Metal-clad laminate and circuit board, and method for producing them

Abstract

To provide a metal-clad laminate having excellent adhesion between a resin film and a metal layer, a circuit board and a method for producing them.SOLUTION: A metal-clad laminate has a resin film, and a metal layer laminated on at least one surface of the resin film, which is termed the metal layer laminate face, without an adhesive interposed therebetween. The 180° peeling strength of the metal layer and the resin film is 0.6 N / mm or more.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to a metal-clad laminate, a wiring board, a method for manufacturing a metal-clad laminate, and a method for manufacturing a wiring board. [Background technology]

[0002] In recent years, with the increasing functionality of electronic devices and the increasing frequency of signals processed by electronic devices, etc., there has been a demand for flexible wiring boards, etc. that can exhibit excellent high-frequency characteristics, and metal-clad laminates, etc. that can be used to manufacture such flexible wiring boards, etc. Among such flexible wiring boards, etc., flexible wiring boards that use a cycloolefin polymer film as a substrate and metal-clad laminates that use a cycloolefin polymer film have been proposed from the perspective of having excellent high-frequency characteristics.

[0003] Conventionally, such metal-clad laminates have been known to have a base metal layer containing nickel, chromium, etc. formed on the surface of a cycloolefin polymer film, and a copper layer formed on the surface of the base metal layer (see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6299226 Summary of the Invention [Problem to be solved by the invention]

[0005] The metal-clad laminate described in Patent Document 1 has a metal layer (base metal layer and copper layer) formed on the surface of a cycloolefin polymer film without the use of an adhesive. In a metal-clad laminate, the adhesion between the polymer film (resin film) and the metal layer is an important factor in determining the reliability of a flexible wiring board manufactured from the metal-clad laminate. However, if the polymer film and the metal layer are bonded together with an adhesive to improve the adhesion between them, the presence of the adhesive adhesive layer will degrade the high-frequency characteristics. In the metal-clad laminate described in Patent Document 1, the metal layer is formed on the surface of the cycloolefin polymer film without the use of an adhesive, which can prevent the high-frequency characteristics from deteriorating due to the presence of the adhesive adhesive layer. However, there is a problem in that the adhesion between the cycloolefin polymer film and the metal layer is insufficient.

[0006] In view of the above problems, an object of the present disclosure is to provide a metal-clad laminate and a wiring board having excellent adhesion between a resin film and a metal layer, and methods for manufacturing the same. [Means for solving the problem]

[0007] In order to solve the above problems, one embodiment of the present disclosure provides a metal-clad laminate comprising a resin film and a metal layer laminated without an adhesive on at least one surface of the resin film, which is the metal layer lamination surface, and wherein the 180° peel strength between the metal layer and the resin film is 0.6 N / mm or more.

[0008] The root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the metal layer laminated surface exposed after the metal layer is removed may both be 50 nm or less, and the haze of the resin film after the metal layer is removed may be 1.0 or less. The resin film may further include an underlayer formed between the metal layer and the metal layer laminated surface, and the underlayer may be an indium zinc oxide (IZO) thin film. The resin film may further include a bonding layer formed between the metal layer and the metal layer laminated surface and composed of a molecular bonding agent. The resin film may be a cycloolefin polymer film, and both surfaces of the resin film may be the metal layer laminated surfaces, and the metal layer may be laminated on each of the two metal layer laminated surfaces without the adhesive.

[0009] A pattern having recesses and protrusions may be formed on the metal layer lamination surface of the resin film, and the metal layer may be laminated so as to fill the recesses and cover the metal layer lamination surface.

[0010] One embodiment of the present disclosure provides a wiring board including a wiring layer formed by etching the metal layer of the metal-clad laminate.

[0011] As one embodiment of the present disclosure, a wiring board is provided having a wiring layer formed as a portion embedded in the recess by removing the metal layer so as to expose the top of the convex portion of the pattern of the metal-clad laminate.

[0012] As one embodiment of the present disclosure, there is provided a wiring board manufactured from the above-mentioned metal-clad laminate and having a wiring layer, wherein the wiring layer has a laminated structure of at least two layers, one of the two layers constituting the wiring layer is a layer formed by etching the metal layer of the metal-clad laminate, and the other of the two layers constituting the wiring layer is a layer laminated on top of the layer formed by etching the metal layer of the metal-clad laminate.

[0013] As one embodiment of the present disclosure, there is provided a method for producing a metal-clad laminate in which a metal layer is formed on the metal layer lamination surface, which is at least one surface of a resin film, without the use of an adhesive, the method including a step of forming the metal layer on the metal layer lamination surface of the resin film without the use of an adhesive, wherein the root mean square roughness (RMS) and arithmetic mean roughness (Ra) of the metal layer lamination surface of the resin film are both 50 nm or less, and the 180° peel strength between the metal layer and the resin film is 0.6 N / mm or more.

[0014] The root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the metal layer lamination surface of the resin film after removing the metal layer from the metal-clad laminate may both be 50 nm or less, and the haze of the resin film after removing the metal layer from the metal-clad laminate may be 1.0 or less. The method may further include a step of forming an underlayer on the metal layer lamination surface, and the step of forming the metal layer may be a step of forming the metal layer on the underlayer formed on the metal layer lamination surface, or an indium zinc oxide (IZO) thin film may be formed on the metal layer lamination surface as the underlayer. The method may further include a step of forming a bonding layer on the metal layer lamination surface, and the step of forming the metal layer may be a step of bonding the resin film and the metal layer via the bonding layer formed on the metal layer lamination surface. The resin film may be a cycloolefin polymer film, and both surfaces of the resin film may be the metal layer lamination surfaces. In the step of forming the metal layer, the metal layer may be formed on each of the two metal layer lamination surfaces without using the adhesive.

[0015] A pattern having recesses and protrusions may be formed on the metal layer lamination surface of the resin film, and in the process of forming the metal layer, the metal layer may be formed so as to fill the recesses and cover the protrusions of the pattern.

[0016] According to one embodiment of the present disclosure, there is provided a method for manufacturing a wiring board, the method including the step of forming a wiring layer by etching the metal layer of the metal-clad laminate manufactured by the above-described method for manufacturing a metal-clad laminate, wherein the resin film exposed after etching the metal layer has a root mean square (RMS) roughness and an arithmetic mean roughness (Ra) of 50 nm or less, and the resin film exposed after etching the metal layer has a haze of 1.0 or less.

[0017] As one embodiment of the present disclosure, there is provided a method for manufacturing a wiring board, which includes a step of forming a wiring layer by chemically mechanically polishing the metal layer so as to expose the tops of the convex portions of the pattern of the metal-clad laminate manufactured by the above-mentioned method for manufacturing a metal-clad laminate.

[0018] As one embodiment of the present disclosure, there is provided a method for manufacturing a wiring board, including the steps of forming a resist pattern having openings on the metal layer of the metal-clad laminate manufactured by the above-mentioned method for manufacturing a metal-clad laminate, forming a metal wiring layer in the openings of the resist pattern, removing the resist pattern, and etching the metal layer exposed by removing the resist pattern. [Effects of the Invention]

[0019] According to the present disclosure, it is possible to provide a metal-clad laminate and a wiring board having excellent adhesion between a resin film and a metal layer, and methods for manufacturing the same. [Brief explanation of the drawings]

[0020] [Figure 1A] FIG. 1A is a cross-sectional view showing a schematic configuration of a metal-clad laminate according to one embodiment of the present disclosure. [Figure 1B] FIG. 1B is a cross-sectional view showing a schematic configuration of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 2A] FIG. 2A is a cross-sectional view showing a schematic configuration of another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 2B]FIG. 2B is a cross-sectional view showing a schematic configuration of another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 2C] FIG. 2C is a cross-sectional view showing a schematic configuration of another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 3A] FIG. 3A is a cross-sectional view showing a step of a method for manufacturing a metal-clad laminate according to one embodiment of the present disclosure. [Figure 3B] FIG. 3B is a cross-sectional view showing a step in the method for manufacturing a metal-clad laminate according to an embodiment of the present disclosure, which is a step subsequent to FIG. 3A. [Figure 3C] FIG. 3C is a cross-sectional view showing a step in a method for producing another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 3D] FIG. 3D is a cross-sectional view showing a step following FIG. 3C in a method for producing another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 3E] FIG. 3E is a cross-sectional view showing a step following FIG. 3D in a method for producing another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 3F] FIG. 3F is a cross-sectional view showing a step in a method for producing another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 3G] FIG. 3G is a cross-sectional view showing a step following FIG. 3F in a method for manufacturing another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 3H] FIG. 3H is a cross-sectional view showing a step following FIG. 3G in a method for producing another aspect of a metal-clad laminate according to an embodiment of the present disclosure. [Figure 4A] FIG. 4A is a cross-sectional view showing a schematic configuration of a wiring board according to an embodiment of the present disclosure. [Figure 4B] FIG. 4B is a cross-sectional view showing a schematic configuration of another aspect of the wiring board according to the embodiment of the present disclosure. [Figure 4C] FIG. 4C is a cross-sectional view showing a schematic configuration of another aspect of the wiring board according to the embodiment of the present disclosure. [Figure 5A]FIG. 5A is a cross-sectional view showing a step of a method for manufacturing a wiring board according to an embodiment of the present disclosure. [Figure 5B] FIG. 5B is a cross-sectional view showing a step following FIG. 5A in a method for manufacturing a wiring board according to an embodiment of the present disclosure. [Figure 5C] FIG. 5C is a cross-sectional view showing a step in the method for manufacturing a wiring board according to an embodiment of the present disclosure, which step follows FIG. 5B. [Figure 6A] FIG. 6A is a cross-sectional view showing a step of a manufacturing method of another aspect of a wiring board according to an embodiment of the present disclosure. [Figure 6B] FIG. 6B is a cross-sectional view showing a step following FIG. 6A in a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure. [Figure 6C] FIG. 6C is a cross-sectional view showing a step following FIG. 6B in a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure. [Figure 7A] FIG. 7A is a cross-sectional view showing a step of a manufacturing method of another aspect of a wiring board according to an embodiment of the present disclosure. [Figure 7B] FIG. 7B is a cross-sectional view showing a step following FIG. 7A in a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure. [Figure 7C] FIG. 7C is a cross-sectional view showing a step following FIG. 7B in a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure. [Figure 8A] FIG. 8A is a cross-sectional view showing a step of a manufacturing method of another aspect of a wiring board according to an embodiment of the present disclosure. [Figure 8B] FIG. 8B is a cross-sectional view showing a step following FIG. 8A in a manufacturing method of another aspect of the wiring board according to the embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0021] Embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the shape, scale, aspect ratio, etc. of each part may be shown exaggerated or modified from the actual product to facilitate understanding. In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits, respectively. In this specification, terms such as "film," "sheet," and "plate" are not distinguished from one another based on differences in names. For example, "plate" is a concept that includes members that may generally be called "sheet" and "film."

[0022] 1A and 1B are cross-sectional views showing a schematic configuration of a metal-clad laminate according to this embodiment, and FIGS. 2A to 2C are cross-sectional views showing a schematic configuration of another aspect of the metal-clad laminate according to this embodiment.

[0023] The metal-clad laminate 1 according to this embodiment includes a resin film 2 having a first surface 21 and a second surface 22 opposite the first surface 21, and a metal layer 3 laminated on the first surface 21 and the second surface 22 of the resin film 2 as metal layer lamination surfaces without an adhesive. That is, the metal-clad laminate 1 according to this embodiment does not include an adhesive layer between the resin film 2 and the metal layer 3. The metal-clad laminate 1 according to this embodiment has a 180° peel strength of 0.6 N / mm or more, preferably 0.7 N / mm to 3.0 N / mm, and more preferably 1.0 N / mm to 2.5 N / mm. The 180° peel strength may be a value measured in accordance with the 180° peel strength test specified in JIS-K-6854. In this embodiment, the adhesive refers to a resin-based primer that can bond the resin film 2 and the metal layer 3, and examples thereof include an acrylic resin-based primer, a polyester resin-based primer, and an epoxy resin-based primer.

[0024] The resin film 2 may be any flexible substrate commonly used as a wiring substrate, such as a polyester-based resin substrate such as a polyethylene terephthalate (PET) substrate, a polyimide-based resin substrate such as a polyimide substrate, an acrylic-based resin substrate such as a polymethyl methacrylate substrate, a polycarbonate-based resin substrate, a polyolefin-based resin substrate such as a cycloolefin copolymer substrate or a cycloolefin polymer substrate, or a fluororesin substrate such as a perfluoroalkoxyalkane (PFA) substrate. In particular, polyolefin-based resin substrates such as a cycloolefin copolymer substrate or a cycloolefin polymer substrate, or a fluororesin substrate such as a perfluoroalkoxyalkane (PFA) substrate, which have excellent high-frequency characteristics, are preferably used as the resin film 2. Alternatively, the resin film 2 may be a rigid-flexible substrate having a flexible portion made of a flexible material constituting the flexible substrate (e.g., the above-mentioned resin material such as cycloolefin polymer) and a rigid portion made of a rigid material (e.g., glass).

[0025] The planar shape of the resin film 2 when viewed from the first surface 21 side or the second surface 22 side is not particularly limited, and may be, for example, a substantially rectangular shape, a long sheet shape, or the like. Furthermore, the size and thickness of the resin film 2 are not particularly limited. For example, when the metal-clad laminate 1 according to this embodiment is used to manufacture a wiring board, the size of the resin film 2 may be equal to or greater than the size required for the electronic device in which the wiring board is used, and the thickness of the resin film 2 may be set appropriately according to the thickness required for the electronic device in which the wiring board is used. Note that, when the planar shape of the resin film 2 is substantially rectangular, the size of the resin film 2 refers to the length in one direction (e.g., the vertical direction) and the length in a direction perpendicular to the vertical direction (e.g., the horizontal direction).

[0026] The root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the first surface 21 and the second surface 22 of the resin film 2 may both be 50 nm or less, and preferably 0.5 nm to 10 nm. When the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the first surface 21 and the second surface 22 of the resin film 2 are relatively small (e.g., 50 nm or less) and the first surface 21 and the second surface 22 have high flatness, the flatness of the surface of the metal layer 3 facing the first surface 21 and the second surface 22 of the resin film 2 (the surface closest to the resin film 2) is also increased. As a result, it is possible to achieve low transmission loss in a wiring board produced from the metal-clad laminate 1 according to this embodiment and low resistance in the wiring in the wiring board. On the other hand, if the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the first surface 21 and the second surface 22 of the resin film 2 are relatively small (for example, 50 nm or less), the adhesion between the resin film 2 and the metal layer 3 tends to decrease, but in this embodiment, even if the root mean square roughness (Rms) and arithmetic mean roughness (Ra) are both relatively small, the adhesion between the resin film 2 and the metal layer 3 can be improved. The root mean square roughness (Rms) and arithmetic mean roughness (Ra) may be values that can be determined using a non-contact three-dimensional surface profiler (for example, NV6300 MICROSCOPE manufactured by Zygo).

[0027] The haze (Hz) of the resin film 2 may be, for example, 1.0 or less, preferably 0.7 or less, and more preferably 0.1 to 0.5. When the haze (Hz) of the resin film 2 is 1.0 or less, transparency (transparency in the visible light range (wavelengths of 380 nm to 780 nm)) of a wiring board in which wiring is difficult to see is ensured when the metal-clad laminate 1 according to this embodiment is used to manufacture the wiring board. Therefore, the metal-clad laminate 1 according to this embodiment can be particularly suitably used to manufacture wiring boards that require transparency, such as touch panels and planar heaters. The haze (Hz) may be a value determined in accordance with JIS-K-7136 using a haze meter (e.g., HM-150 manufactured by Murakami Color Research Laboratory).

[0028] The metal layer 3 includes a first metal layer 31 laminated on the first surface 21 of the resin film 2 and a second metal layer 32 laminated on the second surface 22. The metal material contained in the metal layer 3 (the first metal layer 31 and the second metal layer 32) may be appropriately selected depending on the intended use of the metal-clad laminate 1 according to the present embodiment, and examples thereof include one or more metals selected from copper, iron, nickel, cobalt, molybdenum, tungsten, titanium, and aluminum. For example, when the metal-clad laminate 1 according to the present embodiment is used for manufacturing a wiring board, the metal layer 3 may be a copper layer or the like having excellent electrical conductivity. The thickness of the metal layer 3 (the first metal layer 31 and the second metal layer 32) may also be appropriately selected depending on the intended use of the metal-clad laminate 1 according to the present embodiment. When the metal-clad laminate 1 according to the present embodiment is used to manufacture a wiring board, the thickness of the metal layer 3 may be appropriately set depending on the characteristic impedance of the wiring board, for example, approximately 1 μm to 50 μm, preferably approximately 12 μm to 35 μm. When the wiring layer 6 (first wiring layer 61 and second wiring layer 62) in the wiring board 10 manufactured using the metal-clad laminate 1 according to the present embodiment includes second layers 612, 622 formed from the metal layer 3 and third layers 613, 623 formed on the second layers 612, 622 (see FIG. 4B), the thickness of the metal layer 3 in the metal-clad laminate 1 may be set depending on the characteristic impedance of the wiring board 10, taking into account the thickness of the third layers 613, 623. Note that the metal layer 3 (first metal layer 31 and second metal layer 32) may have a laminate structure consisting of an electroless metal plating layer or a sputtered metal layer located on the resin film 2 side and an electrolytic metal plating layer located on the electroless metal plating layer or the sputtered metal layer. The electroless metal plating layer or sputtered metal layer functions as a seed layer when the electrolytic metal plating layer is formed by electrolytic plating. In this case, the metal material contained in the electroless metal plating layer or sputtered metal layer and the metal material contained in the electrolytic metal plating layer may be the same metal material or different metal materials.

[0029] In the metal-clad laminate 1 according to this embodiment, an underlayer 4 may be provided between the resin film 2 and the metal layer 3 (see FIG. 1A). By providing the underlayer 4 therebetween, even if the first surface 21 and the second surface 22 of the resin film 2 have high flatness (for example, the root mean square roughness (Rms) and the arithmetic mean roughness (Ra) are both 50 nm or less), the adhesion between the resin film 2 and the metal layer 3 can be improved. Specifically, as shown in FIG. 1A, a first underlayer 41 is provided between the first surface 21 of the resin film 2 and the first metal layer 31, and a second underlayer 42 is provided between the second surface 22 of the resin film 2 and the second metal layer 32.

[0030] Examples of materials constituting the underlayer 4 (first underlayer 41 and second underlayer 42) include metal oxides such as indium zinc oxide (IZO), indium tin oxide (ITO), and zinc oxide (ZnO), and oxide semiconductor materials such as tin oxide (SnO2-based), titanium oxide (TiO2-based), and IGZO. The thickness of the underlayer 4 is not particularly limited, but may be 4 nm or more, and may be approximately 8 nm to 20 nm. If the thickness of the underlayer 4 is less than 4 nm, the first surface 21 and the second surface 22 of the resin film 2 will have portions not covered by the material constituting the underlayer 4 in a sea-island pattern, which may significantly reduce the adhesion strength (180° peel strength) between the metal layer 3 and the resin film 2.

[0031] In the metal-clad laminate 1 according to this embodiment, instead of the base layer 4, bonding layers 5 (first bonding layer 51 and second bonding layer 52) that bond the resin film 2 and the metal layer 3 may be provided (see FIG. 1B ). The bonding layer 5 is formed by chemically bonding a molecular bonding agent to the first surface 21 and the second surface 22, which are the metal layer lamination surfaces of the resin film 2. The metal-clad laminate 1 can be produced by chemically bonding the metal layer 3 to the molecular bonding agent that constitutes the bonding layer 5. Examples of the molecular bonding agent include triazine thiol compounds. The first surface 21 and the second surface 22, which are the metal layer lamination surfaces of the resin film 2, may be pretreated by corona discharge treatment, atmospheric pressure plasma treatment, UV irradiation treatment, or the like, and then a solution containing the molecular bonding agent (e.g., a molecular bonding agent aqueous solution) may be brought into contact with the first surface 21 and the second surface 22 of the pretreated resin film 2 to form the bonding layer 5. The metal layer 3 may then be bonded to the bonding layer 5 by plating or the like.

[0032] As described above, the metal-clad laminate 1 according to this embodiment has a configuration in which the metal layers 3 (first metal layer 31 and second metal layer 32) are laminated on both sides (first side 21 and second side 22) of the resin film 2 via the base layers 4 (first base layer 41 and second base layer 42) or the bonding layers 5 (first bonding layer 51 and second bonding layer 52). This improves the adhesion of the metal layer 3 to the resin film 2, allowing the metal layer 3 to exhibit a 180° peel strength of 0.6 N / mm or more. Furthermore, since the metal layers 3 are laminated on both sides of the resin film 2 without an adhesive, the wiring board 10 (see FIGS. 4A to 4C) manufactured from the metal-clad laminate 1 can exhibit excellent high-frequency characteristics.

[0033] The metal-clad laminate 1 according to the present embodiment is not limited to the above-described embodiment. For example, the metal-clad laminate 1 may have a configuration in which a metal layer 3 (e.g., a first metal layer 31) is laminated on one surface (e.g., a first surface 21) of a resin film 2 via an underlayer 4 (e.g., a first underlayer 41) or a bonding layer 5 (e.g., a first bonding layer 51) (see FIG. 2A). Note that the metal-clad laminate 1 according to the present embodiment may have a configuration in which the metal layer 3 is provided on one surface (e.g., the first surface 21) or both surfaces (the first surface 21 and the second surface 22) of the resin film 2 without the underlayer 4 or the bonding layer 5 interposed therebetween. In this case, a metal foil such as copper foil may be used as the metal layer 3. However, when the metal foil is attached to one or both sides of the resin film 2, the surface roughness (root mean square roughness Rms and arithmetic mean roughness Ra) of the first side 21 and / or the second side 22 of the resin film 2 is affected by the surface roughness of the metal foil in contact with the first side 21 and / or the second side 22. As a result, the surface roughness (root mean square roughness Rms and arithmetic mean roughness Ra) of the first side 21 and / or the second side 22 of the resin film 2 after the metal foil as the metal layer 3 is removed from the metal-clad laminate 1 becomes relatively large (for example, both the root mean square roughness Rms and the arithmetic mean roughness Ra exceed 50 nm). Therefore, in this embodiment, a metal foil having both the root mean square roughness Rms and the arithmetic mean roughness Ra of 50 nm or less may be used.

[0034] 2B, the metal-clad laminate 1 according to the present embodiment may include a pattern 9 (e.g., a resist pattern) having recesses 91 and protrusions 92 (see FIG. 3D) on a first base layer 41 and a second base layer 42 (or a first bonding layer 51 and a second bonding layer 52) provided on the first surface 21 and the second surface 22 of the resin film 2, and a metal layer 3 (a first metal layer 31 and a second metal layer 32) laminated so as to fill the recesses 91 of the pattern 9 and cover the entire pattern 9. In the metal-clad laminate 1 of this embodiment, by removing the metal layer 3 so as to expose the tops of the protrusions 92 of the pattern 9 and patterning the base layers 41, 42 (or the bonding layers 51, 52), a wiring board 10 (see FIG. 4A) can be manufactured in which a wiring layer 6 (a first wiring layer 61 and a second wiring layer 62) composed of the metal layer 3 (a first metal layer 31 and a second metal layer 32) that fills the recesses 91 of the pattern 9 is formed. In the metal-clad laminate 1 of this embodiment (see FIG. 2B), the width W of the recessed portion 91 of the pattern 9 provided on the first surface 21 and the second surface 22 of the resin film 2 is 91 and the pitch P9 of the pattern 9 (see FIG. 3D ), the width W of the wiring layer 6 (the first wiring layer 61 and the second wiring layer 62) in the wiring board 10 manufactured from the metal-clad laminate 1. 61 ,W 62 and pitch P 61 ,P 62 Therefore, the width W of the recess 91 is determined. 91 and pitch P9 is the width W of the wiring layer 6 (first wiring layer 61 and second wiring layer 62) required in the wiring board 10 manufactured from the metal-clad laminate 1. 61 ,W 62 and pitch P 61 ,P 62 It may be set appropriately depending on the situation.

[0035] Furthermore, the metal-clad laminate 1 of this embodiment may comprise, as shown in Figure 2C, a pattern 9 (e.g., a resist pattern) having recesses 91 and protrusions 92 (see Figure 3F) formed on each of the first surface 21 and second surface 22 of the resin film 2, a first base layer 41 and a second base layer 42 (first bonding layer 51 and second bonding layer 52) formed at least on the first surface 21 and second surface 22 of the resin film 2 exposed from the recesses 91 of the pattern 9 (bottom surfaces of the recesses 91 of the pattern 9), and a metal layer 3 (first metal layer 31 and second metal layer 32) laminated so as to fill the recesses 91 of the pattern 9 and cover the entire pattern 9. In the metal-clad laminate 1 of this embodiment, by removing the metal layer 3 so as to expose the tops of the convex portions 92 of the pattern 9, it is possible to manufacture a wiring board 10 (see FIG. 4C ) having formed thereon the wiring layer 6 (first wiring layer 61 and second wiring layer 62) constituted by the metal layer 3 (first metal layer 31 and second metal layer 32) filling the concave portions 91 of the pattern 9. In the metal-clad laminate 1 of this embodiment (see FIG. 2C ), the width W of the concave portions 91 of the pattern 9 provided on the first surface 21 and the second surface 22 of the resin film 2 is 91 and the pitch P9 of the pattern 9 (see FIG. 3F), the width W of the wiring layer 6 (the first wiring layer 61 and the second wiring layer 62) in the wiring board 10 manufactured from the metal-clad laminate 1. 61 ,W 62 and pitch P 61 ,P 62 Therefore, the width W of the recess 91 is determined. 91 and pitch P9 is the width W of the wiring layer 6 (first wiring layer 61 and second wiring layer 62) required in the wiring board 10 manufactured from the metal-clad laminate 1. 61 ,W 62 and pitch P 61 ,P 62 The material for forming the pattern 9 is not particularly limited, and may be, for example, a known resist material, preferably a resist material that is transparent (transmittance of visible light (light with a wavelength of 380 nm to 780 nm) is 90% or more) and has a haze (Hz) of 1.0 or less.

[0036] The metal-clad laminate 1 according to this embodiment can be manufactured, for example, as follows: Figures 3A and 3B are cross-sectional views showing the steps of the method for manufacturing the metal-clad laminate according to this embodiment.

[0037] First, a resin film 2 having a first surface 21 and a second surface 22 located on the opposite side of the first surface 21 is prepared, and an underlayer 4 (first underlayer 41 and second underlayer 42) or a bonding layer 5 (first bonding layer 51 and second bonding layer 52) is formed on each of the first surface 21 and second surface 22 of the resin film 2 (see FIG. 3A ). The underlayer 4 (first underlayer 41 and second underlayer 42) may be formed by, for example, a sputtering method using a metal oxide, which is the constituent material of the underlayer 4, as a target material. The bonding layer 5 (first bonding layer 51 and second bonding layer 52) may be formed by, for example, contacting an aqueous solution containing a molecular bonding agent (e.g., a triazine thiol-based compound) that constitutes the bonding layer 5 with the first surface 21 and second surface 22 of the resin film 2.

[0038] Next, a sputtered metal layer or an electroless plated layer is formed by sputtering or electroless plating using the constituent material of the metal layer 3 as a target substance on the underlayer 4 (first underlayer 41 and second underlayer 42) or the bonding layer 5 (first bonding layer 51 and second bonding layer 52) formed on the first surface 21 and the second surface 22 of the resin film 2. When forming a sputtered metal layer or an electroless plated layer on the bonding layer 5, a catalyzing process may be performed to deposit a Pd catalyst or the like on the bonding layer 5 before the sputtered metal layer or the electroless plated layer is formed. Then, an electrolytic plating layer is formed by electrolytic metal plating using the sputtered metal layer or electroless plating layer and the underlayer 4 (first underlayer 41 and second underlayer 42) or the bonding layer 5 (first bonding layer 51 and second bonding layer 52) as seed layers. This forms a first metal layer 31 consisting of the sputtered metal layer or electroless plating layer and the electrolytic plating layer on the first underlayer 41 or the first bonding layer 51, and a second metal layer 32 consisting of the sputtered metal layer or electroless plating layer and the electrolytic plating layer on the second underlayer 42 or the second bonding layer 52 (see FIG. 3B). In this way, the metal-clad laminate 1 according to this embodiment (see FIGS. 1A and 1B) is manufactured.

[0039] Another aspect of the metal-clad laminate 1 according to this embodiment (see FIG. 2B) can be manufactured, for example, as follows: Figures 3C to 3E are cross-sectional views showing the steps of a manufacturing method for another aspect of the metal-clad laminate according to this embodiment.

[0040] First, a resin film 2 having a first surface 21 and a second surface 22 located on the opposite side of the first surface 21 is prepared, and an underlayer 4 (first underlayer 41 and second underlayer 42) or a bonding layer 5 (first bonding layer 51 and second bonding layer 52) is formed on each of the first surface 21 and second surface 22 of the resin film 2 (see FIG. 3C ). The underlayer 4 (first underlayer 41 and second underlayer 42) may be formed by, for example, a sputtering method using a metal oxide, which is the constituent material of the underlayer 4, as a target material. The bonding layer 5 (first bonding layer 51 and second bonding layer 52) may be formed by, for example, contacting an aqueous solution containing a molecular bonding agent (e.g., a triazine thiol-based compound) that constitutes the bonding layer 5 with the first surface 21 and second surface 22 of the resin film 2.

[0041] Next, a pattern 9 (e.g., a resist pattern) having recesses 91 and protrusions 92 is formed on the base layer 4 or the bonding layer 5 formed on each of the first surface 21 and the second surface 22 of the resin film 2 (see FIG. 3D ). The method for forming the pattern 9 is not particularly limited. For example, when the pattern 9 is a resist pattern, a resist layer may be formed on the base layer 4 or the bonding layer 5 by a conventionally known coating film formation method (die coating or spin coating of a resist material, lamination of a dry film resist, etc.), and the resist layer may be patterned (photolithography, imprint lithography, etc.), or the pattern 9 may be formed by printing a resist material, etc.

[0042] Then, a sputtered metal layer or an electroless plated layer is formed on the resin film 2 having the pattern 9 formed on the first surface 21 and the second surface 22 by sputtering or electroless plating using the constituent material of the metal layer 3 as a target material. Thereafter, a metal plating layer (electrolytic plating layer or electroless plating layer) is formed so as to fill the recesses 91 of the pattern 9 and cover the entire pattern 9, thereby forming a metal layer 3 (first metal layer 31 and second metal layer 32) consisting of the sputtered metal layer and the metal plating layer on the base layer 4 or the bonding layer 5 (see FIG. 3E). In this manner, the metal-clad laminate 1 (see FIG. 2B) according to this embodiment is manufactured. In the embodiment shown in FIG. 3E, the metal plating layer is formed to cover the entire pattern 9, but this is not limiting. For example, the metal plating layer may be formed so as to fill the recesses 91 of the pattern 9 but not cover the entire pattern 9, exposing the tops of the protrusions 92 of the pattern 9. In this case, the film thickness of the metal plating layer may be the same as the height of the convex portions 92 of the pattern 9, or may be smaller than the height of the convex portions 92 of the pattern 9.

[0043] Another aspect of the metal-clad laminate 1 according to this embodiment (see FIG. 2C) can be manufactured, for example, as follows: Figures 3F to 3H are cross-sectional views showing the steps of a manufacturing method for another aspect of the metal-clad laminate according to this embodiment.

[0044] First, a resin film 2 having a first surface 21 and a second surface 22 located opposite the first surface 21 is prepared, and a pattern 9 (e.g., a resist pattern) having recesses 91 and protrusions 92 is formed on each of the first surface 21 and the second surface 22 of the resin film 2 (see FIG. 3F ). The method for forming the pattern 9 is not particularly limited. For example, when the pattern 9 is a resist pattern, a resist layer is formed on the first surface 21 and the second surface 22 by a conventionally known coating film formation method (die coating or spin coating of a resist material, lamination of a dry film resist, etc.), and the pattern 9 may be formed by patterning the resist layer (photolithography, imprint lithography, etc.) or by printing a resist material, etc.

[0045] Next, an underlayer 4 (first underlayer 41 and second underlayer 42) or a bonding layer 5 (first bonding layer 51 and second bonding layer 52) is formed on the first surface 21 and the second surface 22 (bottom surfaces of the recesses 91 of the pattern 9) of the resin film 2 exposed from the recesses 91 of the pattern 9 (see FIG. 3G). The underlayer 4 (first underlayer 41 and second underlayer 42) may be formed by, for example, a sputtering method using a metal oxide, which is the constituent material of the underlayer 4, as a target material. The bonding layer 5 (first bonding layer 51 and second bonding layer 52) may be formed by, for example, contacting the first surface 21 and the second surface 22 of the resin film 2 with an aqueous solution containing a molecular bonding agent (e.g., a triazine thiol-based compound) that constitutes the bonding layer 5. The underlayer 4 or the bonding layer 5 may be formed at least on the bottom surfaces of the recesses 91 of the pattern 9, but may also be formed on the side surfaces and tops of the protrusions 92 of the pattern 9.

[0046] Then, on the resin film 2 having the pattern 9 and the base layer 4 (or the bonding layer 5) formed on the first surface 21 and the second surface 22, a sputtered metal layer or an electroless plated layer is formed by sputtering or electroless plating using the constituent material of the metal layer 3 as a target material. Thereafter, a metal plating layer (electrolytic plating layer or electroless plating layer) is formed so as to fill the recesses 91 of the pattern 9 and cover the entire pattern 9, thereby forming a metal layer 3 (first metal layer 31 and second metal layer 32) consisting of the sputtered metal layer and the metal plating layer on the base layer 4 or the bonding layer 5 (see FIG. 3H ). In this manner, the metal-clad laminate 1 (see FIG. 2C ) according to this embodiment is manufactured. In the embodiment shown in FIG. 3H , the metal plating layer is formed to cover the entire pattern 9, but this is not limiting. For example, the metal plating layer may be formed so as to fill the recesses 91 of the pattern 9 but not to cover the entire pattern 9, exposing the tops of the protrusions 92 of the pattern 9. In this case, the film thickness of the metal plating layer may be the same as the height of the convex portions 92 of the pattern 9, or may be smaller than the height of the convex portions 92 of the pattern 9.

[0047] Next, a wiring board 10 manufactured from the metal-clad laminate 1 according to this embodiment will be described. FIGS. 4A to 4C are cross-sectional views showing a schematic configuration of the wiring board 10 according to this embodiment. In this embodiment, the wiring board 10 manufactured from the metal-clad laminate 1 shown in FIGS. 1A, 2B, and 2C will be described as an example. However, it goes without saying that the wiring board manufactured from the metal-clad laminate 1 shown in FIGS. 1B and 2A or the metal-clad laminate 1 in which the metal layer 3 (metal foil) is provided on the first surface 21 and / or the second surface 22 of the resin film 2 without an underlying layer 4 (or bonding layer 5) also has a configuration similar to that of the wiring board manufactured from the metal-clad laminate 1 shown in FIG. 1A. Furthermore, in the wiring board 10, components similar to those of the metal-clad laminate 1 according to this embodiment will be designated by the same reference numerals, and detailed description thereof will be omitted.

[0048] The wiring board 10 in this embodiment has a resin film 2 having a first surface 21 and a second surface 22 located on the opposite side of the first surface 21, and a wiring layer 6 including a first wiring layer 61 formed on the first surface 21 of the resin film 2 and a second wiring layer 62 formed on the second surface 22. The first wiring layer 61 and the second wiring layer 62 may be formed on the substantially flat first surface 21 and second surface 22, respectively (see FIGS. 4A and 4B), or may be embedded in recesses 91 of patterns 9 formed on the first surface 21 and second surface 22 (see FIG. 4C). The wiring layer 6 (first wiring layer 61 and second wiring layer 62) may have a laminated structure in which first layers 611, 621 based on the base layer 4 (first base layer 41 and second base layer 42) or the bonding layer 5 (first bonding layer 51 and second bonding layer 52) and second layers 612, 622 based on the metal layer 3 (first metal layer 31 and second metal layer 32) are laminated in this order from the resin film 2 side (see FIGS. 4A and 4C ). and second base layer 42) or bonding layer 5 (first bonding layer 51 and second bonding layer 52), second layers 612 and 622 based on metal layer 3 (first metal layer 31 and second metal layer 32), and third layers 613 and 623 based on metal wiring layer 8 (first metal wiring layer 81 and second metal wiring layer 82, see Figure 6A), may have a laminated structure in which these are laminated in this order from the resin film 2 side (see Figure 4B). In the embodiment shown in FIG. 4B, the material constituting the third layer 613, 623 (metal wiring layer 8 (first metal wiring layer 81 and second metal wiring layer 82), see FIG. 6A) may be, for example, one or more selected from copper, iron, nickel, cobalt, molybdenum, tungsten, titanium, and aluminum, and may be the same material as or a different material from the material constituting the first layer 611, 621 (metal layer 3 (first metal layer 31 and second metal layer 32)). The wiring board 10 in this embodiment may be mounted with one or more electronic components depending on the type of electronic device in which the wiring board 10 is used, may be a wiring board for a touch panel, or may be used as a planar heater.

[0049] When the first layers 611, 621 in the wiring layer 6 (first wiring layer 61 and second wiring layer 62) are based on a bonding layer 5 made of an electrically insulating material, the first layers 611, 612 may be continuous on the first surface 21 and the second surface 22 of the resin film 2. That is, the wiring board 10 of this embodiment includes the resin film 2, the bonding layers 5 located on the first surface 21 and the second surface 22 of the resin film 2, and the wiring layer 6 (first wiring layer 61 and second wiring layer 62) made of the second layers 612, 622 located on each bonding layer 5. A pattern 9 (protrusion 92) may or may not be located between the second layers 612, 622 in the wiring layer 6 (first wiring layer 61 and second wiring layer 62). Furthermore, the tops of the second layers 612, 622 of the wiring layer 6 may be located on the same plane as the tops of the convex portions 92 of the pattern 9, or may be located closer to the resin film 2 than the tops of the convex portions 92 of the pattern 9.

[0050] The width W of each wiring in the first wiring layer 61 61 and the width W of each wiring in the second wiring layer 62 62 is not particularly limited, but may be in the range of 0.1 μm to 1000 μm, and preferably in the range of 1 μm to 300 μm. 61 (the distance between adjacent wirings) and the pitch P of each wiring in the second wiring layer 62 62 The distance between adjacent wirings is not particularly limited, but may be, for example, within a range of 0.2 μm to 5000 μm, and preferably within a range of 2 μm to 600 μm. 61 and pitch P 61 , and the width W of each wiring in the second wiring layer 62 62 and pitch P 62 The width W may not be uniform or constant within each of the first surface 21 and the second surface 22 of the resin film 2. For example, one wiring of the first wiring layer 61 has a width W 61 The second wiring layer 62 may have different widths W 62The width W of one wiring of the first wiring layer 61 may be different from the width W of the other wiring. 61 and the width of other wiring W 61 may be different from each other, and the width W of one wiring of the second wiring layer 62 may be different from 62 and the width of other wiring W 62 The width W of the wiring of the first wiring layer 61 may be different from each other. 61 and pitch P 61 and the width W of the wiring of the second wiring layer 62 62 and pitch P 62 may be different from each other.

[0051] 4A and 4B, the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the first surface 21 of the resin film 2 exposed between the wires of the first wiring layer 61 and the second surface 22 of the resin film 2 exposed between the wires of the second wiring layer 62 may both be 50 nm or less, and preferably 0.5 nm to 10 nm. In the wiring board 10 shown in FIG. 4C, the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the first surface 21 and the second surface 22 of the resin film 2 located directly below the pattern 9 may also both be 50 nm or less, and preferably 0.5 nm to 10 nm. When the root mean square roughness (Rms) and arithmetic mean roughness (Ra) are both 50 nm or less, particularly in the embodiment shown in FIG. 4C , pattern 9 is made of a transparent material (e.g., a material with a visible light (wavelength 380 nm to 780 nm) transmittance of 90% or more and a haze (Hz) of 1.0 or less), which ensures transparency of wiring board 10 (transparency in the visible light range (wavelength 380 nm to 780 nm)). As will be described later, wiring board 10 in this embodiment is manufactured by etching or chemical mechanical polishing (CMP) of metal layer 3 of metal-clad laminate 1. The root mean square roughness (Rms) and arithmetic mean roughness (Ra) of first surface 21 and second surface 22 of resin film 2 in metal-clad laminate 1 are both 50 nm or less. That is, it can be said that the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the first surface 21 and the second surface 22 of the resin film 2 are 50 nm or less before etching the metal layer 3 of the metal-clad laminate 1. Since the wiring board 10 in this embodiment is manufactured by etching or performing chemical mechanical polishing (CMP) on the metal layer 3 of the metal-clad laminate 1, it can be said that the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the first surface 21 and the second surface 22 of the resin film 2 exposed after removing the metal layer 3 by etching or chemical mechanical polishing (CMP) in the metal-clad laminate 1 are both 50 nm or less.

[0052] The haze (Hz) of the wiring board 10 in this embodiment may be 1.0 or less, preferably 0.7 or less, and more preferably 0.1 to 0.5. When the haze (Hz) of the wiring board 10 is 1.0 or less, the transparency of the wiring board 10 (transparency in the visible light range (wavelengths of 380 nm to 780 nm)) can be ensured. Therefore, the wiring board 10 in this embodiment is suitable for devices that require transparency, such as touch panels and planar heaters.

[0053] An example of a method for manufacturing the wiring board 10 in this embodiment will be described below. Figures 5A to 5C are cross-sectional views showing the steps of the method for manufacturing the wiring board in this embodiment.

[0054] First, a metal-clad laminate 1 according to this embodiment (see Figures 1A and 1B) is prepared, and a resist layer 70 is formed to cover the metal layer 3 (first metal layer 31 and second metal layer 32) of the metal-clad laminate 1 (see Figure 5A).

[0055] The resist material constituting the resist layer 70 is not particularly limited, and for example, a negative or positive photosensitive material can be used, but it is preferable to use a negative photosensitive material. The wiring layer is formed by etching the metal layer 3 (first metal layer 31 and second metal layer 32) through a mask pattern 71 formed by patterning the resist layer 70. Therefore, the film thickness of the resist layer 70 can be appropriately set depending on the etching selectivity and the like according to the constituent material of the metal layer 3 (first metal layer 31 and second metal layer 32).

[0056] The method for forming the resist layer 70 is not particularly limited, and any conventionally known coating method may be used. For example, a method may be used in which a resist material constituting the resist layer 70 is applied onto the metal layer 3 (the first metal layer 31 and the second metal layer 32) by die coating, spin coating, or the like. Alternatively, a dry film resist made of the resist material may be laminated onto the metal layer 3 (the first metal layer 31 and the second metal layer 32) using a laminator or the like.

[0057] Next, the resist layer 70 is patterned to form a mask pattern 71 corresponding to the first wiring layer 61 and the second wiring layer 62 (see FIG. 5B). The resist layer 70 may be patterned, for example, by photolithography using exposure and development via a photomask corresponding to the mask pattern 71, or by imprint lithography using an imprint mold having a relief structure corresponding to the mask pattern 71. Note that instead of forming the resist layer 70 and patterning it, the mask pattern 71 corresponding to the first wiring layer 61 and the second wiring layer 62 may be formed on the metal layer 3 (the first metal layer 31 and the second metal layer 32) by printing the resist material.

[0058] Then, the metal layer 3 (first metal layer 31 and second metal layer 32) and the base layer 4 (first base layer 41 and second base layer 42) or the bonding layer 5 (first bonding layer 51 and second bonding layer 52) are etched (wet etching or dry etching) through the mask pattern 71 to form a first wiring layer 61 on the first surface 21 of the resin film 2 and a second wiring layer 62 on the second surface 22 (see FIG. 5C). The etching solution used to wet-etch the metal layer 3 and the base layer 4 or the bonding layer 5 may be appropriately selected depending on the constituent materials of the metal layer 3 and the base layer 4 or the bonding layer 5. In this manner, the wiring board 10 (see FIG. 4A) of this embodiment can be manufactured.

[0059] Another example of a method for manufacturing wiring board 10 according to this embodiment will now be described. Figures 6A to 6C are cross-sectional views showing the steps of another aspect of the method for manufacturing wiring board 10 according to this embodiment.

[0060] First, a metal-clad laminate 1 according to the present embodiment (see FIGS. 1A and 1B ) is prepared, and a resist layer 70 is formed to cover the metal layer 3 (first metal layer 31 and second metal layer 32) of the metal-clad laminate 1 (see FIG. 5A ). The resist layer 70 is then patterned to form a resist pattern 71 on the metal layer 3 (first metal layer 31 and second metal layer 32) (see FIG. 5B ). As will be described later, third layers 613 and 623 formed in recesses (openings) of the resist pattern 71 constitute part of the wiring layer 6 (first wiring layer 61 and second wiring layer 62). Therefore, the dimensions (e.g., width in the short-side direction of the recesses (openings)) and planar shape (e.g., line-and-space shape, key shape, etc.) of the recesses (openings) of the resist pattern 71 may be appropriately set in accordance with wiring rules, etc., required for the wiring board 10 to be manufactured.

[0061] Next, the metal wiring layer 8 (first metal wiring layer 81 and second metal wiring layer 82) is formed (see FIG. 6A) so as to fill the recesses (openings) of the resist pattern 71. The metal wiring layer 8 (first metal wiring layer 81 and second metal wiring layer 82) can be formed, for example, by electroless plating using the materials that constitute them.

[0062] Next, the resist pattern 71 is removed to form third layers 613 and 623 constituting part of the wiring layer 6 (first wiring layer 61 and second wiring layer 62) on the metal layer 3 (first metal layer 31 and second metal layer 32) (see FIG. 6B). Then, the metal layer 3 (first metal layer 31 and second metal layer 32) and the base layer 4 (first base layer 41 and second base layer 42) or the bonding layer 5 (first bonding layer 51 and second bonding layer 52) are etched to form the wiring layer 6 (first wiring layer 61 and second wiring layer 62) having a layered structure in which the first layers 611 and 621, the second layers 612 and 622, and the third layers 613 and 623 are layered in this order from the resin film 2 side (see FIG. 6C). In this manner, the wiring board 10 (see FIG. 4B) of this embodiment can be manufactured.

[0063] Another example of a method for manufacturing wiring board 10 according to this embodiment will now be described. Figures 7A to 7C are cross-sectional views illustrating the steps of another aspect of the method for manufacturing wiring board 10 according to this embodiment.

[0064] A metal-clad laminate 1 according to this embodiment (see FIG. 2B) is prepared (see FIG. 7A), and the metal layer 3 (first metal layer 31 and second metal layer 32) of the metal-clad laminate 1 is subjected to chemical mechanical polishing (CMP) to expose the tops of the convex portions 92 of the pattern 9 (see FIG. 7B). This forms second layers 612, 622 embedded in the concave portions 91 of the pattern 9 formed on the first surface 21 and the second surface 22 of the resin film 2.

[0065] Next, the pattern 9 (protrusions 92) is removed, and the underlying layer 4 (or the bonding layer 5) exposed by the removal of the pattern 9 (protrusions 92) is removed by etching (wet etching or dry etching) (see FIG. 7C). As a result, the first layers 611, 621 are formed on the resin film 2 side of the second layers 612, 622, and the wiring layer 6 (first wiring layer 61 and second wiring layer 62) is formed in which the first layers 611, 621 and the second layers 612, 622 are laminated in this order from the resin film 2 side. In this manner, the wiring board 10 (see FIG. 4A) of this embodiment can be manufactured. Note that if the pattern 9 (protrusions 92) in the metal-clad laminate 1 is made of a transparent material, has a haze of 1.0 or less, and the bonding layer 5 is made of an electrically insulating material, the wiring board 10 including the pattern 9 may be manufactured without removing the pattern 9 after exposing the tops of the protrusions 92 of the pattern 9 (see FIG. 7B).

[0066] Another example of the method for manufacturing wiring board 10 according to this embodiment will now be described. Figures 8A and 8B are cross-sectional views showing the steps of another aspect of the method for manufacturing wiring board 10 according to this embodiment.

[0067] A metal-clad laminate 1 according to this embodiment (see FIG. 2C) is prepared (see FIG. 8A), and a chemical mechanical polishing (CMP) process is performed on the metal layer 3 (first metal layer 31 and second metal layer 32) of the metal-clad laminate 1 so as to expose the tops of the convex portions 92 of the pattern 9 (see FIG. 8B). This results in the formation of the wiring layer 6 (first wiring layer 61 and second wiring layer 62) embedded in the concave portions 91 of the pattern 9 formed on the first surface 21 and the second surface 22 of the resin film 2. In this manner, the wiring board 10 according to this embodiment (see FIG. 4C) can be manufactured. The wiring board 10 having the configuration shown in FIG. 4A may be manufactured by removing the pattern 9 from the wiring board 10 manufactured in this manner (see FIG. 4C).

[0068] According to the method for manufacturing wiring board 10 of the present embodiment, since the 180° peel strength between resin film 2 and metal layer 3 in metal-clad laminate 1 is 0.6 N / mm or more, sufficient adhesion required for patterning metal layer 3 can be obtained, and wiring layer 6 (first wiring layer 61 and second wiring layer 62) can be formed with high precision. Furthermore, since the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of first surface 21 and second surface 22 (metal layer lamination surface) of resin film 2 exposed after etching metal layer 3 and base layer 4 or bonding layer 5 are both 50 nm or less, and the haze of resin film 2 after etching metal layer 3 and base layer 4 or bonding layer 5 is 1.0 or less, transparency of wiring board 10 (transparency in the visible light range (wavelengths 380 nm to 780 nm)) can be ensured.

[0069] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Example]

[0070] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0071] [Test Example 1] A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as the resin film 2. Both surfaces of the cycloolefin polymer film were plasma cleaned (plasma treated), and then a 15 nm thick IZO thin film was formed on both surfaces of the cycloolefin polymer film by sputtering. Next, a 200 nm thick copper thin film was formed on the IZO thin film by sputtering. Subsequently, an electrolytic plating process was performed to form a 12 μm thick electrolytic copper plating layer on the copper thin film, thereby producing a metal-clad laminate 1 (Sample 1) having a metal layer 3 consisting of a copper thin film and an electrolytic copper plating layer.

[0072] The 180° peel strength of the metal-clad laminate 1 produced as described above was measured as follows. First, a test specimen was prepared by forming a 10 mm wide cut in the copper layer on one side of the resin film 2 of the metal-clad laminate 1. In accordance with JIS-K-6854, a 180° peel test was performed on the test specimen using a load-displacement measuring unit (FSA-1KE-50N, manufactured by Imada Co., Ltd.), and the 180° peel strength was measured. The results are shown in Table 1.

[0073] The electrolytic copper plating layer, copper thin film, and IZO thin film of the metal-clad laminate 1 prepared as described above were etched using a copper etching solution (Meltex, Melstrip Cu-3931). The total light transmittance and haze (Hz) of the resin film 2 after the electrolytic copper plating layer, copper thin film, and IZO thin film were etched were measured using a haze meter (Murakami Color Research Laboratory, HM-150). The results are shown in Table 1.

[0074] The root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the surface of the resin film 2 after etching the electrolytic copper plating layer, the copper thin film, and the IZO thin film were measured using a non-contact three-dimensional surface profiler (NV6300 MICROSCOPE, manufactured by Zygo Corporation). The results are shown in Table 1.

[0075] [Test Example 2] A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as the resin film 2, and the cycloolefin polymer film was immersed in an aqueous triazine thiol compound solution. Next, a Pd catalyst addition treatment (catalyzing treatment) was performed on the triazine thiol compound thin film formed on both surfaces of the cycloolefin polymer film by immersion in the aqueous triazine thiol compound solution, and then a copper thin film (200 nm thick) was formed on the triazine thiol compound thin film by electroless copper plating. Subsequently, an electrolytic plating treatment was performed to form an electrolytic copper plating layer with a thickness of 12 μm on the copper thin film, thereby producing a metal-clad laminate 1 (Sample 2). The 180° peel strength of the metal-clad laminate 1 thus produced was measured in the same manner as in Test Example 1, and the total light transmittance and haze (Hz) of the resin film 2 after etching the electrolytic copper plating layer, the copper thin film, and the triazine thiol compound thin film of the metal-clad laminate 1, as well as the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the surface of the resin film 2 were measured in the same manner as in Example 1. The results are shown in Table 1.

[0076] [Test Example 3] A metal-clad laminate (Sample 3) was prepared in the same manner as in Test Example 1, except that a 4-nm-thick NiCr alloy thin film was formed by sputtering instead of the IZO thin film. The 180° peel strength of the metal-clad laminate, the total light transmittance and haze (Hz) of the resin film after etching the electrolytic copper plating layer of the metal-clad laminate, the copper thin film, and the NiCr alloy thin film, as well as the root-mean-square roughness (Rms) and arithmetic mean roughness (Ra) of the resin film surface were measured. The results are shown in Table 1.

[0077] [Test Example 4] A metal-clad laminate (Sample 4) was prepared in the same manner as in Test Example 3, except that the thickness of the NiCr alloy thin film was changed to 12 nm. The 180° peel strength of the metal-clad laminate, the total light transmittance and haze (Hz) of the resin film after etching the electrolytic copper plating layer of the metal-clad laminate, the copper thin film, and the NiCr alloy thin film, as well as the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the resin film surface were measured. The results are shown in Table 1.

[0078] [Test Example 5] A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as the resin film. The surface of the resin film was plasma cleaned, and then copper foil (Fukuda Metal Foil & Powder Co., Ltd., ultra-low roughness, non-roughened electrolytic copper foil CF-T9DA-SV) was laminated to the surface of the resin film using a hot press at 220°C to produce a metal-clad laminate (Sample 5). The 180° peel strength of the metal-clad laminate, the total light transmittance and haze (Hz) of the resin film after etching the copper foil, and the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the resin film surface were measured in the same manner as in Test Example 1. The results are shown in Table 1.

[0079] [Test Example 6] A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as the resin film, and a polyester primer was applied to a thickness of 100 nm by wet coating. After the primer layer dried, a 200 nm thick copper vapor deposition film was formed on the primer layer. Subsequently, electrolytic plating was performed to form a 12 μm thick electrolytic copper plating layer on the copper vapor deposition film, thereby producing a metal-clad laminate (Sample 6). The 180° peel strength of the metal-clad laminate, the total light transmittance and haze (Hz) of the resin film after etching the electrolytic copper plating layer and the copper vapor deposition film, and the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the resin film surface were measured in the same manner as in Test Example 1. The results are shown in Table 1.

[0080] [Test Example 7] A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as the resin film. The surface of the resin film was plasma-cleaned, and then a triazine thiol compound was applied to a film thickness of 10 nm and dried. A copper foil (Fukuda Metal Foil and Powder Co., Ltd., ultra-low roughness, non-roughened electrolytic copper foil CF-T9DA-SV) was then laminated to the resin film in a vacuum hot press at 150°C, 4 MPa, and 10 minutes to produce a metal-clad laminate (Sample 7). The 180° peel strength of the metal-clad laminate 1, the total light transmittance and haze (Hz) of the resin film after etching the copper foil, and the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the resin film surface were measured in the same manner as in Test Example 1. The results are shown in Table 1.

[0081] [Table 1]

[0082] As is clear from the results shown in Table 1, the metal-clad laminates 1 (Sample 1, Sample 2) of Test Examples 1 and 2 had a 180° peel strength of 0.6 N / mm or more, indicating excellent adhesion between the resin film 2 and the metal layer 3. On the other hand, Test Examples 3 and 4 (Sample 3, Sample 4), which used a NiCr thin film as the underlayer, showed excellent results in terms of total light transmittance and haze, which are indicators of transparency, and root-mean-square roughness (Rms) and arithmetic mean roughness (Ra), which are indicators of surface roughness, but had insufficient 180° peel strength. Test Example 6 (Sample 6), in which the resin film and metal layer were bonded using a polyester primer, showed excellent 180° peel strength, but a high haze (Hz) of 1.4. Furthermore, the presence of an adhesive layer between the resin film and the metal layer is thought to result in poor high-frequency characteristics. Furthermore, in test example 7 (Sample 7), in which a metal layer was formed on the surface of a resin film without an underlying layer 4 or an adhesive layer 5, although good 180° peel strength was exhibited, the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the resin film after the metal layer was removed were poor.

[0083] Furthermore, when a wiring board is fabricated from a metal-clad laminate using a NiCr thin film as the base layer and a copper layer as the metal layer, as in Test Examples 3 and 4 (Sample 3, Sample 4), the wiring layer formed by etching the copper layer is also etched when the NiCr thin film is etched, which may result in a decrease in the accuracy of the dimensions (e.g., width) and shape (cross-sectional shape) of the wiring layer. Furthermore, the wiring layer contains Ni, a magnetic material, which may result in an increase in transmission loss due to the skin effect. In this regard, by fabricating a wiring board from a metal-clad laminate 1 having an IZO thin film as the base layer 4, a triazine thiol compound thin film as the bonding layer 5, and a copper layer as the metal layer 3, as in Test Examples 1 and 2 (Sample 1, Sample 2), it is possible to suppress a decrease in the accuracy of the dimensions (e.g., width) and shape (cross-sectional shape) of the wiring layer and an increase in transmission loss. [Explanation of symbols]

[0084] 1…Metal clad laminate 2...Resin film 21...Side 1 22…Second side 3...Metal layer 31...first metal layer 32…Second metal layer 4…base layer 41…1st base layer 42…Second base layer 5...Joining layer 51...First bonding layer 52…Second bonding layer 6...Wiring layer 61...1st wiring layer 62…Second wiring layer 9...Pattern 91...recess 92...Convex part 10...Wiring board

Claims

[Claim 1] A metal-clad laminate comprising a resin film and a metal layer laminated on at least one surface of the resin film, that is, a metal layer lamination surface, without an adhesive, A metal-clad laminate in which the 180° peel strength between the metal layer and the resin film is 0.6 N / mm or more.

Images