JP7694076B2 - Metal-clad laminate, wiring board, and manufacturing method thereof - Google Patents

Description

This 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.

In recent years, with the increasing sophistication of electronic devices and the increasing frequency of signals processed by electronic devices, there is a demand for flexible wiring boards and the like that can exhibit excellent high-frequency characteristics, as well as metal-clad laminates and the like that can be used to manufacture such flexible wiring boards. With regard to such flexible wiring boards and the like, flexible wiring boards that use cycloolefin polymer film as a substrate and metal-clad laminates that use cycloolefin polymer film have been proposed from the viewpoint of excellent high-frequency characteristics.

Conventionally, a metal-clad laminate has been known that has 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).

Patent No. 6299226

In the metal-clad laminate described in Patent Document 1, a metal layer (base metal layer and copper layer) is 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 one of the important factors for the reliability of a flexible wiring board manufactured from the metal-clad laminate. On the other hand, if the polymer film and the metal layer are bonded with an adhesive to improve the adhesion between them, the presence of the adhesive layer will deteriorate the high-frequency characteristics. In the metal-clad laminate described in Patent Document 1, a metal layer is formed on the surface of the cycloolefin polymer film without using an adhesive, so that the deterioration of the high-frequency characteristics due to the presence of the adhesive layer can be suppressed. However, there is a problem in that the adhesion between the cycloolefin polymer film and the metal layer is insufficient.

In view of the above problems, an object of the present disclosure is to provide a metal-clad laminate, a wiring board, and a method for manufacturing the same that have excellent adhesion between a resin film and a metal layer.

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, that is, the metal layer lamination surface, in which the 180° peel strength between the metal layer and the resin film is 0.6 N/mm or more.

The root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the metal layer laminated surface exposed after removing the metal layer may both be 50 nm or less, and the haze of the resin film after removing the metal layer may be 1.0 or less. The resin film may further include a base layer formed between the metal layer and the metal layer laminated surface, and the base layer 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.

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.

As one embodiment of the present disclosure, a wiring board is provided that includes a wiring layer formed by etching the metal layer of the metal-clad laminate.

As one embodiment of the present disclosure, a wiring board is provided that includes a wiring layer formed as a portion embedded in the recess by removing the metal layer so as to expose the tops of the protrusions of the pattern of the metal-clad laminate.

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

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 at least one surface, that is, a metal layer lamination 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, 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.

The metal layer lamination surface of the resin film after removing the metal layer from the metal-clad laminate may have a root mean square roughness (Rms) and an arithmetic mean roughness (Ra) of 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 further includes a step of forming a base layer 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 base layer formed on the metal layer lamination surface, and an indium zinc oxide (IZO) thin film may be formed on the metal layer lamination surface as the base layer. The method further includes 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 are the metal layer lamination surfaces, and in the step of forming the metal layer, the metal layer may be formed on each of the two metal layer lamination surfaces without the adhesive.

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.

As one embodiment of the present disclosure, a method for manufacturing a wiring board is provided, which includes a step of forming a wiring layer by etching the metal layer of the metal-clad laminate manufactured by the above-mentioned method for manufacturing a metal-clad laminate. The root mean square roughness (RMS) and arithmetic mean roughness (Ra) of the resin film exposed after etching the metal layer may both be 50 nm or less, and the haze of the resin film exposed after etching the metal layer may be 1.0 or less.

As one embodiment of the present disclosure, a method for manufacturing a wiring board is provided, which includes a step of forming a wiring layer by chemically and 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-described method for manufacturing a metal-clad laminate.

As one embodiment of the present disclosure, a method for manufacturing a wiring board is provided, which includes the steps of forming a resist pattern having an opening 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 opening of the resist pattern, removing the resist pattern, and etching the metal layer exposed by removing the resist pattern.

The present disclosure provides a metal-clad laminate, a wiring board, and a method for manufacturing the same that have excellent adhesion between the resin film and the metal layer.

FIG. 1A is a cross-sectional view showing a schematic configuration of a metal-clad laminate according to one embodiment of the present disclosure. FIG. 1B is a cross-sectional view showing a schematic configuration of a metal-clad laminate according to one embodiment of the present disclosure. 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. 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. 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. FIG. 3A is a cross-sectional view showing a step of a method for manufacturing a metal-clad laminate according to an embodiment of the present disclosure. FIG. 3B is a cross-sectional view showing a step of a method for manufacturing a metal-clad laminate according to an embodiment of the present disclosure, the step following FIG. 3A. FIG. 3C is a cross-sectional view showing a step of a manufacturing method for another aspect of a metal-clad laminate according to an embodiment of the present disclosure. FIG. 3D is a cross-sectional view showing a step following FIG. 3C as a step in a manufacturing method of another aspect of a metal-clad laminate according to an embodiment of the present disclosure. FIG. 3E is a cross-sectional view showing a step of a manufacturing method of another aspect of a metal-clad laminate according to an embodiment of the present disclosure, the step following FIG. 3D. FIG. 3F is a cross-sectional view showing a step of a manufacturing method for another aspect of a metal-clad laminate according to an embodiment of the present disclosure. FIG. 3G is a cross-sectional view showing a step of a manufacturing method of another aspect of a metal-clad laminate according to an embodiment of the present disclosure, the step following FIG. 3F. FIG. 3H is a cross-sectional view showing a step of a manufacturing method of another aspect of a metal-clad laminate according to an embodiment of the present disclosure, the step following FIG. 3G. FIG. 4A is a cross-sectional view showing a schematic configuration of a wiring board according to an embodiment of the present disclosure. 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. 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. FIG. 5A is a cross-sectional view illustrating a step of a method for manufacturing a wiring board according to an embodiment of the present disclosure. FIG. 5B is a cross-sectional view showing a step of the method for manufacturing a wiring board according to an embodiment of the present disclosure, the step following FIG. 5A. FIG. 5C is a cross-sectional view showing a step of the method for manufacturing a wiring board according to an embodiment of the present disclosure, which is a step subsequent to FIG. 5B. FIG. 6A is a cross-sectional view illustrating a step of a manufacturing method for another aspect of a wiring board according to an embodiment of the present disclosure. FIG. 6B is a cross-sectional view showing a step of a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure, the step following FIG. 6A. FIG. 6C is a cross-sectional view showing a step of a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure, the step following FIG. 6B. FIG. 7A is a cross-sectional view illustrating a step of a manufacturing method of another aspect of a wiring board according to an embodiment of the present disclosure. FIG. 7B is a cross-sectional view showing a step of a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure, the step following FIG. 7A. FIG. 7C is a cross-sectional view showing a step of a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure, the step following FIG. 7B. FIG. 8A is a cross-sectional view illustrating a step of a manufacturing method for another aspect of a wiring board according to an embodiment of the present disclosure. FIG. 8B is a cross-sectional view showing a step of a method for manufacturing another aspect of a wiring board according to an embodiment of the present disclosure, the step following FIG. 8A.

An embodiment 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 modified or exaggerated from the actual product in order to facilitate understanding. In this specification, etc., a numerical range expressed using "~" means that the range includes the numerical values written before and after "~" as the lower and upper limits, respectively. In this specification, etc., terms such as "film,""sheet," and "plate" are not distinguished from each other based on differences in names. For example, "plate" is a concept that includes members that can be generally called "sheet" and "film."

Figures 1A and 1B are cross-sectional views showing the schematic configuration of a metal-clad laminate according to this embodiment, and Figures 2A to 2C are cross-sectional views showing the schematic configuration of other aspects of the metal-clad laminate according to this embodiment.

The metal-clad laminate 1 according to this embodiment includes 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 metal layer 3 laminated on the first surface 21 and the second surface 22 of the resin film 2 as the metal layer lamination surface 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 capable of bonding the resin film 2 and the metal layer 3, and examples of such primer include an acrylic resin-based primer, a polyester resin-based primer, and an epoxy resin-based primer.

The resin film 2 may be any 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, it is preferable to use 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, which has excellent high-frequency characteristics, as the resin film 2. The resin film 2 may also be a rigid-flexible substrate having a flexible portion made of a flexible material (such as the above-mentioned resin material such as cycloolefin polymer) constituting the flexible substrate, and a rigid portion made of a rigid material (such as glass).

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. The size and thickness of the resin film 2 are also 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 larger 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 appropriately set according to the thickness required for the electronic device in which the wiring board is used. Note that the size of the resin film 2 means the length in one direction (e.g., the vertical direction) and the direction perpendicular thereto (e.g., the horizontal direction) when the planar shape of the resin film 2 is substantially rectangular.

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 be 50 nm or less, and are preferably 0.5 nm to 10 nm. 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), and the first surface 21 and the second surface 22 have high flatness, so that 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 high. As a result, it is possible to reduce the transmission loss of the wiring board manufactured from the metal-clad laminate 1 according to this embodiment and to reduce the resistance of 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. However, in this embodiment, even if the root mean square roughness (Rms) and the 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 the arithmetic mean roughness (Ra) may be values that are obtained using a non-contact three-dimensional surface shape measuring device (for example, NV6300 MICROSCOPE manufactured by Zygo Corporation).

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, when a wiring board in which wiring is difficult to see is manufactured from the metal-clad laminate 1 according to this embodiment, the transparency of the wiring board (transparency in the visible light range (wavelength 380 nm to 780 nm)) can be ensured. Therefore, the metal-clad laminate 1 according to this embodiment can be particularly suitably used for manufacturing wiring boards that require transparency, such as touch panels and planar heaters. The haze (Hz) may be a value obtained in accordance with JIS-K-7136 using a haze meter (for example, HM-150 manufactured by Murakami Color Research Laboratory, etc.).

The metal layer 3 has 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 set according to the use of the metal-clad laminate 1 according to this embodiment, and may be one or more selected from copper, iron, nickel, cobalt, molybdenum, tungsten, titanium, and aluminum. For example, when the metal-clad laminate 1 according to this embodiment is used for manufacturing a wiring board, the metal layer 3 may be a copper layer having excellent conductivity. In addition, the thickness of the metal layer 3 (the first metal layer 31 and the second metal layer 32) may be appropriately set according to the use of the metal-clad laminate 1 according to this embodiment. When the metal-clad laminate 1 according to the present embodiment is used for manufacturing a wiring board, the thickness of the metal layer 3 may be appropriately set according to the characteristic impedance of the wiring board, for example, about 1 μm to 50 μm, and preferably about 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 the second layer 612, 622 formed from the metal layer 3 and the third layer 613, 623 formed on the second layer 612, 622 (see FIG. 4B), the thickness of the metal layer 3 in the metal-clad laminate 1 may be set according to the characteristic impedance of the wiring board 10, taking into account the thickness of the third layer 613, 623. The metal layer 3 (first metal layer 31 and second metal layer 32) may have a laminate structure 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 the sputtered metal layer functions as a seed layer when forming the electrolytic metal plating layer by electrolytic plating. In this case, the metal material contained in the electroless metal plating layer or the sputtered metal layer and the metal material contained in the electrolytic metal plating layer may be the same metal material or different metal materials.

In the metal-clad laminate 1 according to this embodiment, a base layer 4 may be provided between the resin film 2 and the metal layer 3 (see FIG. 1A). By providing the base layer 4 between them, 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 base layer 41 is provided between the first surface 21 of the resin film 2 and the first metal layer 31, and a second base layer 42 is provided between the second surface 22 of the resin film 2 and the second metal layer 32.

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 about 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 may have portions that are not covered by the material constituting the underlayer 4 in a sea-island shape, and the adhesion strength (180° peel strength) between the metal layer 3 and the resin film 2 may be extremely reduced.

In the metal-clad laminate 1 according to this embodiment, instead of the base layer 4, a bonding layer 5 (first bonding layer 51 and second bonding layer 52) for bonding 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 constituting this bonding layer 5. Examples of the molecular bonding agent include triazine thiol compounds. Note that the first surface 21 and the second surface 22, which are the metal layer lamination surfaces of the resin film 2, are pretreated with corona discharge treatment, atmospheric pressure plasma treatment, UV irradiation treatment, etc., and then a solution containing a molecular bonding agent (e.g., a molecular bonding agent aqueous solution, etc.) is 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, and the metal layer 3 is bonded to the bonding layer 5 by plating or the like.

As described above, the metal-clad laminate 1 according to this embodiment has a configuration in which the metal layer 3 (first metal layer 31 and second metal layer 32) is laminated on both sides (first side 21 and second side 22) of the resin film 2 via the underlayer 4 (first underlayer 41 and second underlayer 42) or the bonding layer 5 (first bonding layer 51 and second bonding layer 52), thereby improving the adhesion of the metal layer 3 to the resin film 2 and exhibiting a 180° peel strength of 0.6 N/mm or more. In addition, since the metal layer 3 is laminated on both sides of the resin film 2 without the use of an adhesive, the wiring board 10 (see Figures 4A to 4C) manufactured from the metal-clad laminate 1 can exhibit excellent high-frequency characteristics.

The metal-clad laminate 1 according to the present embodiment is not limited to the above-mentioned 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 side (e.g., a first surface 21) of the resin film 2 via a base layer 4 (e.g., a first base layer 41) or a bonding layer 5 (e.g., a first bonding layer 51) (see FIG. 2A). The metal-clad laminate 1 according to the present embodiment may have a configuration in which a metal layer 3 is provided on one side (e.g., a first surface 21) or both sides (the first surface 21 and the second surface 22) of the resin film 2 without any of the base layer 4 and the bonding layer 5. In this case, a metal foil such as a copper foil may be used as the metal layer 3, but 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 surface 21 and/or the second surface 22 of the resin film 2 is affected by the surface roughness of the metal foil in contact with the first surface 21 and/or the second surface 22, and the surface roughness (root mean square roughness Rms and arithmetic mean roughness Ra) of the first surface 21 and/or the second surface 22 of the resin film 2 after removing the metal foil as the metal layer 3 from the metal-clad laminate 1 becomes relatively large (for example, both the root mean square roughness Rms and the arithmetic mean roughness Ra are greater than 50 nm). Therefore, in this embodiment, the metal foil may be one having a root mean square roughness Rms and an arithmetic mean roughness Ra of 50 nm or less.

In addition, the metal-clad laminate 1 according to this embodiment may include a pattern 9 (e.g., a resist pattern) having a recess 91 and a protrusion 92 (see FIG. 3D) on the first base layer 41 and the second base layer 42 (or the first bonding layer 51 and the second bonding layer 52) provided on the first surface 21 and the second surface 22 of the resin film 2, as shown in FIG. 2B, and a metal layer 3 (first metal layer 31 and second metal layer 32) laminated so as to fill the recess 91 of the pattern 9 and cover the entire pattern 9. With this type of metal-clad laminate 1, the metal layer 3 is removed so as to expose the top of the protrusion 92 of the pattern 9, and the base layers 41, 42 (or the bonding layers 51, 52) are patterned, thereby manufacturing a wiring board 10 (see FIG. 4A) in which a wiring layer 6 (first wiring layer 61 and second wiring layer 62) composed of the metal layer 3 (first metal layer 31 and second metal layer 32) that fills the recess 91 of the pattern 9 is formed. In the metal-clad laminate 1 of this embodiment (see FIG. 2B), the width W61, _W62 and pitch P61, _P62 of the wiring layer 6 (first wiring layer 61 and second wiring layer 62) in the wiring board 10 manufactured from the metal-clad laminate 1 are determined by the width W91 of the recess 91 of the pattern 9 provided on the first surface ₂₁ and the second surface 22 of the resin film ₂ and the pitch _P9 of the pattern ₉ (see FIG. 3D). Therefore, the width _W91 and pitch _P9 of the recess 91 may be appropriately set according to the width _W61 , _W62 and pitch _P61 , _P62 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.

Furthermore, as shown in FIG. 2C, the metal-clad laminate 1 of this embodiment may include a pattern 9 (e.g., a resist pattern) having recesses 91 and protrusions 92 (see FIG. 3F) formed on each of the first surface 21 and the second surface 22 of the resin film 2, a first base layer 41 and a second base layer 42 (a first bonding layer 51 and a second bonding layer 52) formed at least on the first surface 21 and the second surface 22 of the resin film 2 (the bottom surface of the recess 91 of the pattern 9) exposed from the recess 91 of the pattern 9, and a metal layer 3 (a first metal layer 31 and a second metal layer 32) laminated so as to fill the recess 91 of the pattern 9 and cover the entire pattern 9. In the case of 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, a wiring board 10 (see FIG. 4C) can be manufactured in which a wiring layer 6 (first wiring layer 61 and second wiring layer 62) composed of the metal layer 3 (first metal layer 31 and second metal layer 32) filling the concave portions 91 of the pattern 9 is formed. In the metal-clad laminate 1 of this embodiment (see FIG. 2C), the widths W ₆₁ and W 62 and pitches P 61 and P 62 of the wiring layer 6 (first wiring layer 61 and second wiring layer 62) in the wiring board 10 manufactured from the metal-clad laminate 1 are determined by the width W ₉₁ 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 and the pitch P ₉ of the pattern ₉ (see FIG. 3F ₎ . Therefore, the width _W91 and pitch _P9 of the recess 91 may be appropriately set according to the widths _W61 , _W62 and pitches _P61 , _P62 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. The material constituting the pattern 9 is not particularly limited and may be, for example, a known resist material, preferably a resist material having transparency (transmittance of visible light (light with a wavelength of 380 nm to 780 nm) of 90% or more) and a haze (Hz) of 1.0 or less.

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 each step of the manufacturing method for the metal-clad laminate according to this embodiment.

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 a base layer 4 (first base layer 41 and second base layer 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 method for forming the base layer 4 (first base layer 41 and second base layer 42) may be, for example, a sputtering method using a metal oxide, which is a constituent material of the base layer 4, as a target material. The method for forming the bonding layer 5 (first bonding layer 51 and second bonding layer 52) may be, for example, a method for contacting an aqueous solution containing a molecular bonding agent (e.g., a triazine thiol compound) constituting the bonding layer 5 with the first surface 21 and the second surface 22 of the resin film 2.

Next, a sputtered metal layer or an electroless plating layer is formed 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 by a sputtering method or an electroless plating process using the constituent material of the metal layer 3 as a target material. When forming a sputtered metal layer or an electroless plating layer on the bonding layer 5, a catalyzing process for precipitating a Pd catalyst or the like on the bonding layer 5 may be performed before forming the sputtered metal layer or the electroless plating layer. Then, 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) are used as seed layers to form an electrolytic plating layer by electrolytic metal plating, forming a first metal layer 31 consisting of a sputtered metal layer or electroless plating layer and an electrolytic plating layer on the first underlayer 41 or the first bonding layer 51, and forming a second metal layer 32 consisting of a sputtered metal layer or electroless plating layer and an 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.

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

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 a base layer 4 (first base layer 41 and second base layer 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 method for forming the base layer 4 (first base layer 41 and second base layer 42) may be, for example, a sputtering method using a metal oxide, which is a constituent material of the base layer 4, as a target material. The method for forming the bonding layer 5 (first bonding layer 51 and second bonding layer 52) may be, for example, a method for contacting an aqueous solution containing a molecular bonding agent (e.g., a triazine thiol compound) constituting the bonding layer 5 with the first surface 21 and the second surface 22 of the resin film 2.

Next, a pattern 9 (e.g., a resist pattern) having recesses 91 and protrusions 92 is formed on the undercoat layer 4 or the bonding layer 5 formed on the first surface 21 and the second surface 22 of the resin film 2 (see FIG. 3D). The method of 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 undercoat layer 4 or the bonding layer 5 by a conventionally known coating formation method (die coating or spin coating of a resist material, lamination of a dry film resist, etc.), and the resist layer is patterned (photolithography, imprint lithography, etc.) or the pattern 9 is formed by printing a resist material, etc.

Then, on the resin film 2 on which the pattern 9 is formed on the first surface 21 and the second surface 22, a sputtered metal layer or an electroless plating layer is formed by a sputtering method or an electroless plating process using the constituent material of the metal layer 3 as a target material. After that, 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 a sputtered metal layer and a metal plating layer on the underlayer 4 or the bonding layer 5 (see FIG. 3E). In this way, 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 so as to cover the entire pattern 9, but this is not limited to this embodiment. 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, and to expose the tops of the protrusions 92 of the pattern 9. In this case, the thickness of the metal plating layer may be the same as the height of the protrusions 92 of the pattern 9, or may be smaller than the height of the protrusions 92 of the pattern 9.

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

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 a pattern 9 (e.g., a resist pattern) having a recess 91 and a protrusion 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 of 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 formation method (die coating, spin coating, etc. of a resist material, lamination of a dry film resist, etc.), and the pattern 9 may be formed by patterning the resist layer (photolithography method, imprint lithography method, etc.) or by printing a resist material, etc.

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

Then, on the resin film 2 on which the pattern 9 and the underlayer 4 (or the bonding layer 5) are formed on the first surface 21 and the second surface 22, a sputtered metal layer or an electroless plating layer is formed by a sputtering method or an electroless plating process using the constituent material of the metal layer 3 as a target material. After that, 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 a sputtered metal layer and a metal plating layer on the underlayer 4 or the bonding layer 5 (see FIG. 3H). In this way, 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 so as to cover the entire pattern 9, but this is not limited to this embodiment. 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, and to expose the tops of the protrusions 92 of the pattern 9. In this case, the thickness of the metal plating layer may be the same as the height of the protrusions 92 of the pattern 9, or may be smaller than the height of the protrusions 92 of the pattern 9.

Next, the 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 and 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 the base layer 4 (or bonding layer 5) has the same configuration as the wiring board manufactured from the metal-clad laminate 1 shown in FIG. 1A. In addition, in the wiring board 10, the same components as those in the metal-clad laminate 1 according to this embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

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 Figures 4A and 4B), or may be embedded in recesses 91 of patterns 9 formed on the first surface 21 and second surface 22 (see Figure 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 underlayer 4 (first underlayer 41 and second underlayer 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 the 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 FIG. 6A) may have a laminated structure in which they are laminated in this order from the resin film 2 side (see FIG. 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 the material constituting the first layer 611, 621 (metal layer 3 (first metal layer 31 and second metal layer 32)), or may be a different material. The wiring board 10 in this embodiment may be mounted with one or more electronic components according to 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 surface heater.

In addition, when the first layers 611, 621 in the wiring layer 6 (first wiring layer 61 and second wiring layer 62) are based on the 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 layer 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) consisting of the second layers 612, 622 located on each bonding layer 5. Between the second layers 612, 622 in this wiring layer 6 (first wiring layer 61 and second wiring layer 62), the pattern 9 (protrusion 92) may be located, or the pattern 9 (protrusion 92) may not be located. In addition, 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.

The width W ₆₁ of each wire in the first wiring layer 61 and the width W ₆₂ of each wire in the second wiring layer 62 are not particularly limited, but may be within a range of, for example, 0.1 μm to 1000 μm, and preferably within a range of 1 μm to 300 μm. The pitch P ₆₁ (the distance between adjacent wires) of each wire in the first wiring layer 61 and the pitch P ₆₂ (the distance between adjacent wires) of each wire in the second wiring layer 62 are not particularly limited, but may be within a range of, for example, 0.2 μm to 5000 μm, and preferably within a range of 2 μm to 600 μm. The width W ₆₁ and pitch P ₆₁ of each wire in the first wiring layer 61 and the width W ₆₂ and pitch P ₆₂ of each wire in the second wiring layer 62 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 wire in the first wiring layer 61 may include a portion having a different width _W61 , and one wire in the second wiring layer 62 may include a portion having a different width _W62 . Furthermore, the width _W61 of one wire in the first wiring layer 61 and the width _W61 of the other wires may be different from each other, and the width W62 of one wire in the second wiring layer ₆₂ and the width W62 of the other wires may be different from each other. Furthermore, the width _W61 and pitch _P61 of the wire in the first wiring layer 61 and the width _W62 and pitch _P62 of the wire in the second wiring layer ₆₂ may be different from each other.

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 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 of the resin film 2 located directly below the pattern 9 may be 50 nm or less, and preferably 0.5 nm to 10 nm. The root mean square roughness (Rms) and arithmetic mean roughness (Ra) are both 50 nm or less, and particularly in the embodiment shown in FIG. 4C, the pattern 9 is made of a transparent material (for example, a material having a visible light (light with a wavelength of 380 nm to 780 nm) transmittance of 90% or more and a haze (Hz) of 1.0 or less), so that the transparency of the wiring board 10 (transparency in the visible light range (wavelength 380 nm to 780 nm)) can be ensured. As will be described later, the wiring board 10 in this embodiment is manufactured through an etching process or a chemical mechanical polishing process (Chemical Mechanical Polishing, CMP) of the metal layer 3 of the metal-clad laminate 1. 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 in the 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 before etching the metal layer 3 of the metal-clad laminate 1 are 50 nm or less. Since the wiring board 10 in this embodiment is manufactured by etching the metal layer 3 of the metal-clad laminate 1 or performing chemical mechanical polishing (CMP), 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.

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. By ensuring that 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 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.

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

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).

The resist material constituting the resist layer 70 is not particularly limited, and may be, for example, a negative or positive photosensitive material, but it is preferable to use a negative photosensitive material. The wiring layer is formed by etching the metal layer 3 (the first metal layer 31 and the 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 according to the etching selectivity ratio according to the constituent material of the metal layer 3 (the first metal layer 31 and the second metal layer 32).

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 the 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 a die coating method, a spin coating method, or the like. Alternatively, a method may be used in which a dry film resist made of the resist material is laminated onto the metal layer 3 (the first metal layer 31 and the second metal layer 32) using a laminator, or the like.

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 a photolithography method using exposure and development through a photomask corresponding to the mask pattern 71, or an imprint lithography method using an imprint mold having a concave-convex 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.

Then, the metal layer 3 (first metal layer 31 and second metal layer 32) 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) 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 for wet etching the metal layer 3 and the underlayer 4 or the bonding layer 5 may be appropriately selected depending on the constituent materials of the metal layer 3 and the underlayer 4 or the bonding layer 5. In this way, the wiring board 10 (see FIG. 4A) in this embodiment can be manufactured.

Another example of the method for manufacturing the wiring board 10 in this embodiment will be described. Figures 6A to 6C are cross-sectional end views showing the steps of another aspect of the method for manufacturing the wiring board 10 in this embodiment.

First, a metal-clad laminate 1 according to this 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). Then, a resist pattern 71 is formed on the metal layer 3 (first metal layer 31 and second metal layer 32) by patterning the resist layer 70 (see FIG. 5B). As described later, the third layers 613 and 623 formed in the 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., the width of the recesses (openings) in the short direction, etc.) and the planar shape (e.g., line-and-space shape, key shape, etc.) of the recesses (openings) of the resist pattern 71 may be appropriately set according to the wiring rules, etc. required for the wiring board 10 to be manufactured.

Next, the metal wiring layer 8 (first metal wiring layer 81 and second metal wiring layer 82) is formed so as to fill the recesses (openings) of the resist pattern 71 (see FIG. 6A). 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 make up the metal wiring layer 8.

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

Another example of the method for manufacturing the wiring board 10 in this embodiment will be described. Figures 7A to 7C are cross-sectional end views showing the steps of another aspect of the method for manufacturing the wiring board 10 in this embodiment.

The metal-clad laminate 1 (see FIG. 2B) according to this embodiment 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 protruding portions 92 of the pattern 9 (see FIG. 7B). This forms second layers 612, 622 embedded in the recesses 91 of the pattern 9 formed on the first surface 21 and second surface 22 of the resin film 2.

Next, the pattern 9 (protrusions 92) is removed, and the base layer 4 (or the bonding layer 5) exposed by removing 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) in which the first layers 611, 621 and the second layers 612, 622 are laminated in order from the resin film 2 side is formed. In this manner, the wiring board 10 (see FIG. 4A) in this embodiment can be manufactured. Note that, when 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 a material having electrical insulation, after exposing the tops of the protrusions 92 of the pattern 9 (see FIG. 7B), the wiring board 10 including the pattern 9 may be manufactured without removing the pattern 9.

Another example of the method for manufacturing the wiring board 10 in this embodiment will be described. Figures 8A and 8B are cross-sectional end views showing the steps of another aspect of the method for manufacturing the wiring board 10 in this embodiment.

The metal-clad laminate 1 (see FIG. 2C) according to this embodiment is prepared (see FIG. 8A), 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) so as to expose the tops of the convex portions 92 of the pattern 9 (see FIG. 8B). This forms 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 (see FIG. 4C) according to this embodiment 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 (see FIG. 4C) manufactured in this manner.

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

The above-described embodiments are described to facilitate understanding of the present invention, and are not described 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.

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.

[Test Example 1]
A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as the resin film 2, and both sides of the cycloolefin polymer film were plasma cleaned (plasma treated), and then a 15 nm-thick IZO thin film was formed by sputtering on both surfaces of the cycloolefin polymer film. Next, a 200 nm-thick copper thin film was formed by sputtering on the IZO thin film. 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.

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, and a 180° peel test was performed on the test specimen using a load-displacement measuring unit (FSA-1KE-50N, manufactured by Imada Co., Ltd.) in accordance with JIS-K-6854 to measure the 180° peel strength. The results are shown in Table 1.

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.

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

[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 solution of a triazine thiol compound. 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 solution of a triazine thiol compound, and then a copper thin film (thickness 200 nm) was formed on the triazine thiol compound thin film by electroless copper plating. Then, 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.

[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, and 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, and the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the surface of the resin film were measured. The results are shown in Table 1.

[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, and 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, and the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the surface of the resin film were measured. The results are shown in Table 1.

[Test Example 5]
A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as a resin film, and the surface of the resin film was plasma cleaned. Then, a copper foil (Fukuda Metal Foil and Powder Co., Ltd., ultra-low roughness non-roughened electrolytic copper foil CF-T9DA-SV) was laminated to the surface of the resin film by 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 surface of the resin film were measured in the same manner as in Test Example 1. The results are shown in Table 1.

[Test Example 6]
A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as a resin film, and a polyester primer was applied to a thickness of 100 nm by wet coating. After drying of the primer layer, a copper vapor deposition film with a thickness of 200 nm was formed on the primer layer. Subsequently, electrolytic plating was performed to form an electrolytic copper plating layer with a thickness of 12 μm 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 surface of the resin film were measured in the same manner as in Test Example 1. The results are shown in Table 1.

[Test Example 7]
A cycloolefin polymer film (ZEON Corporation, Zeonorfilm ZF16-100) was prepared as a resin film, and the surface of the resin film was plasma cleaned, after which a triazine thiol compound was coated with a film thickness of 10 nm and dried. Then, a copper foil (Fukuda Metal Foil and Powder Co., Ltd., ultra-low roughness non-roughened electrolytic copper foil CF-T9DA-SV) was laminated to the resin film at a temperature of 150 ° C., a pressure of 4 MPa, and a time of 10 minutes in a vacuum hot press 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 surface of the resin film were measured in the same manner as in Test Example 1. The results are shown in Table 1.

As is clear from the results shown in Table 1, in the metal-clad laminate 1 of Test Example 1 and Test Example 2 (Sample 1, Sample 2), the 180° peel strength was 0.6 N/mm or more, and the adhesion between the resin film 2 and the metal layer 3 was excellent. On the other hand, in Test Example 3 and Test Example 4 (Sample 3, Sample 4), in which a NiCr thin film was used as the underlayer, the total light transmittance and haze, which are indicators of transparency, and the root mean square roughness Rms and arithmetic mean roughness Ra, which are indicators of surface roughness, were excellent, but the 180° peel strength was insufficient. In Test Example 6 (Sample 6), in which the resin film and the metal layer were bonded using a polyester-based primer, the haze (Hz) was high at 1.4, and it is considered that the high-frequency characteristics are inferior due to the adhesive layer composed of an adhesive being provided between the resin film and the metal layer. Furthermore , in Test Example 7 (Sample 7), in which a metal layer was formed on the surface of a resin film, good 180° peel strength was exhibited, but the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the resin film after the metal layer was removed were poor.

In addition, when a wiring board is fabricated from a metal-clad laminate using a NiCr thin film as the underlayer 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, and there is a risk of the precision of the dimensions (e.g., width) and shape (cross-sectional shape) of the wiring layer decreasing. Furthermore, the wiring layer contains Ni, which is a magnetic material, and as a result, there is a risk of 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 underlayer 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 the decrease in the precision of the dimensions (e.g., width) and shape (cross-sectional shape) of the wiring layer and the increase in transmission loss.

REFERENCE SIGNS LIST 1... Metal-clad laminate 2... Resin film 21... First surface 22... Second surface 3... Metal layer 31... First metal layer 32... Second metal layer 4... Underlayer 41... First underlayer 42... Second underlayer 5... Bonding layer 51... First bonding layer 52... Second bonding layer 6... Wiring layer 61... First wiring layer 62... Second wiring layer 9... Pattern 91... Concave portion 92... Convex portion 10... Wiring board

Claims (15)

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 the use of an adhesive,
The adhesive is composed of a resin-based primer,
a base layer formed between the metal layer and the metal layer stacking surface and made of an indium zinc oxide (IZO) thin film or a bonding layer formed of a triazine thiol compound;
The 180° peel strength between the metal layer and the resin film is 1.0 N/mm or more ;
The metal-clad laminate , wherein the resin film is a cycloolefin polymer film or a cycloolefin copolymer substrate . The metal-clad laminate according to claim 1, wherein the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the metal layer laminate surface exposed after removing the metal layer are both 50 nm or less. Both surfaces of the resin film are the metal layer lamination surfaces,
The metal-clad laminate according to claim 1 or 2 , wherein the metal layer is laminated on the base layer or the bonding layer located on each of the two metal layer lamination surfaces. a pattern having recesses and protrusions is formed on the metal layer lamination surface of the resin film,
4. The metal-clad laminate according to claim 1 , wherein the metal layer is laminated so as to fill the recess and cover the metal layer lamination surface. A wiring board comprising a resin film and a wiring layer provided on at least one surface of the resin film, which is a metal layer laminated surface, without using an adhesive,
The adhesive is composed of a resin-based primer,
the wiring layer includes a first layer located on the metal layer stacking surface and a second layer located on the first layer,
the first layer is composed of an indium zinc oxide (IZO) thin film or a triazine thiol compound;
the second layer is composed of an electroless metal plating layer or a sputtered metal layer located on the first layer, and an electrolytic metal plating layer located on the electroless metal plating layer or the sputtered metal layer,
The 180° peel strength between the wiring layer and the resin film is 1.0 N/mm or more,
The wiring board , wherein the resin film is a cycloolefin polymer film or a cycloolefin copolymer substrate . 6. The wiring board according to claim 5, wherein the wiring layer includes a third layer made of an electroless metal plating layer located on the electrolytic metal plating layer of the second layer . A method for producing a metal-clad laminate in which a metal layer is formed on at least one surface of a resin film, that is, a metal layer lamination surface, without the use of an adhesive, comprising the steps of:
The adhesive is composed of a resin-based primer,
forming an underlayer made of an indium zinc oxide (IZO) thin film or a bonding layer made of a triazine thiol compound on the metal layer laminated surface of the resin film;
forming the metal layer on the underlayer or the bonding layer ;
The step of forming the metal layer includes a step of forming an electroless metal plating layer or a sputtered metal layer on the underlayer or the bonding layer, and a step of forming an electrolytic metal plating layer on the electroless metal plating layer or the sputtered metal layer,
the root mean square roughness (Rms) and the arithmetic mean roughness (Ra) of the metal layer lamination surface of the resin film are both 50 nm or less;
The 180° peel strength between the metal layer and the resin film is 1.0 N/mm or more ;
The method for producing a metal-clad laminate , wherein the resin film is a cycloolefin polymer film or a cycloolefin copolymer substrate . The method for producing a metal-clad laminate according to claim 7 , wherein the root mean square roughness (Rms) and arithmetic mean roughness (Ra) of the metal layer laminate surface of the resin film after removing the metal layer from the metal-clad laminate are both 50 nm or less. Both surfaces of the resin film are the metal layer lamination surfaces,
The method for producing a metal-clad laminate according to claim 7 or 8 , wherein in the step of forming the metal layer, the metal layer is formed on each of the two metal layer lamination surfaces without using the adhesive. a pattern having recesses and protrusions is formed on the metal layer lamination surface of the resin film,
The method for producing a metal-clad laminate according to any one of claims 7 to 9 , wherein in the step of forming the metal layer, the metal layer is formed so as to fill the recesses and cover the protrusions of the pattern. A method for producing a wiring board, comprising the step of forming a wiring layer by etching the metal layer of the metal-clad laminate produced by the method for producing a metal-clad laminate according to any one of claims 7 to 9 . The method for manufacturing a wiring board according to claim 11 , wherein the resin film exposed after etching the metal layer has a root mean square roughness (RMS) and an arithmetic mean roughness (Ra) of 50 nm or less. 13. The method for manufacturing a wiring board according to claim 11 , wherein the haze of the resin film exposed after etching the metal layer is 0.1 to 0.5. A method for manufacturing a wiring board, comprising the step of forming a wiring layer by chemically and 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 method for manufacturing a metal-clad laminate according to claim 10. A step of forming a resist pattern having an opening on the metal layer of the metal-clad laminate produced by the method for producing a metal-clad laminate according to any one of claims 7 to 9 ;
forming a metal wiring layer in the opening of the resist pattern; and removing the resist pattern.
and etching the metal layer exposed by removing the resist pattern.

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