality of support portions 2A, 2B and a plurality of wiring portions 3A, 3B.

[0025] The support portion 2A and the support portion 2B are arranged at a distance from each other. The shapes of the support portion 2A and the support portion 2B are not limited. The support portion 2A supports one end portion of each of the wiring portions 3A and 3B. In this embodiment, terminals 131A, 131B, and 131C of the circuit pattern 13, which will be described later, are arranged on the support portion 2A. The support portion 2B supports the other end portion of each of the wiring portions 3A and 3B. In this embodiment, terminals 132A, 132B, and 132C of the circuit pattern 13, which will be described later, are arranged on the support portion 2B.

[0026] The wiring portions 3A and 3B are disposed between the support portion 2A and the support portion 2B. Each of the wiring portions 3A and 3B extends in a first direction. More specifically, each of the wiring portions 3A and 3B has a width in a second direction and extends in the first direction. The first direction is the direction in which the wiring 133A of the circuit pattern 13 described below extends. The first direction is perpendicular to the thickness direction of the wired circuit board 1. The second direction is perpendicular to both the thickness direction and the first direction. The wiring portion 3B is disposed at a distance from the wiring portion 3A in the second direction. The wiring portion 3B extends in the first direction parallel to the wiring portion 3A. One end of each of the wiring portions 3A and 3B is connected to the support portion 2A. The other end of each of the wiring portions 3A and 3B is connected to the support portion 2B. The shapes of each of the wiring portions 3A and 3B are not limited. Each of the wiring portions 3A and 3B may be linear or curved. At least a portion of wirings 133A and 133B of the circuit pattern 13, which will be described later, is disposed on the wiring portion 3A. At least a portion of wirings 133C of the circuit pattern 13, which will be described later, is disposed on the wiring portion 3B.

[0027] The width W0 of each of the wiring portions 3A and 3B is, for example, 10 μm to 300 μm, or preferably 50 μm to 250 μm. Note that the "width" refers to the maximum length in the second direction.

[0028] The distance D1 between the wiring portion 3A and the wiring portion 3B is in the range of, for example, 5 μm to 300 μm, or preferably 10 μm to 250 μm.

[0029] As shown in FIG. 2, the wired circuit board 1 has a metal support layer 11, a first insulating layer 12, a circuit pattern 13, a second insulating layer 14, and a cover layer 15.

[0030] (1) Metal support layer The metal support layer 11 is disposed on each of the wiring portions 3A and 3B. That is, each of the wiring portions 3A and 3B has a metal support layer 11. The metal support layer 11 is also disposed on the support portions 2A and 2B (see FIG. 1). The metal support layer 11 is disposed on the other side of the first insulating layer 12 in the thickness direction. The metal support layer 11 supports the first insulating layer 12, the circuit pattern 13, and the second insulating layer 14. Examples of materials for the metal support layer 11 include copper, iron, nickel, titanium, chromium, tin, zinc, aluminum, and alloys thereof. Examples of alloys include copper alloys and stainless steel. Preferred examples of materials for the metal support layer 11 include copper alloys and stainless steel.

[0031] The thermal conductivity of the metal support layer 11 is, for example, 50 W / m·K to 350 W / m·K. The thermal conductivity of the metal support layer 11 may be less than 300 W / m·K.

[0032] The electrical conductivity of the metal support layer 11 is, for example, 1.25×10 6 S / m~10.44×10 6 S / m, preferably 6.94 x 10 6 S / m~8.12×10 6 S / m.

[0033] The metal support layer 11 has a thickness T1 in the range of, for example, 10 μm to 300 μm, or preferably 50 μm to 250 μm.

[0034] The metal support layer 11 of each of the wiring portions 3A and 3B has a width in the second direction and extends in the first direction (see FIG. 1). In the second direction, the width W1 of the metal support layer 11 of each of the wiring portions 3A and 3B is preferably narrower than the width W2 of the first insulating layer 12. In this embodiment, the width W2 of the first insulating layer 12 is the same as the width W0 of each of the wiring portions 3A and 3B (see FIG. 1). Note that in the second direction, the width W1 of the metal support layer 11 of each of the wiring portions 3A and 3B may be the same as the width W2 of the first insulating layer 12.

[0035] The width W1 of the metal support layer 11 is in the range of, for example, 10 μm to 100 μm, or preferably 15 μm to 50 μm.

[0036] The ratio (T1 / W1) of the thickness T1 of the metal support layer 11 in the thickness direction to the width W1 of the metal support layer 11 in the second direction is, for example, not less than 2, or preferably not less than 5. Hereinafter, the ratio (T1 / W1) is defined as the aspect ratio of the metal support layer 11.

[0037] When the aspect ratio (T1 / W1) of the metal support layer 11 is equal to or greater than the above lower limit, the rigidity of the wiring portion 3A in the thickness direction can be ensured.

[0038] The aspect ratio (T1 / W1) of the metal support layer 11 is, for example, 30 or less, or preferably 10 or less.

[0039] The aspect ratio (T1 / W1) of the metal support layer 11 may be 2-30, or 5-10.

[0040] The metal support layer 11 of the wiring portion 3B is disposed at a distance from the metal support layer 11 of the wiring portion 3A in the second direction. The distance D2 between the metal support layer 11 of the wiring portion 3A and the metal support layer 11 of the wiring portion 3B is wider than the distance D1 between the wiring portion 3A and the wiring portion 3B.

[0041] The distance D2 is in the range of, for example, 50 μm to 300 μm, or preferably 80 μm to 150 μm.

[0042] (2) First insulating layer The first insulating layer 12 is disposed on each of the wiring portions 3A and 3B. That is, each of the wiring portions 3A and 3B has a first insulating layer 12. The first insulating layer 12 is also disposed on the support portions 2A and 2B (see FIG. 1). The first insulating layer 12 is disposed on one side of the metal support layer 11 in the thickness direction of the metal support layer 11. The first insulating layer 12 is disposed on one surface of the metal support layer 11 in the thickness direction. The first insulating layer 12 is disposed between the metal support layer 11 and the circuit pattern 13 in the thickness direction. The first insulating layer 12 insulates the metal support layer 11 from the circuit pattern 13. The first insulating layer 12 is made of a resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester.

[0043] (3) Circuit pattern The circuit pattern 13 is disposed on one side of the first insulating layer 12 in the thickness direction. The circuit pattern 13 is disposed on one surface of the first insulating layer 12 in the thickness direction. The circuit pattern 13 is disposed on the opposite side of the first insulating layer 12 from the metal support layer 11 in the thickness direction. The shape of the circuit pattern 13 is not limited.

[0044] As shown in FIG. 1, the circuit pattern 13 has a plurality of terminals 131A, 131B, and 131C, a plurality of terminals 132A, 132B, and 132C, and a plurality of wirings 133A, 133B, and 133C.

[0045] The terminals 131A, 131B, and 131C are arranged on the support portion 2A. Each of the terminals 131A, 131B, and 131C has a square land shape. The terminals 131A, 131B, and 131C are aligned in the second direction. The terminals 131A, 131B, and 131C are arranged at intervals from each other in the second direction.

[0046] The terminals 132A, 132B, and 132C are arranged on the support portion 2B. Each of the terminals 132A, 132B, and 132C has a square land shape. The terminals 132A, 132B, and 132C are aligned in the second direction. The terminals 132A, 132B, and 132C are arranged at intervals from each other in the second direction.

[0047] Each of the terminals 131A to 131C and the terminals 132A to 132C includes a first conductor layer 1311 and a second conductor layer 1312.

[0048] The first conductor layer 1311 is disposed on the first insulating layer 12 in the thickness direction. The first conductor layer 1311 is made of a metal. Examples of the metal include copper, silver, gold, iron, aluminum, chromium, and alloys thereof. To obtain good electrical properties, copper is preferably used as the metal.

[0049] The second conductor layer 1312 is disposed on the first conductor layer 1311 in the thickness direction. The second conductor layer 1312 is made of a metal. Examples of the metal include the same metal as the first conductor layer 1311. The second conductor layer 1312 is preferably made of the same metal as the first conductor layer 1311.

[0050] The wiring 133A electrically connects the terminal 131A and the terminal 132A. The wiring 133A extends in a first direction. One end of the wiring 133A is connected to the first conductor layer 1311 of the terminal 131A. The other end of the wiring 133A is connected to the first conductor layer 1311 of the terminal 132A. The wiring 133A is made of the same material as the first conductor layer 1311. At least a portion of the wiring 133A is disposed in the wiring section 3A. That is, the wiring section 3A has the wiring 133A. The wiring 133A is also disposed on one side of the first insulating layer 12 in the thickness direction of the first insulating layer 12 (see FIG. 2). The wiring 133A is, for example, a signal wiring.

[0051] The wiring 133B electrically connects the terminal 131B and the terminal 132B. The wiring 133B extends in a first direction. One end of the wiring 133B is connected to the first conductor layer 1311 of the terminal 131B. The other end of the wiring 133B is connected to the first conductor layer 1311 of the terminal 132B. The wiring 133B is made of the same material as the first conductor layer 1311. At least a portion of the wiring 133B is arranged in the wiring section 3A. That is, the wiring section 3A may have a plurality of wirings 133A and 133B. The wirings 133A and 133B are aligned in the second direction. The wirings 133A and 133B are arranged at an interval from each other in the second direction. The wiring 133B is, for example, a signal wiring. The wiring 133B may form a differential pair together with the wiring 133A.

[0052] The wiring 133C electrically connects the terminal 131C and the terminal 132C. The wiring 133C extends in a first direction. One end of the wiring 133C is connected to the second conductor layer 1312 of the terminal 131C. The other end of the wiring 133C is connected to the second conductor layer 1312 of the terminal 132C. The wiring 133C is made of the same material as the second conductor layer 1312. At least a portion of the wiring 133C is disposed in the wiring section 3B. That is, the wiring section 3B includes the wiring 133C. The wiring 133C is, for example, a power supply wiring.

[0053] (4) Second insulating layer 2, the second insulating layer 14 covers all of the wirings 133A, 133B, and 133C. The second insulating layer 14 is disposed on the first insulating layer 12 in the thickness direction. The second insulating layer 14 does not cover the terminals 131A to 131C and the terminals 132A to 132C. The second insulating layer 14 is made of a resin. Examples of resins include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester.

[0054] (5) Covering layer The covering layer 15 covers the metal support layer 11 of the wiring portions 3A and 3B. That is, each of the wiring portions 3A and 3B has a covering layer 15. The covering layer 15 may also cover the metal support layer 11 of the support portions 2A and 2B. Examples of materials for the covering layer 15 include copper, nickel, gold, and silver. A preferred material for the covering layer 15 is copper. The covering layer 15 is preferably made of a metal different from that of the metal support layer 11.

[0055] The thermal conductivity of the coating layer 15 is preferably higher than the thermal conductivity of the metal support layer 11. The thermal conductivity of the coating layer 15 is, for example, 300 W / m·K or more, preferably 350 W / m·K or more, and for example, 450 W / m·K or less.

[0056] The electrical conductivity of the coating layer 15 is preferably higher than the electrical conductivity of the metal support layer 11. The electrical conductivity of the coating layer 15 is, for example, 40×10 6 S / m or more, preferably 50×10 6 S / m or more, for example, 100×10 6 S / m or less.

[0057] The cover layer 15 has a first portion 151 and a second portion 152 .

[0058] The first portion 151 covers the side surface S1 of the metal support layer 11 in the second direction. The first portion 151 has a thickness in the second direction and extends in the thickness direction. The thickness T11 of the first portion 151 in the second direction increases from one end E1 of the metal support layer 11 in the thickness direction to the other end E2 of the metal support layer 11 in the thickness direction. In other words, the thickness T11 of the first portion 151 is minimum at one end of the first portion 151 in the thickness direction and maximum at the other end of the first portion 151 in the thickness direction.

[0059] The minimum value of the thickness T11 of the first portion 151 is, for example, not less than 0.02 μm, or preferably not less than 0.1 μm. The maximum value of the thickness T11 of the first portion 151 is, for example, not more than 1.0 μm, or preferably not more than 0.5 μm.

[0060] The second portion 152 covers the surface S2 on the other side of the metal support layer 11 in the thickness direction. The second portion 152 has a thickness in the thickness direction and extends in the second direction. The thickness T12 of the second portion 152 in the thickness direction increases from both ends of the metal support layer 11 in the second direction toward the center of the metal support layer 11 in the second direction. In other words, the thickness T12 of the second portion 152 is minimum at both ends of the second portion 152 in the second direction and maximum at the center of the second portion 152 in the second direction.

[0061] The minimum value of the thickness T12 of the second portion 152 is, for example, 0.02 μm or more, or preferably 0.1 μm or more. The maximum value of the thickness T12 of the second portion 152 is, for example, 1.0 μm or less, or preferably 1.5 μm or less.

[0062] The thickness T12 of the second portion 152 in the thickness direction is thicker than the thickness T11 of the first portion 151 in the second direction. Specifically, the maximum value of the thickness T12 of the second portion 152 is thicker than the maximum value of the thickness T11 of the first portion 151. Therefore, the rigidity of the wiring portion 3A in the thickness direction can be increased so as not to hinder the movement of the wiring portion 3A in the second direction.

[0063] The ratio (T12 / T11) of the thickness T12 of the second portion 152 to the thickness T11 of the first portion 151 is in the range of, for example, 1.1 to 10, or preferably 1.1 to 3.

[0064] 2. Manufacturing method of printed circuit board Next, a method for manufacturing the wired circuit board 1 will be described.

[0065] The method for manufacturing the wired circuit board 1 includes a first insulating layer forming step (see FIG. 3A), a circuit pattern forming step (see FIG. 3B), a second insulating layer forming step (see FIG. 3C), an etching step (see FIG. 4A), and a cover layer forming step (see FIG. 4B).

[0066] (1) First insulating layer formation process 3A, in the first insulating layer forming step, the first insulating layer 12 is formed on a metal substrate S. The substrate S is the material of the metal support layer 11.

[0067] Specifically, in the first insulating layer forming step, first, a photosensitive resin solution (varnish) is applied onto the substrate S and dried to form a photosensitive resin coating. Next, the photosensitive resin coating is exposed to light and developed. This results in the first insulating layer 12.

[0068] (2) Circuit pattern formation process Next, as shown in FIG. 3B, in the circuit pattern forming step, a circuit pattern 13 is formed on the first insulating layer 12.

[0069] More specifically, in the circuit pattern forming step, first conductor layers 1311 (see FIG. 1) of terminals 131A to 131C and terminals 132A to 132C, and wirings 133A and 133B (see FIG. 1) are formed on first insulating layer 12.

[0070] First, a seed layer is formed in the thickness direction on one surface of the first insulating layer 12 and one surface of the substrate S. The seed layer is formed by, for example, sputtering. Examples of materials for the seed layer include chromium, copper, nickel, titanium, and alloys thereof.

[0071] The seed layer is then coated with a plating resist.

[0072] Next, the plating resist is exposed and developed. This removes the plating resist from the portions where the first conductor layer 1311 and the wirings 133A and 133B are to be formed, exposing the seed layer in the portions where the first conductor layer 1311 and the wirings 133A and 133B are to be formed. On the other hand, the plating resist remains in the portions where the first conductor layer 1311 and the wirings 133A and 133B are not to be formed.

[0073] Next, the first conductor layer 1311 and the wirings 133A and 133B are formed on the exposed seed layer by electrolytic plating.

[0074] After the electrolytic plating is completed, the plating resist is stripped off.

[0075] Next, in the circuit pattern forming step, a second conductor layer 1312 (see FIG. 1) is formed on the first conductor layer 1311, and wiring 133C (see FIG. 1) is formed on the first insulating layer 12.

[0076] First, the first conductor layer 1311 and the seed layer are covered with a plating resist.

[0077] Next, the plating resist is exposed and developed. This removes the plating resist from the areas where the second conductor layer 1312 and the wiring 133C will be formed, exposing the first conductor layer 1311 or the seed layer in the areas where the second conductor layer 1312 and the wiring 133C will be formed. On the other hand, the plating resist remains in the areas where the second conductor layer 1312 and the wiring 133C will not be formed.

[0078] Next, second conductor layer 1312 and wiring 133C are formed on the exposed first conductor layer 1311 or the seed layer by electrolytic plating.

[0079] After the electrolytic plating is completed, the plating resist is stripped off, and the seed layer exposed by the stripping of the plating resist is removed by etching.

[0080] As a result, the circuit pattern 13 is formed on the first insulating layer 12.

[0081] (3) Second insulating layer formation process Next, as shown in FIG. 3C, in the second insulating layer forming step, second insulating layer 14 is formed on first insulating layer 12.

[0082] More specifically, in the second insulating layer forming process, a photosensitive resin solution (varnish) is first applied onto the circuit pattern 13, the first insulating layer 12, and the substrate S, and then dried to form a photosensitive resin coating.

[0083] Next, the photosensitive resin coating is exposed to light and developed, thereby forming the second insulating layer 14 on the first insulating layer 12.

[0084] (4) Etching process Next, as shown in FIG. 4A, in the etching step, the substrate S is etched to form the metal support layer 11.

[0085] (5) Covering layer formation process Next, as shown in FIG. 4B, in the coating layer forming step, a coating layer 15 is formed on the surface of the metal support layer 11.

[0086] More specifically, in the covering layer forming step, first, a plating resist R1 is formed on the entire one surface of the first insulating layer 12. The plating resist R1 covers the circuit pattern 13 and the second insulating layer 14. On the other hand, no plating resist is formed on the other surface of the first insulating layer 12.

[0087] Next, a coating layer 15 is formed on the surface of the metal support layer 11, preferably by electrolytic plating.

[0088] At this time, the plating solution flows more easily near the other end E2 of the metal support layer 11 in the thickness direction than near one end E1 of the metal support layer 11 in the thickness direction. Furthermore, in electrolytic plating, charges tend to concentrate at the corner of the other end E2 of the metal support layer 11. Therefore, the coating layer 15 formed near the other end E2 grows more easily than the coating layer 15 formed near the one end E1.

[0089] As a result, the thickness T12 of the second portion 152 is greater than the thickness T11 of the first portion 151, as described above.

[0090] In this way, the wired circuit board 1 is obtained.

[0091] 3. Effects (1) According to the wired circuit board 1, as shown in Fig. 2, the covering layer 15 has a first portion 151 covering the side surface S1 of the metal support layer 11 and a second portion 152 covering the surface S2 on the other side in the thickness direction of the metal support layer 11. The thickness T12 of the second portion 152 is thicker than the thickness T11 of the first portion 151.

[0092] Therefore, the metal support layer 11 can be reinforced in both the second direction and the thickness direction, and the rigidity of the metal support layer 11 in the thickness direction can be increased more than the rigidity of the metal support layer 11 in the second direction.

[0093] As a result, the rigidity of the wiring parts 3A, 3B in the thickness direction can be increased while allowing the wiring parts 3A, 3B to move in the second direction.

[0094] (2) According to the wired circuit board 1, as shown in Fig. 2, the thickness T11 of the first portion 151 increases from one end E1 of the metal support layer 11 toward the other end E2 of the metal support layer 11. Furthermore, the thickness T12 of the second portion 152 increases from both end portions of the metal support layer 11 in the second direction toward the center of the metal support layer 11 in the second direction.

[0095] Therefore, by increasing the thickness of the coating layer 15 from one end E1 of the metal support layer 11 toward the other end E2 of the metal support layer 11, the thickness T12 of the second portion 152 can be reliably made thicker than the thickness T11 of the first portion 151.

[0096] As a result, the rigidity of the wiring parts 3A, 3B in the thickness direction can be reliably increased while allowing the wiring parts 3A, 3B to move in the second direction.

[0097] (3) In the wired circuit board 1 , the thermal conductivity of the covering layer 15 is higher than the thermal conductivity of the metal support layer 11 .

[0098] Therefore, the coating layer 15 can ensure the rigidity of the wiring portions 3A and 3B while improving the heat dissipation performance.

[0099] (4) In the wired circuit board 1 , the electrical conductivity of the covering layer 15 is higher than the electrical conductivity of the metal support layer 11 .

[0100] Therefore, the coating layer 15 can ensure the rigidity of the wiring portions 3A and 3B, while also improving the electrical conductivity.

[0101] 4. Variations Next, a modified example will be described. In the modified example, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0102] The method for manufacturing the wired circuit board 1 may include a first insulating layer forming step (see FIG. 5A), a circuit pattern forming step (see FIG. 5B), a second insulating layer forming step (see FIG. 5C), a removing step (see FIG. 5D), a depositing step (see FIG. 6A), an etching step (see FIG. 6B), and a covering layer forming step (see FIG. 6C).

[0103] 5A, in the first insulating layer forming step of the modified example, the first insulating layer 12 is formed on the entire surface of the metal base material S. In the modified example, the base material S is not the material of the metal support layer 11, and is removed in the removing step.

[0104] Next, as shown in FIG. 5B, in the circuit pattern forming step, a circuit pattern 13 is formed on the first insulating layer 12 in the same manner as in the above-described embodiment.

[0105] Next, as shown in FIG. 5C, in the second insulating layer forming step, a second insulating layer 14 is formed on the first insulating layer 12 in the same manner as in the above-described embodiment.

[0106] Next, as shown in FIG. 5D, in the removal step, the substrate S is removed by, for example, etching.

[0107] Next, as shown in FIG. 6A, in the deposition step, metal is deposited on the other surface of first insulating layer 12 in the thickness direction to form metal support layer 11.

[0108] Specifically, in the deposition step, a seed layer is first formed on the other surface of the first insulating layer 12 in the thickness direction. The seed layer is formed by, for example, sputtering. Examples of materials for the seed layer include chromium, copper, nickel, titanium, and alloys thereof.

[0109] The seed layer is then coated with plating resist R2.

[0110] Next, the plating resist R2 is exposed and developed, whereby the plating resist R2 is removed from the area where the metal support layer 11 is to be formed, exposing the seed layer in the area where the metal support layer 11 is to be formed. On the other hand, the plating resist R2 remains in the area where the metal support layer 11 is not to be formed.

[0111] Next, metal is deposited on the exposed seed layer by electrolytic plating to form the metal support layer 11 .

[0112] After the electrolytic plating is completed, the plating resist R2 is stripped off, and the seed layer exposed by the stripping of the plating resist R2 is removed by etching.

[0113] As a result, metal support layer 11 is formed on the other surface of first insulating layer 12.

[0114] Next, as shown in FIG. 6B, in the etching step, the first insulating layer 12 between the wiring portion 3A and the wiring portion 3B is etched by, for example, laser etching.

[0115] Next, as shown in FIG. 6C, in the coating layer forming step, a coating layer 15 is formed on the surface of the metal support layer 11 in the same manner as in the above-described embodiment.

[0116] This modification also provides the same effects as those of the above embodiment. [Explanation of symbols]

[0117] 1 Wiring circuit board 2A Support part 3A wiring section 3B Wiring section (2nd wiring section) 11 Metal support layer 15 Covering layer 133A wiring 151 Part 1 152 Part 2 E1 One end of the metal support layer E2 Other end of metal support layer S1 Side of metal support layer S2: The other surface of the metal support layer W1 Width of metal support layer W2 Width of the first insulating layer T1 Thickness of metal support layer T11 Thickness of the first part T12 Second part thickness

Claims

1. a wiring portion extending in a first direction; a support portion that supports one end of the wiring portion; Equipped with The wiring portion is an insulating layer; a wiring disposed on one side of the insulating layer in a thickness direction of the insulating layer and extending in the first direction perpendicular to the thickness direction; a metal support layer disposed on the other side of the insulating layer in the thickness direction; a coating layer that coats the metal support layer; and The coating layer is a first portion covering a side surface of the metal support layer in a second direction perpendicular to both the first direction and the thickness direction; a second portion covering the surface of the metal support layer on the other side in the thickness direction; and The thickness of the second portion in the thickness direction is greater than the thickness of the first portion in the second direction.

2. The printed circuit board is a second wiring portion disposed at an interval from the wiring portion in the second direction and extending in the first direction; The printed circuit board according to claim 1 , wherein the support portion supports the one end of the wiring portion and one end of the second wiring portion.

3. The printed circuit board according to claim 1 , wherein the width of the metal support layer in the second direction is narrower than the width of the insulating layer.

4. The printed circuit board according to claim 1 , wherein a ratio of the thickness of the metal support layer in the thickness direction to the width of the metal support layer in the second direction is 2 or more.

5. a thickness of the first portion in the second direction increasing from one end of the metal support layer in the thickness direction to the other end of the metal support layer in the thickness direction, The printed circuit board according to claim 1 , wherein the thickness of the second portion in the thickness direction increases from both ends of the metal support layer in the second direction toward the center of the metal support layer in the second direction.

6. The printed circuit board according to claim 1 , wherein the covering layer is made of a metal different from that of the metal supporting layer.

7. The printed circuit board according to claim 1 , wherein the thermal conductivity of the cover layer is higher than the thermal conductivity of the metal support layer.

8. The printed circuit board according to claim 1 , wherein the electrical conductivity of the cover layer is higher than the electrical conductivity of the metal support layer.

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