Method for manufacturing a printed circuit board

Abstract

To provide a wiring circuit board manufacturing method suited for forming metal supporting parts at a fine pitch so as to correspond with wirings formed at a fine pitch.SOLUTION: A wiring circuit board manufacturing method of the present invention comprises the steps of: forming an isolation layer 20 on a surface on one side in a thickness direction of a substrate 60; forming a plurality of wirings 33 on a surface on one side in a thickness direction of the isolation layer 20; forming, in the substrate 60, an opening part 61 containing the plurality of wirings 33 therein in a thickness-direction projection view; forming, on a surface on the other side in the thickness direction of the isolation layer 20, a resist pattern 80 having opening parts 81a having a pattern shape corresponding to the plurality of wirings 33; forming metal supporting parts 12 by depositing a metal material 12a on the isolation layer 20 in the opening parts 81a; and removing the resist pattern 80.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a wired circuit board. [Background technology]

[0002] A wired circuit board is known that includes a metal supporting substrate, an insulating layer on the metal supporting substrate, and a plurality of wirings on the insulating layer. In the wired circuit board, in order to enhance heat dissipation from the metal supporting substrate side, for example, the metal supporting substrate is patterned to have a shape along the wirings, thereby increasing the surface area of ​​the metal supporting substrate. A method for manufacturing such a wired circuit board is described, for example, in Patent Document 1 below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-212659 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the method for manufacturing a wired circuit board described in Patent Document 1, the metal supporting substrate is patterned as follows. First, a resist pattern is formed on both sides in the thickness direction of the metal supporting substrate on which an insulating layer of a predetermined pattern and wiring on the insulating layer are formed. The resist pattern masks the parts of the metal supporting substrate that are to be left. Next, an etching solution is sprayed onto the metal supporting substrate from one or both sides in the thickness direction. The etching solution corrodes the metal supporting substrate and removes the corroded parts (wet etching). By such wet etching process, the metal supporting substrate is patterned, and metal supporting parts along the wiring are formed for each wiring.

[0005] The openings in the resist pattern used in the wet etching process must be wide enough to allow the required amount of etching solution to pass through.

[0006] In addition, in the wet etching process, the etching of the metal supporting substrate by the etching solution proceeds not only in the thickness direction of the substrate, but also in the surface direction perpendicular to the thickness direction, albeit at a slower rate. Therefore, even if the metal supporting substrate is masked by the resist pattern when projected in the thickness direction, some parts are removed (the formation of undercuts). The mask width of the resist pattern in the part of the metal supporting substrate where the metal supporting part is to be formed needs to be wider than the metal supporting part to be formed by the length of the undercut.

[0007] In addition, the thicker the metal supporting substrate, the longer it takes to wet etch the substrate and therefore the longer the undercut that is formed, so the thicker the metal supporting substrate, the wider the resist pattern needs to be.

[0008] The design arrangement of adjacent metal supporting parts after patterning is determined taking into consideration the width of the opening in the resist pattern and the length of the undercut. The distance between adjacent metal supporting parts needs to be sufficiently long so that the width of the opening and the length of the undercut are secured. Such a method for manufacturing a wiring circuit board is not suitable for patterning a metal supporting base material at a fine pitch in response to wiring formed at a fine pitch.

[0009] The present invention provides a method for manufacturing a wired circuit board suitable for forming metal supporting parts at a fine pitch in correspondence with wiring formed at a fine pitch. [Means for solving the problem]

[0010] The present invention [1] includes a method for manufacturing a wired circuit board, including a first step of forming an insulating layer on one thickness-wise surface of a substrate, a second step of forming a plurality of wirings on one thickness-wise surface of the insulating layer, a third step of forming a first opening in the substrate, the first opening including the plurality of wirings when projected in the thickness direction, a fourth step of forming a resist pattern on the other thickness-wise surface of the insulating layer, the resist pattern having a second opening having a pattern shape following the plurality of wirings, a fifth step of depositing a metal material on the other thickness-wise surface of the insulating layer within the second opening to form a metal support portion, and a sixth step of removing the resist pattern.

[0011] In the method for producing a wired circuit board of the present invention, as described above, after the first opening is formed in the substrate in the third step, the metal support portion that supports the wiring is formed through the fourth and fifth steps. In the fifth step, the metal support portion along the wiring is formed by depositing a metal material in the second opening of the resist pattern. Therefore, the arrangement of adjacent metal support portions depends on the arrangement of the second opening formed in the resist pattern. Since the resist pattern can be patterned by photolithography technology, it is easy to form openings at a fine pitch in such a resist pattern. In addition, in this production method, since the metal support portion is not formed by wet etching the metal supporting substrate, it is not necessary to consider the width of the opening of the resist pattern and the length of the undercut with respect to the arrangement of the metal support portion, unlike the conventional production method described above. Such a production method of the present invention is suitable for forming a metal support portion at a fine pitch corresponding to wiring formed at a fine pitch.

[0012] The present invention [2] includes the method for producing a wired circuit board described above in [1], further comprising a seventh step of forming a third opening in the insulating layer between adjacent wires after the sixth step.

[0013] Such a configuration is preferable for ensuring the surface area of ​​the insulating layer in the vicinity of the wiring and for improving the heat dissipation of the wiring.

[0014] The present invention [3] includes the method for manufacturing the wired circuit board described in [2] above, wherein the insulating layer has a thick portion and a thin portion, and in the second step, the wiring is formed on the thick portion, and in the seventh step, the thin portion is removed by etching the insulating layer from the other side in the thickness direction to form the third opening.

[0015] Such a configuration is preferable for appropriately forming the above-mentioned third opening in the insulating layer between adjacent wirings.

[0016] The present invention [4] includes the method for producing a wired circuit board according to any one of the above [1] to [3], wherein the metal supporting portion has a thickness of 20 μm or more and 300 μm or less.

[0017] Such a configuration is preferable for achieving both supporting strength and heat dissipation properties in the metal supporting portion. [Brief description of the drawings]

[0018] [Figure 1] 1 is a plan view of a printed circuit board manufactured by one embodiment of a method for manufacturing a printed circuit board according to the present invention. [Diagram 2] FIG. 2 is a bottom view of the printed circuit board shown in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] 2 is a cross-sectional view taken along line VV in FIG. 1. [Figure 6] 6A, 6B, and 6C are process diagrams of one embodiment of a method for producing a wired circuit board according to the present invention, in which Fig. 6A shows a base insulating layer forming process, Fig. 6B shows a conductor layer forming process, and Fig. 6C shows a cover insulating layer forming process. [Figure 7] 7A and 7B show the steps following the step shown in Fig. 6. Fig. 7A shows the first resist pattern forming step, Fig. 7B shows the substrate patterning step, and Fig. 7C shows the first resist pattern removing step. [Figure 8]8A shows a process subsequent to the process shown in Fig. 7. Fig. 8A shows a second resist pattern forming process, Fig. 8B shows a metal support layer forming process, and Fig. 8C shows a second resist pattern removing process. [Figure 9] 9A and 9B show the steps subsequent to the step shown in Fig. 8. Fig. 9A shows the protective film forming step, Fig. 9B shows the base insulating layer patterning step, and Fig. 9C shows the protective film removing step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] 1 to 5 show a wired circuit board X manufactured by one embodiment of the wired circuit board manufacturing method of the present invention. The wired circuit board X includes a metal support layer 10, an insulating layer 20 as a base insulating layer, a conductor layer 30, and an insulating layer 40 as a cover insulating layer, which are arranged in this order in a thickness direction T. The wired circuit board X extends in a direction (plane direction) perpendicular to the thickness direction T, and has a predetermined shape in a plan view. The shape of the wired circuit board X shown in Figs. 1 and 2 in a plan view is an exemplary shape.

[0020] The metal supporting layer 10 is a portion for ensuring the strength of the wiring circuit board X. The metal supporting layer 10 has a predetermined pattern shape and includes a plurality of land portions 11 and a plurality of metal supporting portions 12. A case in which the metal supporting layer 10 includes two land portions 11 and four metal supporting portions 12 is shown as an example.

[0021] The two land portions 11 (land portion 11A, land portion 11B) are spaced apart in the first direction D1. The land portion 11A is disposed at one end of the wiring circuit board X in the first direction D1. The land portion 11B is disposed at the other end of the wiring circuit board X in the first direction D1. Each land portion 11 has a predetermined shape in a plan view. A case in which the shape of the land portion 11 in a plan view is rectangular is shown as an example. The thickness of the land portion 11 is preferably 20 μm or more, more preferably 50 μm or more, even more preferably 80 μm or more, and is preferably 300 μm or less, more preferably 250 μm or less. The thickness of the land portion 11 may be the same as or different from the thickness of the metal support portion 12.

[0022] The multiple metal supporting portions 12 are portions that support wiring 33, which will be described later, and extend from land portion 11A to land portion 11B. An example is shown in which each metal supporting portion 12 extends linearly in a first direction D1 between land portions 11A and 11B. One end of each metal supporting portion 12 in the first direction D1 is connected to land portion 11A. The other end of each metal supporting portion 12 in the first direction D1 is connected to land portion 11B. The length (total length) of each metal supporting portion 12 from land portion 11A to land portion 11B is, for example, 5 to 40 mm.

[0023] The metal support parts 12 are arranged apart from each other in the second direction D2. The second direction D2 is perpendicular to the thickness direction T and the first direction D1. The width W1 (length in the second direction D2) of the metal support parts 12 is, for example, 10 μm or more, preferably 15 μm or more. The width W1 is, for example, 100 μm or less, preferably 50 μm or less. The separation distance d1 between adjacent metal support parts 12 is, for example, 50 μm or more, preferably 80 μm or more. The separation distance d1 is, for example, 300 μm or less, preferably 150 μm or less. The ratio (d1 / W1) of the separation distance d1 to the width W1 of the metal support part 12 is, for example, 0.5 or more, preferably 1.2 or more. The ratio (d1 / W1) is, for example, 30 or less, preferably 5 or less.

[0024] The thickness H1 of the metal supporting part 12 is preferably 20 μm or more, more preferably 80 μm or more. The thickness H1 of the metal supporting part 12 is preferably 300 μm or less, more preferably 250 μm or less. The ratio (H1 / W1) of the thickness H1 to the width W1 of the metal supporting part 12 is, for example, 0.2 or more, preferably 1.0 or more. The ratio (H1 / W1) is, for example, 30 or less, preferably 5 or less. These configurations are preferable for the metal supporting part 12 to achieve both supporting strength and heat dissipation. The ratio (H1 / H2) of the thickness H1 of the metal supporting part 12 to the thickness H2 of the wiring 33 described later is, for example, 0.4 or more, preferably 3.0 or more. The ratio (H1 / H2) is, for example, 100 or less, preferably 25 or less.

[0025] Examples of materials for the metal support layer 10 include copper, copper alloy, aluminum, nickel, titanium, and alloy 42. From the viewpoint of the strength of the metal support layer 10, the metal support layer 10 preferably includes at least one selected from the group consisting of copper, copper alloy, aluminum, nickel, and titanium, and more preferably is made of at least one selected from the group consisting of copper, copper alloy, aluminum, nickel, and titanium. From the viewpoint of achieving both strength and flexibility of the metal support layer 10, the metal support layer 10 is preferably made of copper or a copper alloy.

[0026] The insulating layer 20 is disposed on one side of the metal support layer 10 in the thickness direction T. In this embodiment, the insulating layer 20 is disposed on one surface of the metal support layer 10 in the thickness direction T. The insulating layer 20 includes a plurality of first portions 21 and a plurality of second portions 22, and has a predetermined pattern shape. A case in which the insulating layer 20 includes two first portions 21 (first portion 21A, first portion 21B) and four second portions 22 is illustrated as an example.

[0027] As shown in Figs. 1 and 3, the first portion 21A is disposed on the land portion 11A of the metal support layer 10. As shown in Figs. 1 and 4, the first portion 21B is disposed on the land portion 11B. Each of the first portions 21 has a predetermined shape in plan view. A case in which the shape of the first portion 21 in plan view is rectangular is shown as an example. The thickness of the first portion 21 is preferably 1 µm or more, more preferably 3 µm or more, and is preferably 35 µm or less, more preferably 20 µm or less.

[0028] The second portion 22 is disposed along each metal support 12 for each metal support 12, and extends from the first portion 21A to the first portion 21B. The multiple portions 22 are disposed corresponding to the multiple metal support portions 12, and are spaced apart from each other in the second direction D2. One end of each second portion 22 in the first direction D1 is connected to the first portion 21A. The other end of each second portion 22 in the first direction D1 is connected to the first portion 21B.

[0029] As shown in FIG. 5, the second portion 22 has a thick portion 22a and a thin portion 22b thinner than the thick portion 22a. The thick portion 22a is disposed on the metal support portion 12. The thin portion 22b is disposed on each of both sides of the thick portion 22a in the second direction D2. The thickness H3 of the thick portion 22a is preferably 1 μm or more, more preferably 3 μm or more, and preferably 35 μm or less, and more preferably 20 μm or less. The thickness H4 of the thin portion 22b is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably less than 35 μm, and more preferably 20 μm or less, as long as it is thinner than the thick portion 22a. The ratio (H4 / H3) of the thickness H4 to the thickness H3 is preferably 0.1 or more, more preferably 0.2 or more, and preferably less than 1, and more preferably 0.9 or less.

[0030] Examples of materials for the insulating layer 20 include resin materials such as polyimide, polyethernitrile, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, and polyvinyl chloride, and polyimide is preferably used (the same applies to the material for the insulating layer 40 described below).

[0031] The conductor layer 30 is disposed on one side of the insulating layer 20 in the thickness direction T. In this embodiment, the conductor layer 30 is disposed on one surface of the insulating layer 20 in the thickness direction T. The conductor layer 30 includes a plurality of first terminal portions 31, a plurality of second terminal portions 32, and a plurality of wirings 33, and has a predetermined pattern shape.

[0032] The first terminal portion 31 is disposed on the first portion 21A. The first terminal portions 31 are disposed at intervals in the second direction D2. The second terminal portions 32 are disposed on the first portion 21B. The second terminal portions 32 are disposed at intervals in the second direction D2. The planar shape of the first terminal portion 31 and the planar shape of the second terminal portion 32 are wider than the wiring 33 in the second direction D2. Examples of the planar shapes of the terminal portions 31 and 32 include a circle, a rectangle, and a rounded rectangle. Examples of the rectangle include a square and a rectangle. Examples of the rounded rectangle include a square with rounded corners and a rounded rectangle. An example of a case in which the planar shape of the terminal portions 32 and 33 is a rectangle is illustrated.

[0033] The wiring 33 is disposed on the first portion 21A, the second portion 22, and the first portion 21B of the insulating layer 20, and extends in a first direction D1. The multiple wirings 33 are disposed corresponding to the multiple second portions 22, and are spaced apart from each other in the second direction D2. One end of each wiring 33 in the first direction D1 is connected to the first terminal 31. The other end of each wiring 33 in the first direction D1 is connected to the second terminal 32.

[0034] The width W2 of the wiring 33 (length in the second direction D2) is, for example, 10 μm or more, preferably 20 μm or more. The width W2 is, for example, 80 μm or less, preferably 50 μm or less. The ratio (W2 / W1) of the width W2 of the wiring 33 to the width W1 of the metal support part 12 described above is, for example, 0.1 or more, preferably 0.3 or more. The ratio (W2 / W1) is, for example, 4 or less, preferably 2 or less.

[0035] The separation distance d2 between adjacent wirings 33 is, for example, 50 μm or more, preferably 80 μm or more. The separation distance d2 is, for example, 300 μm or less, preferably 150 μm or less. The ratio (d2 / W2) of the separation distance d2 to the width W2 of the wiring 33 is, for example, 0.6 or more, preferably 1 or more. The ratio (d2 / W2) is, for example, 30 or less, preferably 7.5 or less.

[0036] Examples of materials for the conductor layer 30 include copper, nickel, gold, and alloys thereof, and copper is preferably used. The thickness of the conductor layer 30 is, for example, 3 μm or more, and preferably 5 μm or more. The thickness of the conductor layer 30 is, for example, 50 μm or less, and preferably 30 μm or less.

[0037] The insulating layer 40 is disposed so as to cover the conductor layer 30 on one side in the thickness direction T of the insulating layer 20. In this embodiment, the insulating layer 40 is disposed on one surface in the thickness direction T of the insulating layer 20 so as to cover the wiring 33. The thickness of the insulating layer 40 on the insulating layer 20 and on the wiring 33 is preferably 2 μm or more, more preferably 4 μm or more, and is preferably 60 μm or less, more preferably 40 μm or less.

[0038] Figures 6 to 9 show one embodiment of the method for producing a wired circuit board of the present invention. Figures 6 to 9 show this production method as changes in a cross section corresponding to Figure 5. In this embodiment, this production method includes a base insulating layer forming step, a conductor layer forming step, a cover insulating layer forming step, a first resist pattern forming step, a substrate patterning step, a first resist pattern removing step, a second resist pattern forming step, a metal support layer forming step, a second resist pattern removing step, a protective film forming step, a base insulating layer patterning step, and a protective film removing step.

[0039] In this manufacturing method, first, as shown in FIG. 6A, an insulating layer 20A is formed on one surface of a substrate 60 in a thickness direction T (a base insulating layer forming step).

[0040] A metal substrate is preferably used as the substrate 60. Examples of the material of the metal substrate include stainless steel, copper, copper alloy, nickel, titanium, and 42 alloy. Examples of stainless steel include SUS304 based on the standard of AISI (American Iron and Steel Institute). The thickness of the substrate 60 is, for example, 10 to 50 μm.

[0041] The insulating layer 20A includes a relatively thick first region 20a (thick portion) and a relatively thin second region 20b (thin portion). The first region 20a is a portion of the insulating layer 20A that remains in a patterning step (shown in FIG. 9B) to be described later and becomes the insulating layer 20.

[0042] In this step, the insulating layer 20A is formed, for example, as follows. First, a solution (varnish) of a positive photosensitive resin is applied onto the substrate 60 to form a coating film. Next, the coating film is dried by heating. Next, the coating film is subjected to an exposure process through a predetermined mask, a subsequent development process, and then a baking process as necessary. In the exposure process, the amount of exposure is relatively small for the area where the first region 20a is to be formed, and relatively large for the area where the second region 20b is to be formed. This allows the insulating layer 20A including the first region 20a and the second region 20b to be formed in this step. This step corresponds to the first step of the present invention.

[0043] Next, as shown in FIG. 6B, the above-mentioned conductor layer 30 is formed on the first region 20a of the insulating layer 20A (conductor layer forming step). In this step, a first seed layer (not shown) is first formed on the insulating layer 20A by, for example, a sputtering method. 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 multi-layer structure of two or more layers. When the seed layer has a multi-layer structure, the seed layer is made 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 an opening having a shape corresponding to the pattern shape of the conductor layer 30. In forming the resist pattern, for example, a photosensitive resist film is attached on the seed layer to form a resist film, and then the resist film is subjected to an exposure process through a predetermined mask, a development process, and then a baking process as necessary. In forming the conductor layer 30, the metal described above for the conductor layer 30 is then grown on the seed layer in the openings of the resist pattern by electrolytic plating. The resist pattern is then removed by etching. The portions of the seed layer exposed by removing the resist pattern are then removed by etching. For example, in this manner, the conductor layer 30 (first terminal portion 31, second terminal portion 32, wiring 33) having a predetermined pattern is formed on the first region 20a. This process corresponds to the second process of the present invention.

[0044] Next, as shown in FIG. 6C, an insulating layer 40 is formed on the insulating layer 20A so as to cover the conductor layer 30 (cover insulating layer forming process). In this process, a photosensitive resin solution (varnish) is first applied onto the insulating layer 20A and the conductor layer 30 to form a coating film. Next, this coating film is dried. Next, the coating film is exposed to light through a predetermined mask, then developed, and then baked as necessary. For example, in the manner described above, an insulating layer 40 having a predetermined pattern can be formed.

[0045] Next, as shown in FIG. 7A, a resist pattern 70 is formed on the other surface of the substrate 60 in the thickness direction T (first resist pattern forming step). The resist pattern 70 has an opening 71 and has a frame shape that masks the peripheral portion of the substrate 60 in a plan view. The opening 71 has a shape that encompasses the wiring circuit board X described above in a thickness direction projection view. In forming the resist pattern 70, for example, a photosensitive resist film is attached to the other surface of the substrate 60 in the thickness direction T to form a resist film, and then the resist film is subjected to an exposure process through a predetermined mask, a development process, and a bake process as necessary (the same applies to a method for forming a resist pattern 80 described later).

[0046] Next, as shown in FIG. 7B, an opening 61 (first opening) is formed in the substrate 60 (substrate patterning step). In this step, the substrate 60 is wet-etched from the other side in the thickness direction T using the resist pattern 70 as an etching mask. Examples of the etching solution for wet etching include an aqueous ferric chloride solution and a cupric chloride solution. The concentration of the etching solution is, for example, 30 to 55 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. The opening 61 thus formed has a shape that includes the above-mentioned wiring circuit board X when projected in the thickness direction. That is, the opening 61 has a shape that includes the above-mentioned multiple wirings 33 when projected in the thickness direction. This step corresponds to the third step of the present invention. After this step, in this embodiment, a second seed layer (not shown) is formed on the other surface in the thickness direction T of the insulating layer 20A by, for example, a sputtering method. The material and layer structure of the second seed layer are the same as those of the first seed layer described above with reference to FIG. 6B.

[0047] Next, as shown in FIG. 7C, the resist pattern 70 is removed (first resist pattern removing step).

[0048] Next, as shown in FIG. 8A, a resist pattern 80 is formed on the other surface of the insulating layer 20A in the thickness direction T (second resist pattern formation step). The resist pattern 80 has openings 81. In a plan view, the openings 81 have a pattern shape corresponding to the above-mentioned conductor layer 30. The openings 81 include openings 81a (second openings) having a pattern shape along the multiple wirings 33 in a thickness direction projection view. This step corresponds to the fourth step of the present invention.

[0049] Next, as shown in FIG. 8B, a metal material 12a is deposited on the other surface of the insulating layer 20A in the thickness direction T within the opening 81 to form the above-mentioned metal support layer 10 (metal support layer formation process). Specifically, in this process, the metal material 12a is grown on the seed layer within the opening 81 of the resist pattern 80 by electrolytic plating. This forms the metal support layer 10 within the opening 81. Within the opening 81a, a metal support portion 12 is formed by the deposition of the metal material 12a. This process corresponds to the fifth process of the present invention.

[0050] Next, as shown in Fig. 8C, the resist pattern 80 is removed (second resist pattern removal step). This step corresponds to the sixth step of the present invention. After removing the resist pattern 80, the portion of the second seed layer exposed by removing the resist pattern is removed by etching.

[0051] 9A, a protective film 90 that covers the conductor layer 30 and the cover insulating layer 40 is formed on one side of the insulating layer 20A in the thickness direction T (protective film forming process). As the protective film 90, for example, a dry film resist can be used.

[0052] Next, as shown in Fig. 9B, the insulating layer 20A is patterned (base insulating layer patterning step). In this step, the second region 20b of the insulating layer 20A is removed by wet etching from the other side in the thickness direction T of the insulating layer 20A to form an opening 20c (third opening). As a result, the insulating layer 20 described above is formed, and the wiring circuit board X held by the frame-shaped base material 70 via the protective film 90 is obtained. This step corresponds to the seventh step of the present invention.

[0053] Next, as shown in Fig. 9C, the protective film 90 is removed (protective film removing step). By removing the protective film 90, the wired circuit board X is isolated. In this manner, the wired circuit board X is manufactured.

[0054] In the above-mentioned method for manufacturing a wired circuit board, in the conductor layer forming step (FIG. 6B), the metal material 12a is deposited in the openings 81a of the resist pattern 80 to form the metal support parts 12 along the wiring 33. Therefore, the arrangement of adjacent metal support parts 12 depends on the arrangement of the openings 81a formed in the resist pattern 80. Since the resist pattern can be patterned by photolithography technology, it is easy to form openings at a fine pitch in such a resist pattern. In addition, in this manufacturing method, since the metal support parts 12 are not formed by wet etching the metal support base material, it is not necessary to consider the width of the openings of the resist pattern and the length of the undercut regarding the arrangement of the metal support parts 12. Such a manufacturing method of the present invention is suitable for forming metal support parts at a fine pitch corresponding to wiring formed at a fine pitch. The width W1 of the metal support portion 12, the separation distance d1 between adjacent metal support portions 12, the ratio (d1 / W1) of the separation distance d1 to the width W1, and the ratio (H1 / W1) of the thickness H1 of the metal support portion 12 to the width W1 are as described above.

[0055] As described above, the present manufacturing method includes a base insulating layer patterning step (FIG. 9B) of forming openings 20c in the insulating layer 20A between adjacent wirings 33. Such a configuration is preferable for ensuring the surface area of ​​the insulating layer 20 near the wiring 33 and enhancing the heat dissipation of the wiring 33.

[0056] In this manufacturing method, the insulating layer 20A formed in the base insulating layer forming step (FIG. 6A) has a first region 20a (thick portion) and a second region 20b (thin portion), the wiring 33 is formed on the first region 20a in the conductor layer forming step (FIG. 6B), and the second region 20b (thin portion) is removed by etching the insulating layer 20A from the other side in the thickness direction to form the opening 20c in the insulating layer 20A in the base insulating layer patterning step (FIG. 9B). Such a configuration is preferable for appropriately forming the opening 20c in the insulating layer 20A between adjacent wirings 33. [Explanation of symbols]

[0057] X Wiring Circuit Board D1 1st direction D2 2nd direction T thickness direction 10 Metal support layer 11 Land Department 12 Metal support part 12a Metal materials 20,40 Insulating layer 20A Insulation Layer 20a 1st area (thick wall part) 20b 2nd area (thin part) 21 Part 1 22 Part 2 22a Thick wall part 22b Thin wall part 30 Conductor Layer 33 Wiring 60 Base material 61 Opening (First Opening) 80 Resist Pattern 81 Opening (Second Opening)

Claims

1. A first step of forming an insulating layer on one surface in a thickness direction of a substrate; a second step of forming a plurality of wirings on one surface in a thickness direction of the insulating layer; A third step of forming a first opening in the base material, the first opening including the plurality of wirings when projected in a thickness direction; a fourth step of forming a resist pattern having second openings having a pattern shape along the plurality of wirings on the other surface of the insulating layer in the thickness direction within the first openings; a fifth step of depositing a metal material on the other surface in the thickness direction of the insulating layer within the second opening to form a metal supporting portion; and a sixth step of removing the resist pattern.

2. 2. The method for producing a wired circuit board according to claim 1, further comprising a seventh step of forming a third opening in the insulating layer between adjacent ones of the wirings after the sixth step.

3. 3. The method for manufacturing a wired circuit board according to claim 2, wherein the insulating layer has a thick portion and a thin portion, the second step forms the wiring on the thick portion, and the seventh step forms the third opening by removing the thin portion through an etching process from the other side in a thickness direction of the insulating layer.

4. The method for producing a wired circuit board according to claim 1 , wherein the metal supporting portion has a thickness of 20 μm or more and 300 μm or less.

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