Wiring circuit board

Abstract

A wired circuit board is provided that is suitable for adjusting the characteristic impedance of a terminal portion while ensuring the supporting strength for the terminal portion. [Solution] A wired circuit board X1 of the present invention includes a metal supporting board (10), an insulating layer (20), and a conductor layer (30) in this order in the thickness direction T. The conductor layer (30) includes at least one terminal portion (31) and a wiring portion (32) extending from the terminal portion (31). The metal supporting board (10) has an opening (10A). The opening (10A) penetrates the metal supporting board (10) in the thickness direction T and faces the terminal portion (31) via the insulating layer (20). The opening (10A) has a first opening peripheral edge (11) on one side in the thickness direction T and a second opening peripheral edge (12) on the other side in the thickness direction T. In a projected view in the thickness direction T, the second opening peripheral edge (12) is disposed outside the first opening peripheral edge (11) and extends along the first opening peripheral edge (11).

Description

Technical Field

[0001] The present invention relates to a wired circuit board. Background Art

[0002] A wired circuit board including a metal supporting substrate, an insulating layer on the metal supporting substrate, and a conductor layer on the insulating layer is known. The conductor layer includes a wiring portion and a terminal portion connected to the wiring portion. In such a wired circuit board, for impedance matching between the wiring portion and the terminal portion, for example, the characteristic impedance of the terminal portion is adjusted. The characteristic impedance of the terminal portion is adjusted, for example, by forming an opening facing the terminal portion via the insulating layer in the metal supporting substrate. Such a wired circuit board is described, for example, in Patent Document 1 below. Prior Art Document Patent Document

[0003] Patent Document 1 Japanese Unexamined Patent Publication No. 2012-235013 Summary of the Invention Problem to be Solved by the Invention

[0004] In a projected view in the thickness direction of the wired circuit board, the larger the area of the opening relative to the area of the terminal portion, the lower the supporting strength of the terminal portion provided by the metal supporting substrate. Therefore, if the opening is too large relative to the terminal portion, the supporting strength of the terminal portion provided by the metal supporting substrate becomes insufficient. Terminals of external components cannot be properly joined to a terminal portion with insufficient supporting strength. On the other hand, adjustment of characteristic impedance may be insufficient because an opening of sufficient size cannot be formed.

[0005] The present invention provides a wired circuit board suitable for adjusting the characteristic impedance of a terminal portion while securing the supporting strength for the terminal portion. Means for Solving the Problem

[0006] The present invention [1] includes a wiring circuit board comprising a metal support substrate, an insulating layer, and a conductor layer, in this order toward one side in the thickness direction, wherein the conductor layer includes at least one terminal portion and a wiring portion extending from the terminal portion, the metal support substrate has an opening that penetrates the metal support substrate in the thickness direction and faces the terminal portion via the insulating layer, the opening has a first opening peripheral edge on one side in the thickness direction and a second opening peripheral edge on the other side in the thickness direction, and in a projection view in the thickness direction, the second opening peripheral edge is located outside the first opening peripheral edge and extends along the first opening peripheral edge.

[0007] In the wiring circuit board of the present invention, as described above, an opening facing the terminal portion is formed in the metal support substrate via an insulating layer. Such a configuration is suitable for adjusting the characteristic impedance of the terminal portion. In addition, in a projection view in the thickness direction of the wiring circuit board, the second opening edge is positioned outside the first opening edge and extends along the first opening edge. That is, in the opening, the opening area at one end in the thickness direction (terminal portion side) is relatively small, and the opening area at the other end in the thickness direction is relatively large. Such a configuration is suitable for adjusting the characteristic impedance of the terminal portion by ensuring a wide opening space in the opening while suppressing a decrease in the support strength of the terminal portion by the metal support substrate. Therefore, this wiring circuit board is suitable for adjusting the characteristic impedance of the terminal portion while ensuring support strength for the terminal portion.

[0008] The present invention [2] includes the wiring circuit board described in [1] above, wherein, in the projected view, the entirety of the first aperture peripheral edge is located inside the terminal portion.

[0009] Such a configuration is preferable from the viewpoint of ensuring the support strength of the terminal portion by the metal support substrate.

[0010] The present invention [3] includes the wiring circuit board described in [2] above, wherein, in the projected view, the entirety of the second aperture periphery is located inside the terminal portion.

[0011] Such a configuration is preferable from the viewpoint of ensuring the support strength of the terminal portion by the metal support substrate.

[0012] The present invention [4] includes the wiring circuit board described in [1] above, wherein, in the projected view, the entirety of the first aperture peripheral edge is located outside the terminal portion.

[0013] Such a configuration is preferable from the viewpoint of securing a wide opening space for the opening.

[0014] The present invention [5] includes the wiring circuit board described in [2] or [4] above, wherein, in the projected view, the entirety of the second aperture periphery edge is located outside the terminal portion.

[0015] Such a configuration is preferable from the viewpoint of securing a wide opening space for the opening.

[0016] The present invention [6] includes the wiring circuit board described in [1] above, wherein the first opening peripheral edge includes a first portion located inside the terminal portion in the projected view and a second portion located outside the terminal portion in the projected view.

[0017] Such a configuration is preferable from the viewpoint of achieving both the securing of support strength for the terminal portion by the metal support substrate and the securing of opening space for the opening.

[0018] The present invention [7] includes the wiring circuit board described in [6] above, wherein the second opening edge includes a third portion that is located inside the terminal portion in the projected view and extends along the first portion.

[0019] Such a configuration is preferable from the viewpoint of ensuring the support strength of the terminal portion by the metal support substrate.

[0020] The present invention [8] includes the wiring circuit board described in [6] above, wherein the second opening edge includes a fourth portion that is located outside the terminal portion in the projected view and extends along the first portion.

[0021] Such a configuration is preferable from the viewpoint of ensuring a wide opening space for the opening.

[0022] The present invention [9] includes the wired circuit board according to any one of the above [1] to [8], wherein the conductor layer includes a plurality of the terminal portions, and the opening faces the plurality of terminal portions via the insulating layer.

[0023] Such a configuration is preferable from the viewpoint of increasing the density of the arrangement of the terminal portions.

[0024] The present invention

[10] includes the wired circuit board according to any one of the above [1] to [9], wherein the opening has a curved wall surface disposed between the first opening peripheral edge and the second opening peripheral edge and curved to bulge outward.

[0025] Such a configuration is suitable for ensuring a wide opening space for the opening.

[0026] The present invention

[11] includes the wired circuit board according to any one of the above [1] to

[10] , wherein a separation distance between the first opening peripheral edge and the second opening peripheral edge in the projection view is 20 µm or more and 120 µm or less.

[0027] Such a configuration is suitable for achieving both ensuring the supporting strength for the terminal portion and adjusting the characteristic impedance of the terminal portion.

[0028] The present invention

[12] includes the wired circuit board according to any one of the above [1] to

[11] , wherein the metal supporting substrate has a thickness of 20 µm or more and 250 µm or less.

[0029] Such a configuration is suitable for achieving both strength and flexibility in the metal supporting substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] [Figure 1]This is a partial plan view of a first embodiment of the wiring circuit board of the present invention. [Figure 2] Figure 1 is a plan view of one terminal and its vicinity in the wiring circuit board shown. [Figure 3] This is a cross-sectional view along line III-III in Figure 2. [Figure 4] This is a cross-sectional view along line IV-IV in Figure 2. [Figure 5] Figure 1 shows an example of a manufacturing method for a wiring circuit board. Figure 5A shows the base insulating layer formation process, Figure 5B shows the conductor layer formation process, Figure 5C shows the cover insulating layer formation process, and Figure 5D shows the opening formation process. [Figure 6] This is a partial cross-sectional view of a modified wiring circuit board shown in Figure 1. In this modified example, the opening of the metal support substrate has a shape that bulges outward in a longitudinal cross-sectional view. [Figure 7] This is a partial cross-sectional view of a modified wiring circuit board shown in Figure 1. In this modified example, the terminal section has a two-layer structure. [Figure 8] Figure 1 is a partial plan view of a modified wiring circuit board. In this modified example, in a projection view in the thickness direction, the entire first peripheral edge of the opening of the metal support substrate is located inside the terminal portion, and the entire second peripheral edge of the opening is located outside the terminal portion. [Figure 9] This is a cross-sectional view along the line IX-IX in Figure 8. [Figure 10] This is a cross-sectional view along line XX in Figure 8. [Figure 11] This is a partial plan view of a modified wiring circuit board shown in Figure 1. In this modified example, in a projection view in the thickness direction, the entirety of the first and second peripheral edges of the opening in the metal support substrate are located outside the terminal portion. [Figure 12] This is a cross-sectional view along the line XII-XII in Figure 11. [Figure 13] This is a cross-sectional view along the line XIII-XIII in Figure 11. [Figure 14]Figure 1 is a partial plan view of a modified wiring circuit board. In this modified version, the first peripheral edge of the opening of the metal support substrate includes a first portion located inside the terminal portion and a second portion located outside the terminal portion, as viewed in a thickness direction projection. In this modified version, the first portion extends in a first direction. [Figure 15] This is a cross-sectional view along the line XV-XV in Figure 14. [Figure 16] This is a cross-sectional view along the line XVI-XVI in Figure 14. [Figure 17] This is a partial plan view of a modified wiring circuit board shown in Figure 1. In this modified example, compared to the modified examples shown in Figures 14 to 16, the end of the terminal section opposite to the wiring connection side is located on the opening in a thickness direction projection view. [Figure 18] This is a partial plan view of a modified wiring circuit board shown in Figure 1. In this modified version, compared to the modified versions shown in Figures 14 to 16, the end of the terminal section opposite to the wiring connection side is located on the opening in a thickness direction projection view, and the opening is open in the plane direction. [Figure 19] Figure 1 is a partial plan view of a modified wiring circuit board. In this modified version, the first peripheral edge of the opening of the metal support substrate includes a first portion located inside the terminal portion and a second portion located outside the terminal portion, as viewed in a thickness direction projection. In this modified version, the first portion extends in the second direction. [Figure 20] This is a cross-sectional view along the line XX-XX in Figure 19. [Figure 21] This is a cross-sectional view along the line XXI-XXI in Figure 19. [Figure 22] This is a partial plan view of a second embodiment of the wiring circuit board of the present invention. [Figure 23] This is a cross-sectional view along the line XXIII-XXIII in Figure 22. [Figure 24] This is a cross-sectional view along the line XXIV-XXIV in Figure 22. [Figure 25]Figure 22 is a partial plan view of a modified wiring circuit board. In this modified example, the first peripheral edge of the opening of the metal support substrate includes a first portion located inside the terminal portion and a second portion located outside the terminal portion, when viewed in a thickness direction projection. [Figure 26] This is a cross-sectional view along the line XXVI-XXVI in Figure 25. [Figure 27] This is a cross-sectional view along the line XXVII-XXVII in Figure 25. [Figure 28] Figures 25 to 27 are partial plan views of modified wiring circuit boards. In these modified versions, compared to the modified version shown in Figure 25, the end of each terminal opposite to the wiring connection side is located on the opening in the thickness direction projection view. [Figure 29] Figures 25 to 27 are partial plan views of modified wiring circuit boards. In these modified versions, compared to the modified version shown in Figure 25, the end of each terminal opposite to the wiring connection side is located on an opening in a thickness direction projection view, and the opening is open in the plane direction. [Modes for carrying out the invention]

[0031] As shown in Figures 1 to 4, the wiring circuit board X1, as a first embodiment of the wiring circuit board of the present invention, comprises a metal support substrate 10, an insulating layer 20 as a base insulating layer, a conductor layer 30, and an insulating layer 40 as a cover insulating layer, in this order toward one side in the thickness direction T. The wiring circuit board X1 extends in a direction perpendicular to the thickness direction T (plane direction) and has a predetermined planar shape.

[0032] The metal support substrate 10 is a base material for ensuring the strength of the wiring circuit board X1. Examples of materials for the metal support substrate 10 include stainless steel, copper, copper alloy, aluminum, nickel, titanium, and 42 alloy. Examples of stainless steel include SUS304 based on the AISI (American Iron and Steel Institute) standard. From the viewpoint of strength of the metal support substrate 10, the metal support substrate 10 preferably comprises at least one selected from the group consisting of stainless steel, copper alloy, aluminum, nickel, and titanium, and more preferably consists of at least one selected from the group consisting of stainless steel, copper alloy, aluminum, nickel, and titanium. From the viewpoint of balancing strength and conductivity of the metal support substrate 10, the metal support substrate 10 is preferably made of a copper alloy.

[0033] The metal support substrate 10 has a plurality of openings 10A. Each of the plurality of openings 10A is formed to correspond to each of the plurality of terminal portions 31 described later. The openings 10A will be described in more detail later.

[0034] The thickness of the metal support substrate 10 is preferably 20 μm or more, more preferably 30 μm or more, even more preferably 40 μm or more, especially preferably 50 μm or more, and particularly preferably 60 μm or more. Such a configuration is preferable from the viewpoint of ensuring the strength of the metal support substrate 10. Alternatively, the thickness of the metal support substrate 10 is preferably 250 μm or less, more preferably 200 μm or less. Such a configuration is preferable from the viewpoint of ensuring the flexibility of the metal support substrate 10.

[0035] The insulating layer 20 is located on one side of the metal support substrate 10 in the thickness direction T. In this embodiment, the insulating layer 20 is located on one surface of the metal support substrate 10 in the thickness direction T. Examples of materials for the insulating layer 20 include resin materials such as polyimide, polyethernitrile, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, and polyvinyl chloride (similar resin materials can also be used for the insulating layer 40 described later). The thickness of the insulating layer 20 is preferably 1 μm or more, more preferably 3 μm or more, and preferably 35 μm or less, more preferably 20 μm or less.

[0036] The conductive layer 30 is located on one side of the metal support substrate 10 in the thickness direction T. In this embodiment, the conductive layer 30 is located on one surface of the metal support substrate 10 in the thickness direction T. Examples of materials for the conductive layer 30 include copper, nickel, gold, and alloys thereof, with copper being preferred. The thickness of the conductive layer 30 is, for example, 1 μm or more, preferably 3 μm or more. The thickness of the conductive layer 30 is, for example, 50 μm or less, preferably 30 μm or less.

[0037] The conductor layer 30 includes a plurality of terminal portions 31 and a plurality of wiring portions 32. The diagram illustrates an example in which three terminal portions 31 are arranged in a line spaced apart in a first direction D1, and the wiring portions 32 extend from one side of the terminal portions 31 in a second direction D2 (perpendicular to the first direction D1).

[0038] Examples of the plan view shape of the terminal portion 31 include a circle, a square, and a rounded square. Examples of squares include a square and a rectangle. Examples of rounded squares include a rounded square and a rounded rectangle (the case where the plan view shape of the terminal portion 31 is a rounded rectangle is illustrated as an example). The length L1 of the terminal portion 31 shown in Figure 2 (length in the first direction D1 of the terminal portion 31) is, for example, 10 to 1000 μm. The length L2 of the terminal portion 31 shown in Figure 2 (length in the second direction D2 of the terminal portion 31) is, for example, 10 to 1000 μm.

[0039] The wiring portion 32 has a predetermined pattern shape (not shown) on the insulating layer 20. One end of the wiring portion 32 is connected to a terminal portion 31 (in Figures 1 and 2, the portion of the wiring portion 32 covered by the insulating layer 40, described later, is shown by a dashed line). The other end of the wiring portion 32 is connected to another terminal portion 31, for example, not shown. The width of the wiring portion 32 (the dimension in the direction perpendicular to the extension direction of the wiring portion 32) is, for example, 5 μm or more, preferably 8 μm or more, and also, for example, 100 μm or less, preferably 50 μm or less.

[0040] The insulating layer 40 is arranged to cover a portion of the conductor layer 30 on one side of the insulating layer 20 in the thickness direction T. In this embodiment, the insulating layer 40 is arranged on one surface of the insulating layer 20 in the thickness direction T so as to cover a portion of the wiring portion 32. The thickness of the insulating layer 40 on the insulating layer 20 or on the wiring portion 32 is preferably 2 μm or more, more preferably 4 μm or more, and also preferably 60 μm or less, more preferably 40 μm or less.

[0041] In the metal support substrate 10, the opening 10A penetrates the metal support substrate 10 in the thickness direction T. The opening 10A faces one terminal portion 31 via the insulating layer 20. Examples of the plan view shape of the opening 10A include a circle, a square, and a rounded square. Examples of squares include squares and rectangles (the case where the plan view shape of the opening 10A is a rectangle is illustrated as an example). Examples of rounded squares include rounded squares and rounded rectangles. Preferably, the opening 10A has a plan view shape that is substantially the same as that of the terminal portion 31.

[0042] The opening 10A has a first opening edge 11 on one side in the thickness direction T, a second opening edge 12 on the other side in the thickness direction T, and an inner wall surface 13 between the first opening edge 11 and the second opening edge 12. As shown in Figures 3 and 4, the first opening edge 11 defines the first opening end 10a on one side (insulating layer 20 side) in the thickness direction T of the opening 10A. The second opening edge 12 defines the second opening end 10b on the other side in the thickness direction T of the opening 10A.

[0043] As shown in Figure 2, in a projection view in the thickness direction T, the second opening edge 12 is located outside the first opening edge 11 and extends along the first opening edge 11. In the opening 10A, the opening area of ​​the first opening end 10a is relatively small, and the opening area of ​​the second opening end 10b is relatively large. In this embodiment, as shown in Figures 3 and 4, the inner wall surface 13 is inclined such that the cross-sectional area of ​​the opening 10A gradually increases from the first opening edge 11 to the second opening edge 12. Furthermore, the separation distance d1 (shown in Figure 2) between the first opening edge 11 and the second opening edge 12 in the above projection view is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. The separation distance d1 is preferably 120 μm or less, more preferably 110 μm or less, and even more preferably 100 μm or less.

[0044] In this embodiment, in a projection view in the thickness direction T, the entirety of the first opening peripheral edge 11 is positioned inside the terminal portion 31, and the entirety of the second opening peripheral edge 12 is positioned inside the terminal portion 31. Such a configuration is preferable from the viewpoint of ensuring the support strength of the terminal portion 31 by the metal support substrate 10.

[0045] In this embodiment, the separation distance d2 (shown in Figure 2) between the edge of the terminal portion 31 and the first opening peripheral edge 11 in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d2 is preferably 400 μm or less, more preferably 300 μm or less. The ratio of the length L3 (length in the first direction D1) of the first opening end 10a shown in Figure 2 to the length L1 of the terminal portion 31 is preferably 0.3 or more and 0.98 or less. The ratio of the length L4 (length in the second direction D2) of the first opening end 10a shown in Figure 2 to the length L2 of the terminal portion 31 is preferably 0.3 or more and 0.98 or less. The ratio of the length L5 (length in the first direction D1) of the second opening end 10b shown in Figure 2 to the length L1 is preferably 0.31 or more and 0.99 or less. The ratio of the length L6 (length in the second direction D2) of the second open end 10b shown in Figure 2 to the length L2 is preferably 0.31 or more and 0.99 or less.

[0046] Figures 5A to 5D show an example of a manufacturing method for the wiring circuit board X1. Figures 5A to 5D represent this manufacturing method as a change in the cross-section corresponding to Figure 2.

[0047] In this manufacturing method, first, an insulating layer 20 is formed on one surface of the metal support substrate 10 in the thickness direction T, as shown in Figure 5A (base insulating layer formation step). In this step, the insulating layer 20 is formed, for example, as follows: First, a photosensitive resin solution (varnish) is applied to the metal support substrate 10 to form a coating film. Next, this coating film is dried by heating. Next, the coating film is subjected to exposure treatment through a predetermined mask, followed by development treatment, and then baking treatment as necessary. For example, the insulating layer 20 can be formed on the metal support substrate 10 in the manner described above.

[0048] Next, as shown in Figure 5B, a conductive layer 30 is formed on the insulating layer 20 (conductive layer formation step). In this step, first, a seed layer (not shown) is formed on the insulating layer 20, for example by sputtering. Examples of materials for the seed layer include Cr, Cu, Ni, Ti, and alloys thereof. The seed layer may have a single-layer structure or a multilayer structure of two or more layers. If the seed layer has a multilayer structure, it consists of, for example, a chromium layer as a lower layer and a copper layer on the chromium layer. Next, a resist pattern is formed on the seed layer. The resist pattern has openings with a shape corresponding to the pattern shape of the conductive layer 30. In forming the resist pattern, for example, a photosensitive resist film is bonded to the seed layer to form a resist film, and then the resist film is subjected to exposure treatment through a predetermined mask, followed by development treatment, and then baking treatment as necessary. In forming the conductive layer 30, the above-mentioned metal is then grown on the seed layer within the openings of the resist pattern, for example by electroplating. Next, the resist pattern is removed by etching. Then, the portion of the seed layer exposed by the removal of the resist pattern is removed by etching. For example, in this manner, a conductor layer 30 (terminal portion 31, wiring portion 32) with a predetermined pattern can be formed.

[0049] Next, as shown in Figure 5C, an insulating layer 40 is formed on the insulating layer 20 so as to cover a portion of the conductive layer 30 (cover insulating layer formation step). In this step, the insulating layer 40 is formed, for example, as follows: First, a photosensitive resin solution (varnish) is applied to the insulating layer 20 and the conductive layer 30 to form a coating film. Next, this coating film is dried. Next, the coating film is subjected to exposure treatment through a predetermined mask, followed by development treatment, and then baking treatment as necessary. For example, the insulating layer 40 can be formed in this manner.

[0050] Next, as shown in Figure 5D, an opening 10A is formed in the metal support substrate 10 (opening formation step). In this step, first, a resist pattern is formed on the other surface of the metal support substrate 10 in the thickness direction T. The resist pattern has an opening with a shape corresponding to the shape of the second opening peripheral edge 12 of the opening 10A described above. In forming the resist pattern, for example, a photosensitive resist film is bonded to the other surface of the metal support substrate 10 to form a resist film, and then the resist film is subjected to exposure treatment through a predetermined mask, followed by development treatment, and then baking treatment as necessary. In forming the opening 10A, next, wet etching is performed on the metal support substrate 10 from the other side in the thickness direction T using the resist pattern as an etching mask (etching treatment). Examples of etching solutions for wet etching include ferric chloride aqueous solution and cupric chloride solution. The concentration of the etching solution is, for example, 30 to 55% by mass. The temperature of the etching solution is, for example, 20°C to 55°C. The etching time is, for example, 1 to 15 minutes.

[0051] In this process, if necessary, the etching process described above is used to simultaneously form the opening 10A in the metal support substrate 10 and to process its outer shape.

[0052] In this manner, the wiring circuit board X1 can be manufactured.

[0053] In the wiring circuit board X1, as described above, an opening 10A facing the terminal portion 31 is formed in the metal support substrate 10 via an insulating layer 20. This configuration is suitable for adjusting the characteristic impedance of the terminal portion 31. In addition, in a projection view of the wiring circuit board X1 in the thickness direction T, the second opening edge 12 of the opening 10A is located outside the first opening edge 11 and extends along the first opening edge 11. That is, in the opening 10A, the first opening area at one end (terminal portion side) in the thickness direction T is relatively small, and the second opening area at the other end in the thickness direction T is relatively large. This configuration is suitable for adjusting the characteristic impedance of the terminal portion 31 by ensuring a wide opening space in the opening 10A while suppressing a decrease in the support strength of the terminal portion 31 by the metal support substrate 10. Therefore, the wiring circuit board X1 is suitable for adjusting the characteristic impedance of the terminal portion 31 while ensuring support strength for the terminal portion 13. Such technical effects can also be obtained in the modified examples and second embodiments described later.

[0054] In the wiring circuit board X1, as shown in Figures 2 and 3, the end portion 32a of the wiring portion 32 that connects to the terminal portion 31 is located on the metal support substrate 10, rather than on the first opening end 10a of the opening 10A, in a projection view in the thickness direction T. This configuration is suitable for preventing the end portion 32a of the wiring portion 31 from breaking when the terminals of external components (not shown) are joined to the terminal portion 31 during the mounting process of external components on the wiring circuit board X1. This technical effect can also be obtained in the modified examples shown in Figures 8 to 10, Figures 14 to 16, Figure 17, Figure 18, Figures 25 to 27, Figure 28, and Figure 29.

[0055] In the metal support substrate 10 of the wiring circuit board X1, the opening 10A may have a shape that bulges outward in a longitudinal cross-sectional view, as shown in Figure 6. That is, the inner wall surface 13 of the opening 10A may be a curved wall surface (curved surface) that curves outward (the center of curvature of the curved surface is located inside the opening 10A). Such a configuration is suitable for securing a wide opening space of the opening 10A while keeping the area of ​​the first opening end 10a of the opening 10A small.

[0056] To form such an opening 10A, as shown in Figure 5D, an aqueous ferric chloride solution is preferably used as the etching solution in the wet etching described above. The concentration of the etching solution is preferably 30% by mass or more, more preferably 32% by mass or more. The concentration of the etching solution is preferably 55% by mass or less, more preferably 53% by mass or less. The lower the concentration of the etching solution, the easier it is to widen the separation distance d1 between the first opening peripheral edge 11 and the second opening peripheral edge 12 in the projection view in the thickness direction T. The temperature of the etching solution is preferably 20°C or higher, more preferably 25°C or higher, and even more preferably 30°C or higher. The temperature of the etching solution is preferably 80°C or lower, more preferably 75°C or lower. The higher the temperature of the etching solution, the easier it is to curve the inner wall surface 13 (it is easier to reduce the radius of curvature of the inner wall surface 13). The etching time is preferably 1 minute or more, more preferably 2 minutes or more. The etching time is preferably 15 minutes or less, more preferably 12 minutes or less.

[0057] The terminal portion 31 on the wiring circuit board X1 may have a two-layer structure, as shown in Figure 7. Specifically, the terminal portion 31 shown in Figure 7 includes a first conductor layer 31A on the insulating layer 20 side and a second conductor layer 31B on the first conductor layer 31A.

[0058] The first conductor layer 31A is the same as the terminal portion 31 described above with reference to Figures 1 to 4. The second conductor layer 31B has an outer shape that fits within the outer shape of the first conductor layer 31A in a plan view. The thickness of the second conductor layer 31B is, for example, 1 μm or more, preferably 3 μm or more. The thickness of the second conductor layer 31B is, for example, 50 μm or less, preferably 30 μm or less. The material of the second conductor layer 31B is the same as the material described above for the conductor layer 30. The material of the first conductor layer 31A and the material of the second conductor layer 31B are preferably the same, and more preferably copper. The material of the first conductor layer 31A and the material of the second conductor layer 31B may be different.

[0059] A wiring circuit board X1 equipped with the terminal portion 31 shown in Figure 7 can be manufactured in the same manner as the above-described manufacturing method for the wiring circuit board X1, except that, for example, a second conductor layer 31B is patterned on the conductor layer 30 between the conductor layer formation step (Figure 5B) and the cover insulation layer formation step (Figure 5C).

[0060] Having a two-layer structure for the terminal portion 31 is preferable from the viewpoint of ensuring the strength of the terminal portion 31. The same applies to the modified examples and the second embodiment described later, in which the terminal portion 31 may have such a two-layer structure.

[0061] In the wiring circuit board X1, as shown in Figures 8 to 10, in a projection view in the thickness direction T, the entire first opening edge 11 of the opening 10A may be located inside the terminal portion 31, and the entire second opening edge 12 may be located outside the terminal portion 31. Such a configuration is preferable from the viewpoint of securing a wide opening space for the opening 10A.

[0062] In this modified example, the ratio of the length L3 of the first open end 10a shown in Figure 8 to the length L1 of the terminal portion 31 is preferably 0.4 or more and 0.98 or less. The ratio of the length L4 of the first open end 10a shown in Figure 8 to the length L2 of the terminal portion 31 is preferably 0.4 or more and 0.98 or less. The ratio of the length L5 of the second open end 10b shown in Figure 8 to the length L1 is preferably 1.01 or more and 3 or less. The ratio of the length L6 of the second open end 10b shown in Figure 8 to the length L2 is preferably 1.01 or more and 3 or less.

[0063] In the wiring circuit board X1, as shown in Figures 11 to 13, in a projection view in the thickness direction T, the entirety of the first opening edge 11 and the entirety of the second opening edge 12 of the opening 10A may be located outside the terminal portion 31. Such a configuration is preferable from the viewpoint of securing a wide opening space for the opening 10A.

[0064] In this modified example, the separation distance d2 (shown in Figure 11) between the edge of the terminal portion 31 and the first opening peripheral edge 11 in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d2 is preferably 400 μm or less, more preferably 300 μm or less. The ratio of the length L3 of the first opening end 10a shown in Figure 11 to the length L1 of the terminal portion 31 is preferably 1.01 or more and 4 or less. The ratio of the length L4 of the first opening end 10a shown in Figure 11 to the length L2 of the terminal portion 31 is preferably 1.01 or more and 4 or less. The ratio of the length L5 of the second opening end 10b shown in Figure 11 to the length L1 is preferably 1.05 or more and 5 or less. The ratio of the length L6 of the second opening end 10b shown in Figure 11 to the length L2 is preferably 1.05 or more and 5 or less.

[0065] In the wiring circuit board X1, as shown in Figures 14 to 16, the first opening edge 11 of the opening 10A may include a portion 11a (first portion) and a portion 11b (second portion). In a projection view in the thickness direction T, portion 11a is located inside the terminal portion 31, and portion 11b is located outside the terminal portion 31. Portion 11a extends in the first direction D1. Portion 11b includes a portion extending in the second direction D2 and a portion extending in the first direction D1. In a projection view in the thickness direction T, the second opening edge 12 includes a portion 12a (third portion) located inside the terminal portion 31 and extending along portion 11a, and a portion 12b located outside the terminal portion 31 and extending along portion 11b. The second opening edge 12 may include a portion 12a (fourth portion) that is located outside the terminal portion 31 and extends along portion 11a, and a portion 12b that is located outside the terminal portion 31 and extends along portion 11b. These configurations are preferable from the viewpoint of ensuring both the support strength of the terminal portion 31 by the metal support substrate 10 and the opening space of the opening 10A.

[0066] In this modified example, the separation distance d3 (shown in Figure 14) between the edge of the terminal portion 31 and portion 11a in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d3 is preferably 400 μm or less, more preferably 300 μm or less. The separation distance d4 (shown in Figure 14) between the edge of the terminal portion 31 and portion 11b in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d4 is preferably 400 μm or less, more preferably 300 μm or less. The ratio of the length L3 of the first open end 10a shown in Figure 14 to the length L1 of the terminal portion 31 is preferably 1.01 or more and 4 or less. The ratio of the length L4 of the first open end 10a shown in Figure 14 to the length L2 of the terminal portion 31 is preferably 0.31 or more and 0.99 or less. The ratio of the length L5 of the second open end 10b shown in Figure 14 to the length L1 is preferably 1.05 or more and 5 or less. The ratio of the length L6 of the second open end 10b shown in Figure 14 to the length L2 is preferably 0.31 or more and 0.99 or less.

[0067] In the modified examples shown in Figures 14 to 16, as shown in Figure 17, the end 31a of the terminal portion 31 opposite to the wiring portion 32 connection side may be located on the first opening end 10a of the opening 10A in a projection view in the thickness direction T.

[0068] In the modified example shown in Figure 17, if the location where the terminal portion 31 is formed is near the edge of the metal support substrate 10, the opening 10A may be open in the planar direction, as shown in Figure 18.

[0069] In the wiring circuit board X1, as shown in Figures 19 to 21, the first opening edge 11 of the opening 10A may include a portion 11c (first portion) and a portion 11d (second portion). In a projection view in the thickness direction T, portion 11c is located inside the terminal portion 31, and portion 11d is located outside the terminal portion 31. Portion 11c extends in the second direction D2. Portion 11d includes a portion extending in the first direction D1 and a portion extending in the second direction D2. In a projection view in the thickness direction T, the second opening edge 12 includes a portion 12c (third portion) located inside the terminal portion 31 and extending along portion 11c, and a portion 12d located outside the terminal portion 31 and extending along portion 11d. The second opening edge 12 may include a portion 12c (fourth portion) that is located outside the terminal portion 31 and extends along portion 11c, and a portion 12d that is located outside the terminal portion 31 and extends along portion 11d. These configurations are preferable from the viewpoint of ensuring both the support strength of the terminal portion 31 by the metal support substrate 10 and the opening space of the opening 10A.

[0070] In this modified example, the separation distance d5 (shown in Figure 19) between the edge of the terminal portion 31 and the portion 11c in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d5 is preferably 400 μm or less, more preferably 300 μm or less. The separation distance d6 (shown in Figure 19) between the edge of the terminal portion 31 and the portion 11d in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d6 is preferably 400 μm or less, more preferably 300 μm or less. The ratio of the length L3 of the first open end 10a shown in Figure 19 to the length L1 of the terminal portion 31 is preferably 0.31 or more and 0.99 or less. The ratio of the length L4 of the first open end 10a shown in Figure 19 to the length L2 of the terminal portion 31 is preferably 1.01 or more and 4 or less. The ratio of the length L5 of the second open end 10b shown in Figure 19 to the length L1 is preferably 0.31 or more and 0.99 or less. The ratio of the length L6 of the second open end 10b shown in Figure 19 to the length L2 is preferably 1.05 or more and 5 or less.

[0071] In the wiring circuit board X1 described above, instead of providing one opening 10A for each terminal portion 31, multiple openings (facing the terminal portion 31 via the insulating layer 20) may be provided for each terminal portion 31. The characteristic impedance of the terminal portion 31 may be adjusted by such a configuration.

[0072] Figures 22 to 24 show a wiring circuit board X2 as a second embodiment of the wiring circuit board of the present invention. Similar to the wiring circuit board X1, the wiring circuit board X2 comprises a metal support substrate 10, an insulating layer 20 as a base insulating layer, a conductor layer 30, and an insulating layer 40 as a cover insulating layer, in this order toward one side in the thickness direction T. The wiring circuit board X2 differs from the wiring circuit board X1 in that, instead of one opening 10A facing one terminal portion 31 via the insulating layer 20, one opening 10A faces multiple terminal portions 31 (arranged in a line spaced apart in the first direction D1) via the insulating layer 20. Other than this, the wiring circuit board X2 has the same configuration as the wiring circuit board X1.

[0073] As shown in Figure 22, in a projection view in the thickness direction T, the entirety of the first opening edge 11 and the entirety of the second opening edge 12 are positioned outside the terminal portion 31 in the opening 10A of the wiring circuit board X2. This configuration is preferable from the viewpoint of securing a wide opening space for the opening 10A.

[0074] In this embodiment, the separation distance d7 between the edge of the terminal portion 31 and the first opening peripheral edge 11 in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d7 is preferably 400 μm or less, more preferably 300 μm or less. The ratio of the length L4 of the first opening end 10a shown in Figure 22 to the length L2 of the terminal portion 31 is preferably 1.01 or more and 4 or less. The ratio of the length L6 of the second opening end 10b shown in Figure 22 to the length L2 is preferably 1.01 or more and 5 or less.

[0075] In the wiring circuit board X2, as shown in Figures 25 to 27, the first opening edge 11 of the opening 10A may include a portion 11a (first portion) and a portion 11b (second portion). In a projection view in the thickness direction T, portion 11a is located inside the terminal portion 31, and portion 11b is located outside the terminal portion 31. Portion 11a extends in a first direction D1. Portion 11b includes a portion extending in the first direction D1 and a portion extending in a second direction D2. In a projection view in the thickness direction T, the second opening edge 12 includes a portion 12a (third portion) located inside the terminal portion 31 and extending along portion 11a, and a portion 12b located outside the terminal portion 31 and extending along portion 11b. The second opening edge 12 may include a portion 12a (fourth portion) that is located outside the terminal portion 31 and extends along portion 11a, and a portion 12b that is located outside the terminal portion 31 and extends along portion 11b. These configurations are preferable from the viewpoint of ensuring both the support strength of the terminal portion 31 by the metal support substrate 10 and the opening space of the opening 10A.

[0076] In this modified example, the separation distance d8 (shown in Figure 25) between the edge of the terminal portion 31 and portion 11a in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d8 is preferably 400 μm or less, more preferably 300 μm or less. The separation distance d9 (shown in Figure 25) between the edge of the terminal portion 31 and portion 11b in the projected view is preferably 5 μm or more, more preferably 10 μm or more. The separation distance d9 is preferably 400 μm or less, more preferably 300 μm or less. The ratio of the length L4 of the first open end 10a shown in Figure 25 to the length L2 of the terminal portion 31 is preferably 0.31 or more and 0.99 or less. The ratio of the length L6 of the second open end 10b shown in Figure 25 to the length L2 is preferably 0.31 or more and 0.99 or less.

[0077] In the modified examples shown in Figures 25 to 27, as shown in Figure 28, the end portion 31a of each terminal portion 31 opposite to the wiring portion 32 connection side may be located on the first opening end 10a of the opening 10A in a projection view in the thickness direction T.

[0078] In the modified example shown in Figure 28, if the location where the terminal portion 31 is formed is near the edge of the metal support substrate 10, the opening 10A may be open in the planar direction, as shown in Figure 29. [Explanation of Symbols]

[0079] X1, X2 Wiring Circuit Board T (thickness direction) 10 Metal support substrate 10A opening 10a 1st open end 10b 2nd open end 11 First opening peripheral edge 12 Second opening peripheral edge 13 Interior wall surface 20,40 Insulating layer 30 Conductor Layers 31 Terminal section 32 Wiring section

Claims

1. The structure comprises a metal support substrate, an insulating layer, and a conductive layer, arranged in this order toward one side in the thickness direction. The conductor layer includes at least one terminal portion and a wiring portion extending from the terminal portion. The metal support substrate has an opening that penetrates the metal support substrate in the thickness direction and faces the terminal portion via the insulating layer, The opening has a first opening edge on one side in the thickness direction and a second opening edge on the other side in the thickness direction, and in a projection view in the thickness direction, the second opening edge is located outside the first opening edge and extends along the first opening edge. A wiring circuit board in which, in the projected view, at least a portion of the first opening edge is located inside the terminal portion, and at least a portion of the second opening edge is located outside the terminal portion.

2. The wiring circuit board according to claim 1, wherein the terminal portion includes a first conductor layer on the insulating layer side and a second conductor layer on the first conductor layer.

3. The structure comprises a metal support substrate, an insulating layer, and a conductive layer, arranged in this order toward one side in the thickness direction. The conductor layer includes at least one terminal portion and a wiring portion extending from the terminal portion. The metal support substrate has an opening that penetrates the metal support substrate in the thickness direction, The insulating layer is arranged between the terminal portion and the opening in the thickness direction. The entire other surface in the thickness direction of the terminal portion is in contact with the insulating layer. The opening has a first opening edge on one side in the thickness direction and a second opening edge on the other side in the thickness direction, and in a projection view in the thickness direction, the second opening edge is located outside the first opening edge and extends along the first opening edge. The terminal portion is a wiring circuit board that includes a first conductor layer on the insulating layer side and a second conductor layer on the first conductor layer.

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