Printed wiring board manufacturing method and printed wiring board

Abstract

This method for manufacturing a printed wiring board comprises: a step for preparing a metal foil-clad laminate in which a metal foil having an arbitrary thickness (Db) in a range of from 3 to 20 μm and an insulating resin layer are laminated; a step for forming a resist layer on a surface of the metal foil; a step for forming a resist pattern by subjecting the resist layer to exposure / development; a step for forming metal wires by etching the metal foil where the resist pattern is not formed by spraying an etching solution; and a step for removing the resist layer. In the step for forming the metal wires, the metal wires are formed such that the metal wires have a gap (S) of 15 to 50 μm, and that a ratio (S / Db) of an arbitrary thickness (Db) of the metal foil and the gap (S) between the metal wires is greater than 1.6.

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a printed wiring board, and a printed wiring board. [Background technology]

[0002] Printed wiring boards and semiconductor element mounting substrates, which are widely used in electronic devices, communication devices, personal computers, etc., usually have an insulating resin layer and a conductor layer having a wiring pattern formed on the insulating resin layer. Due to the increase in the number of wirings associated with the high functionality of electronic devices, etc., and the miniaturization of electronic devices, etc., there is a demand for finer metal wiring patterns. As a method for forming a metal wiring pattern, a subtractive method, etc. is known, and an example of the subtractive method is a method of forming a metal wiring pattern by selectively removing a conductor layer using an etching resist. As an etching method in the subtractive method, there is wet etching. In wet etching, an etching solution penetrates into the conductor layer through an opening in a resist pattern, thereby etching the conductor layer.

[0003] Patent Document 1 describes a method for producing a wired circuit board using wet etching in a subtractive method.

[0004] Patent Document 2 also describes the following method for forming an electronic circuit. That is, in a method for forming an electronic circuit by etching a copper-clad laminate, first, a layer of nickel or nickel alloy with a slow etching rate is formed on the etching surface side of a copper layer made of rolled copper foil or electrolytic copper foil. Then, the non-etching side surface of the copper layer is attached to a resin substrate to form a copper-clad laminate, and then a resist pattern for forming a circuit is applied on the copper layer and nickel or nickel alloy layer formed. Furthermore, an etching solution made of a ferric chloride solution is used to remove unnecessary parts of the copper layer and nickel or nickel alloy layer on the copper-clad laminate other than the part where the resist pattern is applied. Then, the resist is removed, and the remaining nickel layer is removed by soft etching to form a circuit, and a method for forming an electronic circuit is described. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-125560 A [Patent Document 2] Republished Patent 2010-074054 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the formation of a metal wiring pattern, in the subtractive etching, the metal part of the metal foil wiring after etching is etched in a widening manner from the surface of the metal foil toward the insulating resin layer, so-called "sagging" occurs, making it difficult to form fine wiring with uniform gaps between the metal wiring. Furthermore, in a wiring circuit board where "sagging" occurs, the wiring may short-circuit near the insulating resin layer.

[0007] In this regard, the method for producing a wired circuit board described in Patent Document 1 makes it possible to form fine wiring. However, the method described in Patent Document 1 requires two wet etching steps, one for forming a patterned conductor layer from a conductor layer by wet etching, and the other for obtaining a wired circuit board by wet etching. This makes the process complicated, lengthens the time required to produce the wired circuit board, and reduces productivity.

[0008] Furthermore, in the method for forming an electronic circuit described in Patent Document 2, the resist layer and the layer made of nickel or a nickel alloy and having a slow etching rate cannot be completely removed by soft etching in the step of forming the electronic circuit, and some of them remain undissolved. Therefore, even in the method of Patent Document 2, it is difficult to form fine wiring with uniform gaps between metal wirings. In addition, although a ferric chloride solution is used as a soft etching solution, the ferric chloride cannot be completely removed and remains, which causes a problem of migration.

[0009] The present invention has been made in consideration of such problems, and has an object to provide a method for manufacturing a printed wiring board, which is capable of manufacturing a printed wiring board having uniform gaps between metal wiring and fine wiring with high productivity, and the printed wiring board. [Means for solving the problem]

[0010] As a result of intensive research to solve the above problems, the present inventors have discovered that, in a method for manufacturing a printed wiring board using a subtractive method, an etching solution is sprayed by a spray to reduce the gap (S) between metal wirings and the thickness (D) of a metal foil on which the metal wiring is formed. b ) to the gap between metal wiring (S) (S / D b The inventors have found that the above-mentioned problems can be solved by a manufacturing method including a step of forming metal wiring by etching the metal foil in a portion where a resist pattern is not formed so that the above-mentioned properties, , and , respectively, are within specific ranges, and have thus completed the present invention.

[0011] That is, the present invention is as follows. [1] Any thickness (D) in the range of 3 to 20 μm b preparing a metal foil-clad laminate in which a metal foil having the above-mentioned structure and an insulating resin layer are laminated; forming a resist layer on the surface of the metal foil; a step of exposing and developing the resist layer to form a resist pattern; a step of forming metal wiring by spraying an etching solution onto the metal foil in a portion where the resist pattern is not formed; removing the resist layer; In the step of forming the metal wiring, the gap (S) between the metal wirings is 15 to 50 μm, and the thickness (D b ) to the gap (S) between the metal wirings (S / D b ) exceeds 1.6.

[0012] [2] The method for manufacturing a printed wiring board according to [1], wherein the etching is carried out by spraying air together with the etching solution using a spray. [3] The method for producing a printed wiring board according to [1] or [2], wherein in the step of forming the resist pattern, a gap (R) between the resist patterns is formed to be 1 to 5 μm narrower than a gap (S) between the metal wirings. [4] The method for producing a printed wiring board according to any one of [1] to [3], wherein the printed wiring board has two or more consecutive gaps (US) having the same width as the gaps (S) between the metal wirings among the gaps (U) formed in the metal foil. [5] In the step of forming the metal wiring, the width (W b ) and the gap (S) between the metal wirings are the same ((W b The method for producing a printed wiring board according to any one of [1] to [4], wherein the wiring board is formed so that (S)=(S).

[0013] [6] In the step of preparing the metal foil-clad laminate, the metal foil is formed to have any thickness (D b The method for producing a printed wiring board according to any one of [1] to [5], wherein the metal foil is obtained by adjusting the thickness of the metal foil so that [7] The method for producing a printed wiring board according to any one of [1] to [6], wherein the resist layer formed on the surface of the metal foil has a thickness of 15 μm or less. [8] The method for producing a printed wiring board according to any one of [1] to [7], wherein in the step of forming the metal wiring, the metal wiring is formed so that the length (L) of the metal wiring is 100 μm or more. [9] The method for producing a printed wiring board according to any one of [1] to [8], wherein the metal foil is a copper foil.

[0014]

[10] An insulating resin layer and a metal wiring laminated on the insulating resin layer, The thickness (D) of the metal wiring is 3 to 20 μm, The gap (U) between the metal wirings is 12 to 50 μm, The width (W) of the metal wiring is 12 to 50 μm, The ratio (U / D) of the thickness (D) of the metal wiring to the gap (U) between the metal wirings is 1.0 or more; The average thickness of the metal wiring (D ave ) and the average gap between the metal lines (U ave ) and the ratio (U ave / D ave ) is 1.60 to 1.80, The ratio (W / D) of the thickness (D) of the metal wiring to the width (W) of the metal wiring is 1.0 or more, and The average thickness of the metal wiring (D ave ) and the average width (W ave ) and the ratio (W ave / D ave ) is 1.60 to 1.80. Effect of the Invention

[0015] According to the manufacturing method of the present invention, a printed wiring board having fine wiring with uniform gaps between the metal wirings can be manufactured with high productivity. Also, according to the present invention, a printed wiring board having fine wiring with uniform gaps between the metal wirings can be provided. [Brief description of the drawings]

[0016] [Figure 1] 1A to 1C are schematic diagrams illustrating a method for manufacturing a printed wiring board according to an embodiment of the present invention. [Diagram 2] 2 is a schematic diagram showing a gap (R) between resist patterns in the step of forming a resist pattern of the present embodiment. FIG. [Diagram 3] 1 is a schematic diagram showing the gap (S) between metal wirings, the arbitrary thickness (Db and D) of the first metal foil, and the width (Wb and W) of the metal wirings of the first metal foil in the process of forming the metal wirings of this embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a detailed description will be given of an embodiment of the present invention (hereinafter, simply referred to as "the present embodiment") with reference to the drawings as necessary, but the present invention is not limited to the present embodiment. The present invention can be modified in various ways without departing from the gist of the invention. In the drawings, the same elements are given the same reference numerals, and duplicated explanations are omitted. Furthermore, unless otherwise specified, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the illustrated ratios. In this specification, a laminate is one in which each layer is bonded to another, but the layers may be layers that can be peeled off from each other as necessary.

[0018] The method for producing a printed wiring board and the printed wiring board will be described with reference to Figures 1 to 3. Figure 1 is a schematic diagram showing the method for producing a printed wiring board in this embodiment. [Method for manufacturing printed wiring board] The method for producing a printed wiring board according to the present embodiment is as shown in FIG. Any thickness (D) in the range of 3 to 20 μm b preparing a metal foil-clad laminate in which a metal foil having the above-mentioned structure and an insulating resin layer are laminated; forming a resist layer on the surface of the metal foil; a step of exposing and developing the resist layer to form a resist pattern; a step of forming metal wiring by spraying an etching solution onto the metal foil in a portion where the resist pattern is not formed; removing the resist layer; In the step of forming the metal wiring, the gap (S) between the metal wirings is 15 to 50 μm, and the thickness (D b ) to the gap (S) between the metal wirings (S / D b The metal wiring is formed so that the difference between the resistance and the resistivity exceeds 1.6.

[0019] According to the method for manufacturing a printed wiring board, a printed wiring board having fine wiring with uniform gaps between metal wirings can be manufactured with high productivity.

[0020] (Any thickness (D) in the range of 3 to 20 μm b A step of preparing a metal foil-clad laminate in which a metal foil having the above-mentioned properties and an insulating resin layer are laminated together. FIG. 1(a) is a schematic diagram showing a metal foil-clad laminate in which a first metal foil 11, an insulating resin layer 10, and a second metal foil 12 are laminated in this order. In this embodiment, the metal foil 11 is laminated to any thickness (D b A metal foil-clad laminate is prepared in which a metal foil having the above-mentioned structure and an insulating resin layer are laminated together.

[0021] (Metal foil laminate) As shown in Fig. 1(a), the metal foil laminate can be made with any thickness (D b) and an insulating resin layer 10 laminated in this order can be used. As shown in Fig. 1(a), the metal foil clad laminate 21 may have a second metal foil 12 laminated on the surface of the insulating resin layer 10 opposite to the surface on which the first metal foil 11 is laminated.

[0022] Metal foil The first metal foil 11 can be formed to any thickness (D b ) with any thickness (D b ) is preferably a uniform thickness. In this case, the thickness variation is calculated using the average thickness, maximum thickness, and minimum thickness of the first metal foil 11, and an arbitrary thickness (D b ) is preferably in the range of 0 to 25% of the average thickness. b Regarding the first metal foil 11, for example, when copper foil is used as the metal foil, the thickness can be measured using a surface copper film thickness meter (Model 700 (product name)) manufactured by Oxford Instruments. For other metal foils, the thickness can be measured using, for example, a fluorescent X-ray film thickness meter (SFT3400 (product name)) manufactured by Hitachi High-Tech Science Corporation. By using such a first metal foil 11, it is possible to obtain a printed wiring board having fine wiring with uniform gaps between the metal wirings.

[0023] Any thickness (D b ) can be adjusted by a known method. For example, the surface of the first metal foil 11 can be etched to an arbitrary thickness (D b ) can also be obtained by etching.

[0024] The second metal foil 12 may have any thickness (d b ) is preferably used. bIt is more preferable that the thickness (d ) is uniform. In this case, it is more preferable that the thickness variation is 0 to 25% of the average thickness of the second metal foil 12. b ) is measured in the same manner as described above. The thicknesses of the first metal foil 11 and the second metal foil 12 may be the same or different on both sides, but are preferably the same. The thickness of the second metal foil 12 can be adjusted in the same manner as the thickness adjustment of the first metal foil 11 described above.

[0025] Examples of the first metal foil 11 and the second metal foil 12 include gold, silver, copper, aluminum, and alloys of two or more of these metals. Copper is preferable in terms of electrical conductivity. The first metal foil 11 and the second metal foil 12 may be the same or different, but are preferably the same.

[0026] As the first metal foil 11 and the second metal foil 12, for example, commercially available products such as GHY5 (trade name, 12 μm thick copper foil) and JXUT-1 (trade name, 1.5 μm thick copper foil) manufactured by JX Metals Corporation, 3EC-M2S-VLP (trade name, 12 μm thick copper foil), 3EC-VLP (trade name, 12 μm thick copper foil) and 3EC-III (trade name, 12 μm thick copper foil) manufactured by Mitsui Mining & Smelting Co., Ltd., and GTS-MP (trade name, 12 μm thick copper foil) manufactured by Furukawa Electric Co., Ltd. can also be used.

[0027] Insulating resin layer The insulating resin layer 10 usually contains a thermosetting resin, an inorganic filler, and, if necessary, a glass cloth. The thickness of the insulating resin layer 10 is usually 1 to 200 μm, and preferably 1 to 100 μm from the viewpoint of ease of handling of the base material.

[0028] The thermosetting resin is not particularly limited as long as it is a thermosetting resin used in printed wiring board materials. Specific examples include compounds such as cyanate ester compounds, epoxy resins, maleimide compounds, polyimide resins, and double bond-added polyphenylene ether resins. These can be appropriately selected according to the intended use and performance, and can be used alone or in combination of two or more. Preferred thermosetting resins include cyanate ester compounds and epoxy resins.

[0029] The cyanate ester compound is not particularly limited as long as it is a compound having two or more cyanate groups in one molecule. Specific examples include bisphenol A type cyanate ester compounds, phenol novolac type cyanate ester compounds, bisphenol E type cyanate ester compounds, naphthalene skeleton-containing cyanate ester compounds, and biphenyl skeleton-containing cyanate ester compounds. These can be appropriately selected according to the intended use and performance, and can be used alone or in combination of two or more. Preferred cyanate ester compounds include 2,2-bis(4-cyanatophenyl)propane, bis(3,5-dimethyl-4-cyanatophenyl)methane, phenol novolac type cyanate ester compounds, and naphthol aralkyl type cyanate ester compounds.

[0030] The epoxy resin is not particularly limited as long as it is a compound having two or more epoxy groups in one molecule. Specific examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenol type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, multifunctional phenol type epoxy resin, naphthalene skeleton-containing epoxy resin, biphenyl skeleton-containing epoxy resin, and phosphorus-containing epoxy resin. These can be appropriately selected according to the intended use and performance, and can be used alone or in combination of two or more. Preferred epoxy resins include bisphenol A type epoxy resin, phenol novolac type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene type epoxy resin, naphthol aralkyl type epoxy resin, and trifunctional phenol type epoxy resin.

[0031] The maleimide compound is not particularly limited as long as it has two or more maleimide groups in one molecule. Specific examples include bis(4-maleimidophenyl)methane, 2,2-bis{4-(4-maleimidophenoxy)-phenyl}propane, bis(3,5-dimethyl-4-maleimidophenyl)methane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, bis(3,5-diethyl-4-maleimidophenyl)methane, and polyphenylmethane maleimide. These maleimide compounds can also be blended in the form of a prepolymer, or a prepolymer of a maleimide compound and an amine compound. These can be appropriately selected depending on the intended use and performance, and can be used alone or in combination of two or more. A preferred maleimide compound is bis(3-ethyl-5-methyl-4-maleimidophenyl)methane.

[0032] As the polyimide resin, generally known ones can be used. Specific examples include reaction products of polyfunctional maleimides and polyamines, and polyimides having a terminal triple bond as described in JP-B-57-005406. These polyimide resins can be used alone or in combination of two or more kinds.

[0033] As the double bond-added polyphenylene ether resin, poly(2,6-dimethyl-1,4-phenylene ether) or a random copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol is used in combination with an unsaturated fatty acid carboxylic acid or its unsaturated fatty acid. water These double bond-added polyphenylene ether resins can be used alone or in combination of two or more.

[0034] As the inorganic filler, metal oxides, nitrides, silicides, borides, etc., such as silica, boron nitride, wollastonite, talc, kaolin, clay, mica, alumina, zirconia, titania, barium titanate, and magnesium oxide can be used. These can be appropriately selected depending on the intended use and performance, and one or more types can be used in combination. By including an inorganic filler, it is possible to reduce the thermal expansion coefficient and improve the rigidity of the printed wiring board. In particular, by adding an inorganic filler with a low dielectric constant such as silica, boron nitride, and barium titanate, it is possible to reduce the dielectric constant of the insulating resin layer 10.

[0035] Examples of the glass cloth that can be used include E glass cloth, NE glass cloth, D glass cloth, T glass cloth, Q glass cloth, and quartz glass cloth. These glass cloths can be used alone or in combination of two or more kinds.

[0036] As the insulating resin layer 10, for example, a commercially available product such as GHPL-830NX A-IT56 (product name, thickness: 100 μm) manufactured by Mitsubishi Gas Chemical Company, Inc. may be used.

[0037] As the metal foil-clad laminate 21, for example, commercially available products such as HL-830NS (product name), HL-830 NXA (product name), and HL-830 NSF (product name) manufactured by Mitsubishi Gas Chemical Company, Inc. can also be used.

[0038] ·Adhesive layer In this embodiment, an adhesive layer for adhering the first metal foil 11 or the second metal foil 12 to the insulating resin layer 10 may be provided between them, or a metal foil with an adhesive layer may be used. The adhesive layer may be made of, for example, an acrylic resin, an epoxy resin, a polyimide resin, or a polyester resin.

[0039] Metal foil resin sheet In this embodiment, a resin sheet with metal foil may be used in which a metal foil and an insulating resin layer are laminated in this order. Alternatively, a metal foil-clad laminate in which a first metal foil 11 and a second metal foil 12 are laminated on both sides of the insulating resin layer 10 by laminating a metal foil on the surface of the insulating resin layer of the resin sheet may be used. board 21 may also be used. As the resin sheet with metal foil, for example, a commercially available product such as CRS-381NS1 (product name, resin sheet with copper foil) manufactured by Mitsubishi Gas Chemical Company, Inc. may also be used.

[0040] Metal foil laminate board The thickness of 21 is usually 3 to 236 μm, preferably 3 to 224 μm, more preferably 3 to 136 μm, and further preferably 3 to 124 μm.

[0041] (Drilling and plating process) 1(b) is a schematic diagram showing a metal foil-clad laminate 22 in which a first metal foil 11 and a second metal foil 12 are electrically connected. In this embodiment, the metal foil-clad laminate 21 is subjected to via-hole and / or through-hole drilling processing as necessary, for example, as shown in FIG. 1(b), the first metal foil 11 and the second metal foil 12 are electrically connected, and a laminate having an arbitrary thickness (D b The first metal foil 11 has a thickness of d b In this embodiment, the metal foil-clad laminate 22 may be adjusted to have an arbitrary thickness (D b ) and an insulating resin layer may be laminated together to form a metal foil-clad laminate.

[0042] When using the metal foil-clad laminate 21, after metal plating, the first metal foil 11 is laminated to a desired thickness (D b ), and the thickness of the second metal foil 12 is adjusted to an arbitrary thickness (d b ), it is preferable to etch the surface of the first metal foil 11 and, if necessary, the surface of the second metal foil 12 using a soft etching solution of perhydrate / sulfuric acid such as SE-07 (product name) manufactured by Mitsubishi Gas Chemical Company, Inc. and CPE-700 (product name) manufactured by Mitsubishi Gas Chemical Company, Inc. In this case, it is more preferable to etch the first metal foil 11 and the second metal foil 12 in advance so that their thicknesses are both within the range of 3 to 20 μm.

[0043] The hole drilling is usually performed using a mechanical drill, a carbon dioxide laser, a UV laser, a YAG laser, or the like.

[0044] When the hole drilling process is performed, a roughening process including a desmear process may be performed thereafter. The roughening process usually includes a swelling process, a surface roughening and smear dissolving process, and a neutralization process.

[0045] The swelling step is performed by swelling the surface of the insulating resin layer using a swelling agent. The swelling agent is not particularly limited as long as it can improve the wettability of the surface of the insulating resin layer and swell the surface of the insulating resin layer to such an extent that oxidative decomposition is promoted in the subsequent surface roughening and smear dissolving steps. Examples of the swelling agent include an alkaline solution and a surfactant solution.

[0046] The surface roughening and smear dissolving process is carried out using an oxidizing agent. Examples of the oxidizing agent include an alkaline permanganate solution. Suitable specific examples include an aqueous potassium permanganate solution and an aqueous sodium permanganate solution. Such an oxidizing agent treatment is called wet desmear, but in addition to the wet desmear, other known roughening treatments such as dry desmear by plasma treatment or UV treatment, mechanical polishing by buffing, sandblasting, etc. may be appropriately combined.

[0047] In the neutralization step, the oxidizing agent used in the previous step is neutralized with a reducing agent. The reducing agent may be an amine-based reducing agent, and specific examples of suitable reducing agents include acidic aqueous solutions such as an aqueous solution of hydroxylamine sulfate, an aqueous solution of ethylenediaminetetraacetic acid, and an aqueous solution of nitrilotriacetic acid.

[0048] After providing the via holes and / or through holes, or after desmearing the inside of the via holes and / or through holes, it is preferable to perform a metal plating process to electrically connect the conductor layers. In this embodiment, the first metal foil 11 laminated on the metal foil-clad laminate 21 and, if necessary, the second metal foil 12 (both the metal foil 11 and the metal foil 12 may be the metal foils after the etching) may be directly subjected to a metal plating process without providing the via holes and / or through holes.

[0049] The metal plating method may be a method for metal plating used in the manufacture of a normal multilayer printed wiring board. The metal plating method and the type of chemical used for plating may be a method for metal plating used in the manufacture of a normal multilayer printed wiring board. The chemical used for metal plating may be a commercially available product.

[0050] Examples of metal plating methods include treatment with a degreasing liquid, treatment with a soft etching liquid, acid washing, treatment with a pre-dip liquid, treatment with a catalyst liquid, treatment with an accelerator liquid, treatment with a chemical copper liquid, acid washing, and treatment of immersion in a copper sulfate liquid and passing an electric current through it.

[0051] A specific example of the metal plating method is a method in which an electroless plating film is formed on the inner wall of a via hole and / or an inner wall of a through hole by a normal electroless plating process, and then the inside of the via hole and / or the through hole is filled with plating by an electrolytic plating method such as a sparger plating method in which a plating solution is jetted and thrown against a metal foil-clad laminate. As the electroless plating or electrolytic plating, for example, metal plating of copper, tin, silver, various solders, copper and tin, copper and silver, etc. is preferable, and electroless copper plating or electrolytic copper plating is more preferable. For specific methods, see the Examples.

[0052] The thicknesses of the first metal foil 11 and the second metal foil 12 obtained by the metal plating treatment may be the same or different on both sides, but are preferably the same. The thicknesses of the first metal foil 11 and the second metal foil 12 obtained by the metal plating treatment can be adjusted to any thickness (D b ) and any thickness (d b In this case, the thickness of the first metal foil 11 is adjusted to an arbitrary thickness (D b The thickness (d) of the second metal foil 12 is the sum of the thickness of the metal foil laminated on the metal foil-clad laminate 21 (which may be the thickness of the metal foil after the etching) and the thickness of the metal-plated layer. b The preferred ranges for the thicknesses of the first metal foil 11 and the second metal foil 12 are the same as those described above.

[0053] (A process for forming a resist layer on the surface of metal foil) Fig. 1(c) is a schematic diagram showing a metal foil-clad laminate 23 on which a first resist layer 13 and a second resist layer 14 are formed. In this embodiment, as shown in Fig. 1(c), a step of forming a first resist layer 13 on the surface of a first metal foil 11 is included. Through this step, a metal foil-clad laminate 23 on which the first resist layer 13 is formed on the surface of the first metal foil 11 can be obtained. The first resist layer 13 is applied to the entire metal foil-clad laminate 21 or the metal foil-clad laminate 22 so as to cover the first metal foil 11 in the metal foil-clad laminate 21 or the metal foil-clad laminate 22. If necessary, a second resist layer 14 may be formed on the surface of the second metal foil 12 in the same manner as the first resist layer 13. In this embodiment, before the first resist layer 13 and the second resist layer 14 are formed, alignment holes, which will be described later, may be provided.

[0054] It is preferable to use a resist having excellent developability as a material for forming the first resist layer 13. As such a resist, a commercially available product can be used. For example, RD-1225 (product name), RD-1215 (product name), RY-5319 (product name), RD-2010 (product name), and RY-5115 (product name) manufactured by Hitachi Chemical Co., Ltd. can be mentioned. The same material can also be used for the second resist layer 14.

[0055] The thickness of the first resist layer 13 and the second resist layer 14 is not particularly limited as long as the first metal foil 11 and the second metal foil 12 can be dissolved and removed by etching. The thickness of the first resist layer 13 and the second resist layer 14 is preferably 15 μm or less, more preferably 1 to 13 μm, and even more preferably 1 to 10 μm, in order to obtain a better resolution. The thickness of the first resist layer 13 and the second resist layer 14 may be the same or different, but is preferably the same.

[0056] A known method used in the manufacture of printed wiring boards can be used to form the first resist layer 13 and the second resist layer 14. For example, the first resist layer 13 and the second resist layer 14 can be formed by a subtractive method described below.

[0057] (A process of forming a resist pattern by exposing and developing the resist layer) Fig. 1(d) is a schematic diagram showing a metal foil-clad laminate 24 in which a resist pattern is formed on each of the first resist layer 13 and the second resist layer 14. In this embodiment, as shown in Fig. 1(d), a process is included in which the first resist layer 13 is exposed and developed to form a resist pattern. Through this process, a metal foil-clad laminate 24 in which a resist pattern is formed on the first resist layer 13 can be obtained. The resist pattern is formed at an appropriate position along the wiring pattern.

[0058] In this embodiment, the gap (R) between the resist patterns is preferably formed to be 1 to 5 μm narrower than the gap (S) between the metal wirings described below, and more preferably 2 to 4 μm narrower, taking into consideration the effect of etching on the width direction of the metal wiring. The gap (R) between the resist patterns means the width 41 of the gap between the resist patterns as shown in FIG. 2, and it is preferable to form the resist pattern in the first resist layer 13 so as to have the gap (R). Similarly, in consideration of the effect of etching on the width direction of the metal wiring, the gap (r) between the resist patterns is preferably formed to be 1 to 5 μm narrower than the gap (s) between the metal wiring described below, and more preferably 2 to 4 μm narrower. The gap (r) between the resist patterns, like the gap (R) between the resist patterns, means the width of the gap between the resist patterns, and it is preferable to form the resist pattern in the second resist layer 14 so as to have the gap (r). The method for measuring the gap (R) and (r) between the resist patterns is the same as that for the thickness (D b ) and (d b ) and the Examples.

[0059] In this embodiment, if necessary, a resist pattern may be formed by exposing and developing the second resist layer 14 in the same manner as the resist pattern for the first resist layer 13. In this case, the resist pattern is formed at an appropriate position along the wiring pattern.

[0060] The first resist layer 13 and the resist pattern can be formed by the subtractive method, for example, as follows. A dry film resist (e.g., RD-1225 (trade name) and RD-2010 (trade name) manufactured by Hitachi Chemical Co., Ltd.) is laminated (laminated) on the surface of the first metal foil 11 and, if necessary, on the surface of the second metal foil 12 at a temperature of 110±10° C. and a pressure of 0.50±0.02 MPa to form the first resist layer 13 and, if necessary, the second resist layer 14. Next, the first resist layer 13 is exposed along the circuit pattern and masked. If necessary, the second resist layer 14 is also exposed along the circuit pattern and masked. Thereafter, the dry film resist is developed with a 1% aqueous solution of sodium carbonate to form a resist pattern on the first resist layer 13. If necessary, the dry film resist is developed with a 1% aqueous solution of sodium carbonate to form a resist pattern on the second resist layer 14. In this way, a metal foil-clad laminate 24 having a resist pattern formed thereon can be formed.

[0061] In this embodiment, it is preferable to form a resist pattern by a spray method in which a developing solution such as an aqueous solution of sodium carbonate and an aqueous solution of potassium carbonate is sprayed onto a dry film resist, as shown in FIG. 1(d), in order to shorten the manufacturing time of the wiring circuit board and obtain good productivity.

[0062] The spray may be a known one used in the manufacture of printed wiring boards. In this embodiment, since a printed wiring board having uniform gaps between metal wirings and fine wiring can be manufactured with high productivity and a resist pattern of fine lines can be formed, it is more preferable to spray air together with the developer by spraying to form a resist pattern. The spraying is preferably performed at a spray pressure of the developing device of 0.05 to 1.5 MPa and for a spraying time of 10 to 120 seconds. In addition, the spray pressure of the developing device is preferably 0.07 to 1.2 MPa. The spraying time is preferably 20 to 100 seconds.

[0063] As a spray for spraying air together with the developer, for example, a spray having a two-fluid nozzle is preferable.

[0064] (A process in which an etching solution is sprayed onto the metal foil in areas where the resist pattern is not formed, forming metal wiring.) FIG. 1(e) is a schematic diagram showing a metal foil-clad laminate 25 in which metal wiring is formed on each of a first metal foil 11 and a second metal foil 12. In this embodiment, as shown in FIG. 1(e), a step of forming metal wiring on the first metal foil 11 is included, by spraying an etching solution onto the first metal foil 11 in a portion where a resist pattern is not formed. In the step of forming metal wiring, a gap (S) between the metal wirings is set to 15 to 50 μm, and the first metal foil 11 has an arbitrary thickness (D b ) to the gap between metal wiring (S) (S / D b ) exceeds 1.6. By going through this process, it is possible to obtain a metal foil-clad laminate 25 on which metal wiring is formed. Furthermore, by having this process, it is possible to obtain a printed wiring board having uniform gaps between the metal wirings and fine wiring.

[0065] The gap (S) between the metal wirings means a width 42 in the gap between the metal wirings as shown in FIG. 3, and this width 42 is in the range of 15 to 50 μm. In this embodiment, the metal wirings are formed in the first metal foil 11 so as to have a gap (S). In this embodiment, the metal wirings may be formed so as to have a gap between the metal wirings having a width other than the gap (S), that is, a gap between the metal wirings having a width less than 15 μm and / or more than 50 μm. Regarding the lower and upper limits of the width of this gap, the lower limit is usually 10.5 μm and the upper limit is usually 1,000 μm. From the viewpoint of high density wiring, the gap (S) between the metal wirings is preferably formed so as to be 15 to 35 μm. In this case, the metal wirings may be formed so as to have a gap between the metal wirings having a width less than 15 μm and / or more than 35 μm. In this embodiment, the metal wiring may be formed on the second metal foil 12 so as to have a gap (s) similar to the gap (S) between the metal wirings. The gap (s) between the metal wirings means the width of the gap between the metal wirings formed on the second metal foil 12, and this width is usually preferably 15 to 50 μm. In this embodiment, the metal wiring may be formed so as to have a gap between the metal wirings having a width other than the gap (s), that is, a gap between the metal wirings having a width less than 15 μm and / or more than 50 μm. Regarding the lower and upper limits of the width of this gap, the lower limit is usually 10.5 μm and the upper limit is 1000 μm. From the viewpoint of high density wiring, the gap (s) between the metal wirings is preferably formed so as to have a width of 15 to 35 μm. In this case, the metal wirings may be formed so as to have a gap between the metal wirings having a width less than 15 μm and / or more than 35 μm. The method for measuring the gap (S) and (s) between the metal wirings is described in the above-mentioned thickness (D b ) and (d b ) and the Examples.

[0066] Any thickness (D b ) is an insulating resin, as shown in Figure 3. layer 10 to the first metal foil 11. b ) and the preferred ranges are as described above. Similarly, the thickness (d b ) is an insulating resin layer The thickness of the second metal foil 12 from the surface of the first metal foil 10 is an arbitrary thickness (d b ) and the preferred ranges are as described above.

[0067] Any thickness (D b ) to the gap between metal lines (S) (S / D b The metal wiring is formed so that the ratio (S / D) exceeds 1.6, preferably 1.6 to 3.0, and more preferably 1.6 to 2.5. bBy forming the metal wiring so that the thickness of the wiring is within the above range, etching between the wirings is sufficient, which allows for high-density wiring and reduces the occurrence of insulation defects such as short circuits. Similarly, the thickness (d b ) to the gap between metal lines (s) (s / d b It is preferable to form the metal wiring so that the ratio (s / d) exceeds 1.6, it is more preferable to form the metal wiring so that the ratio is 1.6 to 3.0, and it is even more preferable to form the metal wiring so that the ratio is 1.6 to 2.5. b By forming the metal wiring so that the thickness of the wiring is within the above range, etching between the wirings is sufficient, which allows for high-density wiring and reduces the occurrence of insulation defects such as short circuits.

[0068] In the process of forming the metal wiring, in order to increase the density of the metal wiring that transmits electric signals, the width (W b ) and the gap (S) between the metal wirings are the same ((W b It is preferable to form the metal wiring so that the width (W) of the metal wiring is equal to the width (S) of the metal wiring. b ) means the width 44 of the metal wiring as shown in FIG. 3, and this width (W b It is preferable that metal wiring is formed on the first metal foil 11 so as to have a cross section of the first metal foil 11 . Similarly, the width (w b ) and the gap (s) between the metal wirings are the same ((w b It is preferable to form the metal wiring so that the width (w b ) is the width of the metal wiring (W b ), it means the width of the metal wiring, and this width (w b It is preferable that the metal wiring is formed on the second metal foil 12 so as to have a width (W b ) and (w b The method for measuring the thickness (Db ) and (d b ) and the Examples.

[0069] In the step of forming the metal wiring, if a long wiring can be formed, it becomes easy to lay out the wiring to pads, via holes, etc., and the degree of freedom in design is increased, so it is preferable to form the metal wiring on the first metal foil 11 so that the length (L) of the metal wiring in the longitudinal direction is 100 μm or more. The upper limit is, for example, 10 mm. Similarly, it is preferable to form the metal wiring on the second metal foil 12 so that the length (l) of the metal wiring in the longitudinal direction is 100 μm or more, since forming a long wiring makes it easier to route the wiring to pads, via holes, etc., and increases the degree of freedom in design. The upper limit is, for example, 10 mm. The method for measuring the length (L) and (l) of the metal wiring in the longitudinal direction is the same as that for the thickness (D b ) and (d b ) and the Examples.

[0070] In this embodiment, if necessary, a second metal foil 1 2 In this case, metal wiring may be formed in the same manner as in the first metal foil 11.

[0071] The metal wiring can be formed, for example, as follows. As shown in FIG. 1(e), the first metal foil 11 and the second metal foil 12 in the first resist layer 13 and, if necessary, the second resist layer 14, in the portions where the resist pattern is not formed, are etched to remove the metal foil. The etching is performed by spraying an etching solution. By performing etching with a spray, etching is not spread out from the metal foil toward the insulating resin layer, and so-called "sagging" does not occur, so that it is possible to form fine wiring with uniform gaps between the metal wirings.

[0072] The spray may be a known one used in the manufacture of printed wiring boards. In this embodiment, it is preferable to spray air together with the etching solution by spraying, since it is possible to manufacture printed wiring boards having uniform gaps between metal wirings and fine wiring with high productivity. It is preferable that the spraying is performed at an etching rate of 0.05 to 1.5 μm / sec for a spraying time of 20 to 120 seconds. The etch rate is described as the amount of etching per unit time in the thickness direction when etching a metal foil with a spray.

[0073] A preferred spray for spraying air together with the etching solution is, for example, a spray having a two-fluid nozzle. The flow rate of the etching solution in the two-fluid nozzle is preferably 0.5 to 3.5 L / min, more preferably 1.5 to 2.5 L / min. The flow rate of the air is preferably 100 to 400 L / min, more preferably 200 to 300 L / min.

[0074] The etching solution may be any known solution used in the manufacture of printed wiring boards, such as an aqueous solution of cupric chloride (a mixed solution of copper concentration: 120 to 180 g / L and hydrochloric acid concentration: 100 to 150 g / L).

[0075] (Step of removing the resist layer) Fig. 1(f) is a schematic diagram showing a metal foil-clad laminate 26 from which the first resist layer 13 and the second resist layer 14 have been removed. In this embodiment, as shown in Fig. 1(f), a step of removing the first resist layer 13 is included. Through this step, it is possible to obtain the metal foil-clad laminate 26 from which the first resist layer 13 has been removed. When the second resist layer 14 has been formed, the second resist layer 14 is removed to obtain the metal foil-clad laminate 26.

[0076] The first resist layer 13 and the second resist layer 14 can be removed by a known method used in the manufacture of printed wiring boards, and are not particularly limited. For example, a method of stripping off a dry film resist using an aqueous potassium hydroxide solution and an amine-based resist stripping solution can be used.

[0077] (Step of Providing Via Holes and / or Through Holes) In this embodiment, a process of drilling via holes and / or through holes may be included as necessary to electrically connect each metal foil (conductor layer). In addition, when drilling is performed, a roughening process including a desmear process may be performed after that. For the drilling process and the roughening process, refer to the above. After providing the via holes and / or through holes, or after desmearing the inside of the via holes and / or through holes, it is preferable to perform a metal plating process to electrically connect the conductor layers. For the metal plating process, see the above.

[0078] (Process for creating alignment holes) In this embodiment, a step of forming an alignment hole as appropriate for the purpose of alignment for exposure to form a wiring pattern may be included. In this case, it is preferable to further form holes around the alignment hole. The method of forming the alignment hole and the holes around the alignment hole can be a known drilling method used in the manufacture of ordinary printed wiring boards, for example, a drilling method and an X-ray or laser drilling method.

[0079] [Printed Wiring Board] According to this embodiment, by going through the above steps, a metal wiring having a predetermined thickness (D) and width (W) is formed from the first metal foil 11, and a metal wiring having a predetermined thickness (d) and width (w) is formed from the second metal foil 12 as necessary. Then, a metal foil-clad laminate 26 having a predetermined wiring pattern with metal wiring having a predetermined thickness (D) and width (W) and a predetermined gap (U) between the metal wirings, and a metal foil-clad laminate 26 having a predetermined wiring pattern with metal wiring having a predetermined thickness (d) and width (w) and a predetermined gap (u) between the metal wirings as necessary, and a printed wiring board having the metal foil-clad laminate 26 can be obtained. The metal foil-clad laminate 26 and the printed wiring board may each have via holes and / or through holes.

[0080] The printed wiring board of the present embodiment has uniform gaps between the metal wirings and fine wiring, and therefore has an insulating resin layer and metal wiring laminated on the insulating resin layer, the thickness (D) of the metal wiring is 3 to 20 μm, the gap (U) between the metal wirings is 12 to 50 μm, the width (W) of the metal wiring is 12 to 50 μm, the ratio (U / D) of the thickness (D) of the metal wiring to the gap (U) between the metal wirings is 1.0 or more, and the average thickness (D ave ) and the average gap between metal lines (U ave ) and the ratio (U ave / D ave ) is 1.60 to 1.80, the ratio (W / D) of the thickness (D) of the metal wiring to the width (W) of the metal wiring is 1.0 or more, and the average thickness (D ave ) and the average width of the metal wiring (W ave ) and the ratio (W ave / D ave ) is preferably 1.60 to 1.80. The printed wiring board has a predetermined wiring pattern with predetermined metal wiring and a predetermined gap between the metal wiring on the surface of the first metal foil 11, and may have a predetermined wiring pattern with predetermined metal wiring and a predetermined gap between the metal wiring on the surface of the second metal foil 12 as necessary. The printed wiring board can be used in various electronic components such as semiconductor devices.

[0081] For the insulating resin layer and the metal wiring, see the above.

[0082] The thicknesses (D) and (d) of the metal wiring are in the range of 3 to 20 μm, respectively, from the viewpoint of increasing the density of the metal wiring that transmits electric signals. layer The thickness (D) and (d) of the metal wiring are preferably uniform, and any thickness (D b ), and an arbitrary thickness (d b ) is more preferably the same as the thickness (D). The variation in thickness (D) is calculated using the average thickness, maximum thickness, and minimum thickness of the thickness (D), and it is preferable that the thickness (D) is in the range of 0 to 25% of the average thickness. Similarly, it is preferable that the thickness (d) is in the range of 0 to 25% of the average thickness. The material, thickness, and the method of measuring the variation of the metal wiring are described in the above-mentioned thickness (D). b ) and (d b ) and the Examples.

[0083] The gaps (U) and (u) between the metal wirings are each in the range of 12 to 50 μm from the viewpoint of increasing the density of the metal wiring that transmits electric signals. The gaps (U) and (u) between the metal wirings are the gaps between the metal wirings formed on the first metal foil 11 and the gaps between the metal wirings formed on the second metal foil 12, respectively. In this embodiment, the gaps (U) and (u) are the widths on the surface of the insulating resin layer, like the gaps (S) and (s) shown in FIG. 3.

[0084] From the viewpoint of increasing the density of metal wiring that transmits electric signals, the metal foil-clad laminate 26 and the printed wiring board preferably have two or more consecutive gaps (US) having the same width as the gaps (S) between the metal wirings among the gaps (U) formed in the first metal foil 11, more preferably have three or more consecutive gaps, and even more preferably have four or more consecutive gaps. The upper limit is, for example, 100. Similarly, in terms of increasing the density of metal wiring that transmits electric signals, the metal foil-clad laminate 26 and the printed wiring board preferably have two or more consecutive gaps (us) having the same width as the gaps (s) between the metal wirings among the gaps (u) formed in the second metal foil 12, more preferably three or more consecutive gaps, and even more preferably four or more consecutive gaps (us). The upper limit is, for example, 100.

[0085] The widths (W) and (w) of the metal wiring are each in the range of 12 to 50 μm from the viewpoint of increasing the density of the metal wiring that transmits electric signals. The widths (W) and (w) of the metal wiring refer to the width 44 of the metal wiring as shown in FIG. 3.

[0086] The ratio (U / D) of the thickness (D) of the metal wiring to the gap (U) between the metal wiring, and the ratio (u / d) of the thickness (d) of the metal wiring to the gap (u) between the metal wiring are each 1.0 or more, preferably 1.2 or more, because narrow portions in the gap between the metal wirings cause insulation failure at those portions. The upper limit is not particularly limited, but is, for example, 2.4 or less for each. The ratio (U / D) is calculated from the ratio between the maximum thickness calculated from the thickness variation in the thickness (D) of the metal wiring and the minimum gap in the gap (U) between the metal wirings. The ratio (u / d) is calculated in the same manner.

[0087] Average thickness of metal wiring (D ave ) and the average gap between metal lines (U ave ) and the ratio (U ave / D ave ), and the average thickness of the metal wiring (d ave ) and the average gap between metal lines (u ave ) and the ratio (u ave / d ave ) are 1.60 to 1.80, respectively. ave / D ave ) and ratio (u ave / d ave ) is within the above range, the resulting metal foil-clad laminate 26 and printed wiring board have uniform and fine gaps between the metal wirings and good metal wiring.

[0088] The ratio (W / D) of the thickness (D) of the metal wiring to the width (W) of the metal wiring, and the ratio (w / d) of the thickness (d) of the metal wiring to the width (w) of the metal wiring are each 1.0 or more, preferably 1.2 or more, because a narrow width of the metal wiring compared to the thickness of the metal wiring causes insulation failure. The upper limit is not particularly limited, but is, for example, 2.4 or less for each. The ratio (W / D) is calculated from the ratio between the maximum thickness of the metal wiring (D) calculated from the thickness variation and the minimum width of the width (W) between the metal wirings. The ratio (w / d) is calculated in the same manner.

[0089] Average thickness of metal wiring (D ave ) and the average width of the metal wiring (W ave ) and the ratio (W ave / D ave ), and the average thickness of the metal wiring (d ave ) and the average width of the metal wiring (w ave ) and the ratio (w ave / d ave ) are 1.60 to 1.80, respectively. ave / D ave ) and ratio (w ave / d ave ) is within the above range, the resulting metal foil-clad laminate 26 and printed wiring board have uniform gaps between the metal wirings, fine and good metal wiring.

[0090] Average thickness of metal wiring (D ave ) and (d ave ), the average gap between metal lines (U ave ) and (u ave ), and the average width of the metal wiring (W ave ) and (w ave ) are the average values ​​of the thicknesses (D) and (d) of the metal wiring, the gaps (U) and (u) between the metal wiring, and the widths (W) and (w) of the metal wiring in the resulting metal foil-clad laminate 26 and printed wiring board. Specific methods of measuring and calculating the values ​​and average values ​​of these thicknesses, gaps, and widths are described in the above-mentioned thickness (D b ) and (db ) and the Examples. In addition, in the obtained metal foil-clad laminate 26 and printed wiring board, the thicknesses (D) and (d) of the metal wiring, the gaps ( U ) and (u), width of metal wiring (W) and (w), ratio (U / D) and ratio (u / d), ratio (U ave / D ave ) and ratio (u ave / d ave ), ratio (W / D) and ratio (w / d), and ratio (W ave / D ave ) and ratio (w ave / d ave ) may be the same or different, but are preferably the same in order to reduce the occurrence of poor conduction of the metal wiring and poor insulation between the metal wirings. EXAMPLES

[0091] Examples of the present embodiment will be described with reference to FIG. 1, but the present embodiment is not limited to these examples.

[0092] [Evaluation method] (1) A method for evaluating the thickness of metal foil, thickness variation, gaps between resist patterns, gaps between metal wiring, length of metal wiring, and width of metal wiring in a metal foil-clad laminate before wiring formation The thickness (D b The thickness (D b The thickness variation was calculated using the maximum thickness, the minimum thickness and the average thickness in the metal foil-clad laminate before the wiring was formed. b ) was measured, and the thickness variation was calculated. In addition, the thickness (d b) were measured, and the average thickness and thickness variation were calculated. Similarly, the gaps (R) and (r) between the resist patterns, the gaps (S) and (s) between the metal wirings, the lengths (L) and (l) of the metal wirings, and the widths (W b ) and (w b ) was measured.

[0093] (2) In the metal foil-clad laminate after wiring formation, the thickness of the metal wiring, the gap between the metal wiring, the width of the metal wiring, the average thickness of the metal wiring, the average gap between the metal wiring, the average width of the metal wiring, the ratio (U / D), the ratio (W / D), and the ratio (U ave / D ave ), and ratio (W ave / D ave ) Evaluation method After the metal foil-clad laminate after the wiring was formed was subjected to cross-sectional polishing, the thickness (D) of the metal wiring formed on the first metal foil 11, the gap (U) between the metal wirings, and the width (W) of the metal wiring were measured by microscopic observation (magnification: 500 times). From these values, the average thickness (D ave ), the average gap between metal lines (U ave ), and the average width of the metal wiring (W ave ) was obtained. In addition, the maximum thickness, minimum thickness, and average thickness of the metal wiring (D ave From these values, the thickness variation was calculated. The ratio (U / D) of the thickness of the metal wiring (D) to the gap between the metal wiring (U), the ratio (W / D) of the thickness of the metal wiring (D) to the width of the metal wiring (W), and the average thickness of the metal wiring (D ave ) and the average gap between metal lines (U ave ) and the ratio (U ave / D ave ), and the average thickness of the metal wiring (D ave ) and the average width of the metal wiring (W ave ) and the ratio (W ave / D ave ) were calculated respectively. Similarly, the thickness (d), the gap (u) between the metal wirings, and the width (w) of the metal wirings formed on the second metal foil 12 were measured, and the average thickness (d ave ), the average gap between metal lines (u ave ), and the average width of the metal wiring (w ave The maximum thickness, minimum thickness, and average thickness of the metal wiring (d ave From these values, the thickness variation was calculated. From these values, the ratio (u / d) of the thickness of the metal wiring (d) to the gap between the metal wiring (u), the ratio (w / d) of the thickness of the metal wiring (d) to the width of the metal wiring (w), and the average thickness of the metal wiring (d ave ) and the average gap between metal lines (u ave ) and the ratio (u ave / d ave ), and the average thickness of the metal wiring (d ave ) and the average width of the metal wiring (w ave ) and the ratio (w ave / d ave ) were calculated respectively.

[0094] (3) Evaluation of gaps (U) and (u) between metal wiring Among the gaps (U) between the metal wirings obtained by the evaluation method (2) above, the gap farthest from the design value was used, and if the gap was within 30% of the gap (S) (design value), it was judged as good, and if it exceeded 30%, it was judged as bad. The gaps (u) between the metal wirings obtained by the evaluation method (2) above were also evaluated in the same manner. In addition, if the average value exceeds 30% of the design value, it is judged to be defective because there is an increased risk of shorting with adjacent wiring or of poor conductivity due to the thinning of the metal wiring.

[0095] (4) Evaluation of the gaps (US) between metal wiring and the continuity of (us) Among the gaps (U) between the metal wirings obtained by the evaluation method (2) above, the gaps (US) having the same width as the gaps (S) were counted to evaluate the continuity. The continuity was also evaluated in the same manner for the gaps (u) between the metal wirings obtained by the evaluation method (2) above.

[0096] Example 1 As shown in FIG. 1(a), a metal foil-clad laminate 21 was prepared in which a copper foil (first metal foil 11, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm), an insulating resin layer 10 (GHPL-830NX A-IT56 (trade name) manufactured by Mitsubishi Gas Chemical Co., Inc., thickness of the insulating resin layer 10: 100 μm), and a copper foil (second metal foil 12, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm) were laminated in this order. The first metal foil 11 and the second metal foil 12 were etched using a soft etching solution of peroxide-sulfuric acid (CPE-700 (trade name) manufactured by Mitsubishi Gas Chemical Co., Inc.) so that the surface of the first metal foil 11 and the surface of the second metal foil 12 each had a thickness in the range of 3 to 5 μm.

[0097] Next, the metal foil-clad laminate 21 was subjected to drilling of through-holes using a carbon dioxide (CO2) laser processing machine (GTW-4 (product name) manufactured by Mitsubishi Electric Corporation). After forming a plating layer of 0.3 to 0.5 μm in thickness by electroless plating on the metal foil-clad laminate having through-holes, a plating layer of 15 to 20 μm was applied by copper sulfate plating using copper sulfate (concentration: 60 to 80 g / L) and sulfuric acid (concentration: 150 to 200 g / L) to obtain a metal foil-clad laminate in which the first metal foil 11 and the second metal foil 12 are electrically connected. The first metal foil 11 and the second metal foil 12 in the metal foil-clad laminate were etched using a peroxide-sulfuric acid-based soft etching solution (CPE-700 (product name) manufactured by Mitsubishi Gas Chemical Company, Inc.) to a uniform thickness (D) of 15 μm on the surface of the first metal foil 11 and the surface of the second metal foil 12, respectively. b ) and (d b ) (thickness variation: 25%) to obtain a metal foil-clad laminate 22 as shown in FIG. 1(b).

[0098] Next, a router processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) was used to form alignment holes in the metal foil-clad laminate 22. Thereafter, a dry film resist (RD-2010 (product name) manufactured by Hitachi Chemical Co., Ltd.) was laminated on both sides of the metal foil-clad laminate 22 (on the surfaces of the first metal foil 11 and the second metal foil 12) at a temperature of 110±10° C. and a pressure of 0.50±0.02 MPa to form a first resist layer 13 (thickness: 10 μm) and a second resist layer 14 (thickness: 10 μm), and a metal foil-clad laminate 23 was obtained as shown in FIG. 1(c).

[0099] Next, using the alignment holes as a reference, the first resist layer 13 and the second resist layer 14 were exposed along the circuit pattern using a parallel exposure machine (IP3650HH (trade name) manufactured by ADTEC Engineering Co., Ltd.) so that the gaps (R) and (r) between the resist patterns were 22 μm, respectively, and masking was performed. Thereafter, using a spray device having a two-fluid nozzle (Hybrid Development Device (trade name) manufactured by Tokyo Kakoki Co., Ltd.), the dry film resist was developed by spraying air together with a 1% aqueous sodium carbonate solution (developer) at a spray pressure of 0.11 MPa and a spray time of 25 seconds, forming resist patterns on each of the first resist layer 13 and the second resist layer 14, and a metal foil-clad laminate 24 was obtained as shown in FIG. 1 (d). The obtained resist patterns were formed in parallel lines.

[0100] Next, in the metal foil-clad laminate 24, a spray device having a two-fluid nozzle (Hybrid Etching Device (product name) manufactured by Tokyo Kakoki Co., Ltd.) was used to perform etching so that the gaps (S) and (s) between the metal wirings of the first metal foil 11 and the second metal foil 12 were 25 μm (design value), and the first metal foil 11 had an arbitrary thickness (D b ) to the gap between metal wiring (S) (S / D b ) is 1.67 (design value), so it exceeds 1.6, and the arbitrary thickness (d b ) to the gap between metal wiring (s) (s / d b) is 1.67 (design value), which exceeds 1.6, the length (L) of the metal wiring in the first metal foil 11 is 1000 μm, the length (l) of the metal wiring in the second metal foil 12 is 1000 μm, and the width (W b ) and the gap between the metal wirings (S) are all the same ((W b )=(S)), and the width of the metal wiring (w b ) and the gap (s) between the metal wiring are all the same ((w b An etching solution of a cupric chloride aqueous solution (a mixture of a copper concentration of 120 to 180 g / L and a hydrochloric acid concentration of 100 to 150 g / L) was sprayed for 40 seconds at an etching rate of 0.7 μm / sec. with an etching solution flow rate of 2.0 L / min. and an air flow rate of 200 L / min. so that (s)=(s)), thereby etching the first metal foil 11 and the second metal foil 12 in the areas where the resist pattern was not formed, thereby obtaining a metal foil-clad laminate 25 having metal wiring on each of the first metal foil 11 and the second metal foil 12 (FIG. 1(e)).

[0101] Next, the first resist layer 13 and the second resist layer 14 were peeled off and removed using a 3% aqueous potassium hydroxide solution, to obtain a metal foil-clad laminate 26 (FIG. 1(f)).

[0102] When the obtained metal foil-clad laminate 26 was measured, the thickness (D) of the metal wiring on the surface of the first metal foil 11 was 15 μm (thickness variation: 25%), and the average thickness (D ave ) is 15 μm, the gap between the metal lines (U) is 25±5 μm, and the average gap between the metal lines (U ave ) is 25 μm, the width (W) of the metal wiring is 25±5 μm, and the average width (W ave ) is 25 μm, the ratio (U / D) of the thickness of the metal wiring (D) to the gap between the metal wirings (U) is 1.067 (=(25-5) μm / (15+15×25%) μm), and the average thickness of the metal wiring (D ave ) and the average gap between metal lines (U ave ) and the ratio (U ave / D ave) is 1.67, the ratio (W / D) of the thickness (D) of the metal wiring to the width (W) of the metal wiring is 1.067 (=(25-5)μm / (15+15×25%)μm), and the average thickness (D ave ) and the average width of the metal wiring (W ave ) and the ratio (W ave / D ave On the surface of the second metal foil 12, the thickness (d) of the metal wiring was 15 μm (thickness variation: 25%), and the average thickness (d ave ) is 15 μm, the gap between the metal lines (u) is 25±5 μm, and the average gap between the metal lines (u ave ) is 25 μm, the width (w) of the metal wiring is 25±5 μm, and the average width (w ave ) is 25 μm, the ratio (u / d) of the thickness (d) of the metal wiring to the gap (u) between the metal wiring is 1.067 (=(25-5) μm / (15+15×25%) μm), and the average thickness (d ave ) and the average gap between metal lines (u ave ) and the ratio (u ave / d ave ) is 1.67, the ratio (w / d) of the thickness (d) of the metal wiring to the width (w) of the metal wiring is 1.067 (=(25-5)μm / (15+15×25%)μm), and the average thickness (d ave ) and the average width of the metal wiring (w ave ) and the ratio (w ave / d ave ) was 1.67. In addition, the gap (U) between the metal wirings was 25±5 μm, and the gap (u) between the metal wirings was 25±5 μm, so that the average values ​​of the gaps (U) and (u) were within 30% of the design value (25 μm). Therefore, it was confirmed that the obtained metal foil-clad laminate 26 had good metal wiring. It was confirmed that, in the obtained metal foil-clad laminate 26, the gaps (U) between the metal wirings formed in the first metal foil 11 had four consecutive gaps (US) having the same width as the gap (S) (25 μm), and that the gaps (u) between the metal wirings formed in the second metal foil 12 had four consecutive gaps (us) having the same width as the gap (s) (25 μm). In the obtained metal foil-clad laminate, the minimum width of the metal wiring was 20 μm. Therefore, it was confirmed that the metal foil-clad laminate 26 has good metal wiring with uniform and fine gaps between the metal wirings.

[0103] Example 2 As shown in FIG. 1(a), a metal foil-clad laminate 21 was prepared in which a copper foil (first metal foil 11, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm), an insulating resin layer 10 (GHPL-830NX A-IT56 (trade name) manufactured by Mitsubishi Gas Chemical Co., Inc., thickness of the insulating resin layer 10: 100 μm), and a copper foil (second metal foil 12, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm) were laminated in this order. The first metal foil 11 and the second metal foil 12 were etched using a soft etching solution of peroxide-sulfuric acid (CPE-700 (trade name) manufactured by Mitsubishi Gas Chemical Co., Inc.) so that the surface of the first metal foil 11 and the surface of the second metal foil 12 each had a thickness in the range of 3 to 5 μm.

[0104] For the metal foil-clad laminate 21, a plating layer having a thickness of 0.3 to 0.5 μm was formed on each of the first metal foil 11 and the second metal foil 12 by electroless plating, and then a plating layer having a thickness of 15 to 20 μm was applied to each of the first metal foil 11 and the second metal foil 12 by copper sulfate plating using copper sulfate (concentration: 60 to 80 g / L) and sulfuric acid (concentration: 150 to 200 g / L), thereby obtaining a metal foil-clad laminate. For the first metal foil 11 and the second metal foil 12 in the metal foil-clad laminate, a soft etching solution based on peroxide and sulfuric acid (CPE-700 (product name) manufactured by Mitsubishi Gas Chemical Company, Inc.) was used to etch the surface of the first metal foil 11 and the surface of the second metal foil 12 to a uniform thickness (D) of 9 μm, respectively. b ) and (d b ) (thickness variation: 20% each) to obtain a metal foil-clad laminate 22 as shown in FIG. 1(b) (however, having no through-holes or via-holes).

[0105] Next, a router processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) was used to form alignment holes in the metal foil-clad laminate 22. Thereafter, a dry film resist (RD-2010 (product name) manufactured by Hitachi Chemical Co., Ltd.) was laminated on both sides of the metal foil-clad laminate 22 (on the surfaces of the first metal foil 11 and the second metal foil 12) at a temperature of 110±10° C. and a pressure of 0.50±0.02 MPa to form a first resist layer 13 (thickness: 10 μm) and a second resist layer 14 (thickness: 10 μm), and a metal foil-clad laminate 23 was obtained (however, it did not have through holes and via holes) as shown in FIG. 1(c).

[0106] Next, using the alignment holes as a reference, the first resist layer 13 and the second resist layer 14 were exposed along the circuit pattern using a parallel exposure machine (IP3650HH (trade name) manufactured by ADTEC Engineering Co., Ltd.) so that the gaps (R) and (r) between the resist patterns were 11 μm, respectively, and masking was performed. Thereafter, using a spray device having a two-fluid nozzle (Hybrid Development Device (trade name) manufactured by Tokyo Kakoki Co., Ltd.), the dry film resist was developed by spraying air together with a 1% aqueous sodium carbonate solution (developer) at a spray pressure of 0.11 MPa and a spray time of 25 seconds, forming resist patterns on each of the first resist layer 13 and the second resist layer 14, and a metal foil-clad laminate 24 was obtained as shown in FIG. 1(d) (however, it did not have through holes and via holes). The obtained resist patterns were formed in parallel lines.

[0107] Next, in the metal foil-clad laminate 24, a spray device having a two-fluid nozzle (Hybrid Etching Device (product name) manufactured by Tokyo Kakoki Co., Ltd.) was used to perform etching so that the gaps (S) and (s) between the metal wirings of the first metal foil 11 and the second metal foil 12 were 15 μm (design value), and the first metal foil 11 had an arbitrary thickness (D b ) to the gap between metal wiring (S) (S / D b ) is 1.67 (design value), so it exceeds 1.6, and the arbitrary thickness (d b ) to the gap between metal wiring (s) (s / db ) is 1.67 (design value), which exceeds 1.6, the length (L) of the metal wiring in the first metal foil 11 is 800 μm, the length (l) of the metal wiring in the second metal foil 12 is 800 μm, and the width (W b ) and the gap between the metal wirings (S) are all the same ((W b )=(S)), and the width of the metal wiring (w b ) and the gap (s) between the metal wiring are all the same ((w b An etching solution of a cupric chloride aqueous solution (a mixed solution of a copper concentration of 120 to 180 g / L and a hydrochloric acid concentration of 100 to 150 g / L) was sprayed for 26 seconds at an etching rate of 0.7 μm / sec. with an etching solution flow rate of 2.0 L / min. and an air flow rate of 200 L / min. so that (s)=(s)), thereby etching the first metal foil 11 and the second metal foil 12 in the portions on which the resist pattern was not formed, thereby obtaining a metal foil-clad laminate 25 having metal wiring on each of the first metal foil 11 and the second metal foil 12 (FIG. 1(e), but having no through-holes or via-holes).

[0108] Next, the first resist layer 13 and the second resist layer 14 were peeled off and removed using a 3% aqueous potassium hydroxide solution, to obtain a metal foil-clad laminate 26 (FIG. 1(f), but having no through-holes or via-holes).

[0109] When the obtained metal foil-clad laminate 26 was measured, the thickness (D) of the metal wiring on the surface of the first metal foil 11 was 9 μm (thickness variation: 20%), and the average thickness (D ave ) is 9 μm, the gap between the metal lines (U) is 15±3 μm, and the average gap between the metal lines (U ave ) is 15 μm, the width (W) of the metal wiring is 15±3 μm, and the average width (W ave ) is 15 μm, the ratio (U / D) of the thickness of the metal wiring (D) to the gap between the metal wirings (U) is 1.11, and the average thickness of the metal wiring (D ave ) and the average gap between metal lines (U ave ) and the ratio (U ave / D ave) is 1.67, the ratio (W / D) of the thickness (D) of the metal wiring to the width (W) of the metal wiring is 1.11, and the average thickness (D ave ) and the average width of the metal wiring (W ave ) and the ratio (W ave / D ave On the surface of the second metal foil 12, the thickness (d) of the metal wiring was 9 μm (thickness variation: 25%), and the average thickness (d ave ) is 9 μm, the gap between the metal lines (u) is 15±3 μm, and the average gap between the metal lines (u ave ) is 15 μm, the width (w) of the metal wiring is 15±3 μm, and the average width (w ave ) is 15 μm, the ratio (u / d) of the thickness (d) of the metal wiring to the gap (u) between the metal wiring is 1.11, and the average thickness (d ave ) and the average gap between metal lines (u ave ) and the ratio (u ave / d ave ) is 1.67, the ratio (w / d) of the thickness (d) of the metal wiring to the width (w) of the metal wiring is 1.11, and the average thickness (d ave ) and the average width of the metal wiring (w ave ) and the ratio (w ave / d ave ) was 1.67. In addition, the gap (U) between the metal wirings was 15±3 μm, and the gap (u) between the metal wirings was 15±3 μm, so that the average values ​​of the gaps (U) and (u) were within 30% of the design value (15 μm). Therefore, it was confirmed that the obtained metal foil-clad laminate 26 had good metal wiring. It was confirmed that, in the obtained metal foil-clad laminate 26, the gaps (U) between the metal wirings formed in the first metal foil 11 had four consecutive gaps (US) having the same width as the gap (S) (15 μm), and that the gaps (u) between the metal wirings formed in the second metal foil 12 had four consecutive gaps (us) having the same width as the gap (s) (15 μm). In the obtained metal foil-clad laminate, the minimum width of the metal wiring was 12 μm. Therefore, it was confirmed that the metal foil-clad laminate 26 has good metal wiring with uniform and fine gaps between the metal wirings.

[0110] Example 3 As shown in FIG. 1(a), a metal foil-clad laminate 21 was prepared in which a copper foil (first metal foil 11, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm), an insulating resin layer 10 (GHPL-830NX A-IT56 (product name) manufactured by Mitsubishi Gas Chemical Co., Inc., thickness of the insulating resin layer 10: 100 μm), and a copper foil (second metal foil 12, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm) were laminated in this order. The first metal foil 11 and the second metal foil 12 were etched to a uniform thickness (D) of 9 μm on the surface of the first metal foil 11 and the surface of the second metal foil 12, respectively, using a soft etching solution of a peroxide-sulfuric acid system (CPE-700 (product name) manufactured by Mitsubishi Gas Chemical Co., Inc.). b ) and (d b ) (thickness variation: 15% each) to obtain a metal foil-clad laminate 22 as shown in FIG. 1(b) (however, having no through-holes or via-holes).

[0111] Next, a router processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) was used to form alignment holes in the metal foil-clad laminate 22. Thereafter, a dry film resist (RD-2010 (product name) manufactured by Hitachi Chemical Co., Ltd.) was laminated on both sides of the metal foil-clad laminate 22 (on the surfaces of the first metal foil 11 and the second metal foil 12) at a temperature of 110±10° C. and a pressure of 0.50±0.02 MPa to form a first resist layer 13 (thickness: 10 μm) and a second resist layer 14 (thickness: 10 μm), and a metal foil-clad laminate 23 was obtained (however, it did not have through holes and via holes) as shown in FIG. 1(c).

[0112] Next, using the alignment holes as a reference, the first resist layer 13 and the second resist layer 14 were exposed along the circuit pattern using a parallel exposure machine (IP3650HH (trade name) manufactured by ADTEC Engineering Co., Ltd.) so that the gaps (R) and (r) between the resist patterns were 12 μm, respectively, and masking was performed. Thereafter, using a spray device having a two-fluid nozzle (Hybrid Development Device (trade name) manufactured by Tokyo Kakoki Co., Ltd.), the dry film resist was developed by spraying air together with a 1% aqueous sodium carbonate solution (developer) at a spray pressure of 0.11 MPa and a spray time of 25 seconds, forming resist patterns on each of the first resist layer 13 and the second resist layer 14, and a metal foil-clad laminate 24 was obtained as shown in FIG. 1(d) (however, it does not have through holes and via holes). The obtained resist patterns were formed in parallel lines.

[0113] Next, in the metal foil-clad laminate 24, a spray device having a two-fluid nozzle (Hybrid Etching Device (product name) manufactured by Tokyo Kakoki Co., Ltd.) was used to perform etching so that the gaps (S) and (s) between the metal wirings of the first metal foil 11 and the second metal foil 12 were 15 μm (design value), and the first metal foil 11 had an arbitrary thickness (D b ) to the gap between metal wiring (S) (S / D b ) is 1.67 (design value), so it exceeds 1.6, and the arbitrary thickness (d b ) to the gap between metal wiring (s) (s / d b ) is 1.67 (design value), which exceeds 1.6, the length (L) of the metal wiring in the first metal foil 11 is 500 μm, the length (l) of the metal wiring in the second metal foil 12 is 500 μm, and the width (W b ) and the gap between the metal wirings (S) are all the same ((W b )=(S)), and the width of the metal wiring (w b ) and the gap (s) between the metal wiring are all the same ((w bAn etching solution of a cupric chloride aqueous solution (a mixed solution of a copper concentration of 120 to 180 g / L and a hydrochloric acid concentration of 100 to 150 g / L) was sprayed for 22 seconds at an etching rate of 0.7 μm / sec. with an etching solution flow rate of 2.0 L / min. and an air flow rate of 200 L / min. so that (s)=(s)), thereby etching the first metal foil 11 and the second metal foil 12 in the portions on which the resist pattern was not formed, thereby obtaining a metal foil-clad laminate 25 having metal wiring on each of the first metal foil 11 and the second metal foil 12 (FIG. 1(e), but having no through-holes or via-holes).

[0114] Next, the first resist layer 13 and the second resist layer 14 were peeled off and removed using a 3% aqueous potassium hydroxide solution, to obtain a metal foil-clad laminate 26 (FIG. 1(f), but having no through-holes or via-holes).

[0115] When the obtained metal foil-clad laminate 26 was measured, the thickness (D) of the metal wiring on the surface of the first metal foil 11 was 9 μm (thickness variation: 15%), and the average thickness (D ave ) is 9 μm, the gap between the metal lines (U) is 15±1.5 μm, and the average gap between the metal lines (U ave ) is 15 μm, the width (W) of the metal wiring is 15±1.5 μm, and the average width (W ave ) is 15 μm, the ratio (U / D) of the thickness of the metal wiring (D) to the gap between the metal wirings (U) is 1.30, and the average thickness of the metal wiring (D ave ) and the average gap between metal lines (U ave ) and the ratio (U ave / D ave ) is 1.67, the ratio (W / D) of the thickness (D) of the metal wiring to the width (W) of the metal wiring is 1.30, and the average thickness (D ave ) and the average width of the metal wiring (W ave ) and the ratio (W ave / D ave On the surface of the second metal foil 12, the thickness (d) of the metal wiring was 9 μm (thickness variation: 15%), and the average thickness (d ave) is 9 μm, the gap between the metal lines (u) is 15±1.5 μm, and the average gap between the metal lines (d ave ) is 15 μm, the width (w) of the metal wiring is 15±1.5 μm, and the average width (w ave ) is 15 μm, the ratio (u / d) of the thickness (d) of the metal wiring to the gap (u) between the metal wiring is 1.30, and the average thickness (d ave ) and the average gap between metal lines (u ave ) and the ratio (u ave / d ave ) is 1.67, the ratio (w / d) of the thickness (d) of the metal wiring to the width (w) of the metal wiring is 1.30, and the average thickness (d ave ) and the average width of the metal wiring (w ave ) and the ratio (w ave / d ave ) was 1.67. In addition, the gap (U) between the metal wirings was 15±1.5 μm, and the gap (u) between the metal wirings was 15±1.5 μm, so that the average values ​​of the gaps (U) and (u) were within 30% of the design value (15 μm). Therefore, it was confirmed that the obtained metal foil-clad laminate 26 had good metal wiring. It was confirmed that, in the obtained metal foil-clad laminate 26, the gaps (U) between the metal wirings formed in the first metal foil 11 had two consecutive gaps (US) having the same width as the gap (S) (15 μm), and that the gaps (u) between the metal wirings formed in the second metal foil 12 had two consecutive gaps (us) having the same width as the gap (s) (15 μm). In the obtained metal foil-clad laminate, the minimum width of the metal wiring was 13 μm. Therefore, it was confirmed that the metal foil-clad laminate 26 has good metal wiring with uniform and fine gaps between the metal wirings.

[0116] Comparative Example 1 A metal foil-clad laminate 21 was prepared in which a copper foil (first metal foil 11, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm), an insulating resin layer 10 (GHPL-830NX A-IT56 (trade name) manufactured by Mitsubishi Gas Chemical Co., Inc., thickness of the insulating resin layer 10: 100 μm), and a copper foil (second metal foil 12, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm) were laminated in this order. The first metal foil 11 and the second metal foil 12 were etched using a peroxide-sulfuric acid-based soft etching solution (CPE-700 (trade name) manufactured by Mitsubishi Gas Chemical Co., Inc.) so that the surface of the first metal foil 11 and the surface of the second metal foil 12 each had a thickness in the range of 3 to 5 μm.

[0117] Next, the metal foil-clad laminate 21 was subjected to drilling of through-holes using a carbon dioxide (CO2) laser processing machine (GTW-4 (product name) manufactured by Mitsubishi Electric Corporation). After forming a plating layer of 0.3 to 0.5 μm in thickness by electroless plating on the metal foil-clad laminate having the through-holes, a plating layer of 15 to 20 μm was applied by copper sulfate plating using copper sulfate (concentration: 60 to 80 g / L) and sulfuric acid (concentration: 150 to 200 g / L) to obtain a metal foil-clad laminate in which the first metal foil 11 and the second metal foil 12 are electrically connected. The first metal foil 11 and the second metal foil 12 in the metal foil-clad laminate were etched using a peroxide-sulfuric acid-based soft etching solution (CPE-700 (product name) manufactured by Mitsubishi Gas Chemical Company, Inc.) to obtain a uniform thickness (D) of 18 μm on the surface of the first metal foil 11 and the surface of the second metal foil 12, respectively. b ) and (d b ) (thickness variation: 25%) to obtain a metal foil-clad laminate 22.

[0118] Next, a router processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) was used to form alignment holes in the metal foil-clad laminate 22. Thereafter, a dry film resist (RD-2010 (product name) manufactured by Hitachi Chemical Co., Ltd.) was laminated on both sides of the metal foil-clad laminate 22 (on the surfaces of the first metal foil 11 and the second metal foil 12) at a temperature of 110±10° C. and a pressure of 0.50±0.02 MPa to form a first resist layer 13 (thickness: 10 μm) and a second resist layer 14 (thickness: 10 μm), thereby obtaining a metal foil-clad laminate 23.

[0119] Next, using the alignment holes as a reference, the first resist layer 13 and the second resist layer 14 were exposed along the circuit pattern using a parallel exposure machine (IP3650HH (trade name) manufactured by ADTEC Engineering Co., Ltd.) so that the gaps (R) and (r) between the resist patterns were 22 μm, respectively, and masking was performed. Thereafter, using a spray device having a two-fluid nozzle (Hybrid Development Device (trade name) manufactured by Tokyo Kakoki Co., Ltd.), the dry film resist was developed by spraying air together with a 1% aqueous sodium carbonate solution (developer) at a spray pressure of 0.11 MPa for a spray time of 25 seconds, thereby obtaining a metal foil-clad laminate 24 in which a resist pattern was formed on each of the first resist layer 13 and the second resist layer 14. The obtained resist patterns were formed in parallel lines.

[0120] Next, in the metal foil-clad laminate 24, a spray device having a two-fluid nozzle (Hybrid Etching Device (product name) manufactured by Tokyo Kakoki Co., Ltd.) was used to perform etching so that the gaps (S) and (s) between the metal wirings of the first metal foil 11 and the second metal foil 12 were 25 μm (design value), and the first metal foil 11 had an arbitrary thickness (D b ) to the gap between metal wiring (S) (S / D b ) is 1.39 (design value), so it is 1.6 or less, and the arbitrary thickness (d b ) to the gap between metal wiring (s) (s / d b) is 1.39 (design value), which is 1.6 or less, the length (L) of the metal wiring in the first metal foil 11 is 1000 μm, the length (l) of the metal wiring in the second metal foil 12 is 1000 μm, and the width (W b ) and the gap between the metal wirings (S) are all the same ((W b )=(S)), and the width of the metal wiring (w b ) and the gap (s) between the metal wiring are all the same ((w b An etching solution of a cupric chloride aqueous solution (a mixed solution of a copper concentration of 120 to 180 g / L and a hydrochloric acid concentration of 100 to 150 g / L) was sprayed for 40 seconds at an etching rate of 0.7 μm / sec. with an etching solution flow rate of 2.0 L / min. and an air flow rate of 200 L / min. so that (s)=(s)), and the first metal foil 11 and the second metal foil 12 in the portions on which the resist pattern was not formed were etched, respectively.

[0121] Next, the first resist layer 13 and the second resist layer 14 were peeled off and removed using a 3% aqueous potassium hydroxide solution, and a metal foil-clad laminate A was obtained.

[0122] In the obtained metal foil-clad laminate A, the metal parts of the metal wiring in both the first metal foil 11 and the second metal foil 12 were etched in a fan-like shape from the surface of the metal foil toward the insulating resin layer, causing so-called "sagging," making it difficult to form fine wiring with uniform gaps between the metal wiring. In addition, the occurrence of "sagging" caused the wiring to short-circuit near the insulating resin layer.

[0123] Comparative Example 2 In Comparative Example 1, the wiring was short-circuited near the insulating resin layer, so the etching time using the copper(II) chloride aqueous solution and air was increased. That is, under the condition that the flow rate of the etching solution was 2.0 L / min. and the flow rate of the air was 200 L / min., the etching rate was 0.7 μm / sec., and the etching solution of the copper(II) chloride aqueous solution (a mixed solution of copper concentration of 120 to 180 g / L and hydrochloric acid concentration of 100 to 150 g / L) was sprayed for 50 seconds, and the first metal foil 11 and the second metal foil 12 in the part where the resist pattern was not formed were etched, respectively. Next, the first resist layer 13 and the second resist layer 14 were peeled off and removed using a 3% potassium hydroxide aqueous solution, and a metal foil-clad laminate B was obtained.

[0124] When the obtained metal foil-clad laminate B was measured, the thickness (D) of the metal wiring on the surface of the first metal foil 11 was 18 μm (thickness variation: 25%), and the average thickness (D ave ) is 18 μm, the gap between the metal lines (U) is 27±6 μm, and the average gap between the metal lines (U ave ) is 27 μm, the width (W) of the metal wiring is 23±6 μm, and the average width (W ave ) is 23 μm, the ratio (U / D) of the thickness of the metal wiring (D) to the gap between the metal wirings (U) is 0.93, and the average thickness of the metal wiring (D ave ) and the average gap between metal lines (U ave ) and the ratio (U ave / D ave ) is 1.50, the ratio (W / D) of the thickness (D) of the metal wiring to the width (W) of the metal wiring is 0.76, and the average thickness (D ave ) and the average width of the metal wiring (W ave ) and the ratio (W ave / D ave On the surface of the second metal foil 12, the thickness (d) of the metal wiring was 18 μm (thickness variation: 25%), and the average thickness (d ave ) is 18 μm, the gap between the metal lines (u) is 27±6 μm, and the average gap between the metal lines (u ave ) is 27 μm, the width (w) of the metal wiring is 23±6 μm, and the average width (w ave) is 23 μm, the ratio (u / d) of the thickness (d) of the metal wiring to the gap (u) between the metal wiring is 0.93, and the average thickness (d ave ) and the average gap between metal lines (u ave ) and the ratio (u ave / d ave ) is 1.50, the ratio (w / d) of the thickness (d) of the metal wiring to the width (w) of the metal wiring is 0.76, and the average thickness (d ave ) and the average width of the metal wiring (w ave ) and the ratio (w ave / d ave ) was 1.28. In addition, the gap (U) between the metal wirings was 27±6 μm, and the gap (u) between the metal wirings was 27±6 μm, so that the average values ​​of both the gaps (U) and (u) were 32% of the design value (25 μm). Therefore, the gaps between the metal wirings were defective.

[0125] In addition, the minimum width of the metal wiring in the obtained metal foil-clad laminate was 17 μm. As the wiring width became narrower, the transmission loss of the electrical signal increased, and the risk of disconnection also increased.

[0126] Comparative Example 3 A metal foil-clad laminate 21 was prepared in which a copper foil (first metal foil 11, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm), an insulating resin layer 10 (GHPL-830NX A-IT56 (trade name) manufactured by Mitsubishi Gas Chemical Co., Inc., thickness of the insulating resin layer 10: 100 μm), and a copper foil (second metal foil 12, 3EC-M2S-VLP manufactured by Mitsui Mining & Smelting Co., Ltd., thickness: 12 μm) were laminated in this order. The first metal foil 11 and the second metal foil 12 were etched using a peroxide-sulfuric acid-based soft etching solution (CPE-700 (trade name) manufactured by Mitsubishi Gas Chemical Co., Inc.) so that the surface of the first metal foil 11 and the surface of the second metal foil 12 each had a thickness in the range of 3 to 5 μm.

[0127] For the metal foil-clad laminate 21, a plating layer having a thickness of 0.3 to 0.5 μm was formed on each of the first metal foil 11 and the second metal foil 12 by electroless plating, and then a plating layer having a thickness of 15 to 20 μm was applied to each of the first metal foil 11 and the second metal foil 12 by copper sulfate plating using copper sulfate (concentration: 60 to 80 g / L) and sulfuric acid (concentration: 150 to 200 g / L), thereby obtaining a metal foil-clad laminate. For the first metal foil 11 and the second metal foil 12 in the metal foil-clad laminate, a soft etching solution based on peroxide and sulfuric acid (CPE-700 (product name) manufactured by Mitsubishi Gas Chemical Company, Inc.) was used to etch the surface of the first metal foil 11 and the surface of the second metal foil 12 to a uniform thickness (D) of 11 μm, respectively. b ) and (d b ) (thickness variation: 20% each) to obtain a metal foil-clad laminate 22 (however, having no through-holes or via-holes).

[0128] Next, a router processing machine (manufactured by Hitachi Via Mechanics Co., Ltd.) was used to form alignment holes in the metal foil-clad laminate 22. Thereafter, a dry film resist (RD-2010 (product name) manufactured by Hitachi Chemical Co., Ltd.) was laminated on both sides of the metal foil-clad laminate 22 (on the surfaces of the first metal foil 11 and the second metal foil 12) at a temperature of 110±10° C. and a pressure of 0.50±0.02 MPa to form a first resist layer 13 (thickness: 10 μm) and a second resist layer 14 (thickness: 10 μm), thereby obtaining a metal foil-clad laminate 23 (however, having no through-holes or via-holes).

[0129] Next, using the alignment holes as a reference, the first resist layer 13 and the second resist layer 14 were exposed along the circuit pattern using a parallel exposure machine (IP-3650HH (product name) manufactured by ADTEC Engineering Co., Ltd.) so that the gaps (R) and (r) between the resist patterns were 11 μm, respectively, and masking was performed. Thereafter, using a spray device having a two-fluid nozzle (Hybrid Development Device (product name) manufactured by Tokyo Kakoki Co., Ltd.), the dry film resist was developed by spraying air together with a 1% aqueous sodium carbonate solution (developer) at a spray pressure of 0.11 MPa for a spray time of 25 seconds, thereby obtaining a metal foil-clad laminate 24 in which a resist pattern was formed on each of the first resist layer 13 and the second resist layer 14 (however, it did not have a through hole or a via hole). The obtained resist pattern was formed in parallel lines.

[0130] Next, in the metal foil-clad laminate 24, a spray device having a two-fluid nozzle (Hybrid Etching Device (product name) manufactured by Tokyo Kakoki Co., Ltd.) was used to perform etching so that the gaps (S) and (s) between the metal wirings of the first metal foil 11 and the second metal foil 12 were 15 μm (design value), and the first metal foil 11 had an arbitrary thickness (D b ) to the gap between metal wiring (S) (S / D b ) is 1.36 (design value), so it is 1.6 or less, and the arbitrary thickness (d b ) to the gap between metal wiring (s) (s / d b ) is 1.36 (design value), which is 1.6 or less, the length (L) of the metal wiring in the first metal foil 11 is 1000 μm, the length (l) of the metal wiring in the second metal foil 12 is 1000 μm, and the width (W b ) and the gap between the metal wirings (S) are all the same ((W b )=(S)), and the width of the metal wiring (w b ) and the gap (s) between the metal wiring are all the same ((w bAn etching solution of a copper(II) chloride aqueous solution (a mixed solution of a copper concentration of 120 to 180 g / L and a hydrochloric acid concentration of 100 to 150 g / L) was sprayed for 26 seconds at an etching rate of 0.7 μm / sec. under an etching solution flow rate of 2.0 L / min. and an air flow rate of 200 L / min. so that (s)=(s)), and the first metal foil 11 and the second metal foil 12 in the portions where the resist pattern was not formed were etched, respectively. Next, the first resist layer 13 and the second resist layer 14 were peeled off and removed using a 3% potassium hydroxide aqueous solution, to obtain a metal foil-clad laminate C.

[0131] In the obtained metal foil-clad laminate C, the metal parts of the metal wiring in both the first metal foil 11 and the second metal foil 12 were etched in a fan-like shape from the surface of the metal foil toward the insulating resin layer, causing so-called "sagging," making it difficult to form fine wiring with uniform gaps between the metal wiring. In addition, the occurrence of "sagging" caused the wiring to short-circuit near the insulating resin layer.

[0132] Comparative Example 4 In Comparative Example 2, the wiring was short-circuited near the insulating resin layer, so the etching time using the copper(II) chloride aqueous solution and air was increased. That is, under the condition that the flow rate of the etching solution was 2.0 L / min. and the flow rate of the air was 200 L / min., the etching rate was 0.7 μm / sec., and the etching solution of the copper(II) chloride aqueous solution (a mixed solution of copper concentration of 120 to 180 g / L and hydrochloric acid concentration of 100 to 150 g / L) was sprayed for 36 seconds, and the first metal foil 11 and the second metal foil 12 in the part where the resist pattern was not formed were etched, respectively. Next, the first resist layer 13 and the second resist layer 14 were peeled off and removed using a 3% potassium hydroxide aqueous solution, and a metal foil-clad laminate D was obtained.

[0133] When the obtained metal foil-clad laminate D was measured, the thickness (D) of the metal wiring on the surface of the first metal foil 11 was 11 μm (thickness variation: 20%), and the average thickness (D ave ) is 11 μm, the gap between the metal lines (U) is 20±3 μm, and the average gap between the metal lines (U ave) is 20 μm, the width (W) of the metal wiring is 10±3 μm, and the average width (W ave ) is 10 μm, the ratio (U / D) of the thickness of the metal wiring (D) to the gap between the metal wirings (U) is 1.28, and the average thickness of the metal wiring (D ave ) and the average gap between metal lines (U ave ) and the ratio (U ave / D ave ) is 1.81, the ratio (W / D) of the thickness (D) of the metal wiring to the width (W) of the metal wiring is 0.53, and the average thickness (D ave ) and the average width of the metal wiring (W ave ) and the ratio (W ave / D ave On the surface of the second metal foil 12, the thickness (d) of the metal wiring was 11 μm (thickness variation: 20%), and the average thickness (d ave ) is 11 μm, the gap between the metal lines (u) is 20±3 μm, and the average gap between the metal lines (u ave ) is 20 μm, the width (w) of the metal wiring is 10±3 μm, and the average width (w ave ) is 10 μm, the ratio (u / d) of the thickness (d) of the metal wiring to the gap (u) between the metal wiring is 1.28, and the average thickness (d ave ) and the average gap between metal lines (u ave ) and the ratio (u ave / d ave ) is 1.81, the ratio (w / d) of the thickness (d) of the metal wiring to the width (w) of the metal wiring is 0.53, and the average thickness (d ave ) and the average width of the metal wiring (w ave ) and the ratio (w ave / d ave ) was 0.91. In addition, the gap (U) between the metal wirings was 20±3 μm, and the gap (u) between the metal wirings was 20±3 μm, so that the average values ​​of both the gaps (U) and (u) were 53% of the design value (15 μm). Therefore, the gaps between the metal wirings were defective.

[0134] In addition, the minimum width of the metal wiring in the obtained metal foil-clad laminate was 9 μm. As the wiring width became narrower, the transmission loss of the electrical signal increased, and the risk of disconnection also increased.

[0135] This application is based on a Japanese patent application (Patent Application No. 2019-88770) filed on May 9, 2019, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0136] According to the present invention, a printed wiring board having fine wiring with uniform gaps between metal wirings can be manufactured with high productivity. Also, according to the present invention, a printed wiring board having fine wiring with uniform gaps between metal wirings can be provided. [Explanation of symbols]

[0137] 10...insulating resin layer, 11...first metal foil, 12...second metal foil, 13...first resist layer, 14...second resist layer, 21...metal foil-clad laminate, 22...metal foil-clad laminate having been drilled and plated, 23...metal foil-clad laminate having first resist layer and second resist layer formed thereon, 24...metal foil-clad laminate having resist pattern formed thereon, 25...metal foil-clad laminate having metal wiring formed thereon, 26...metal foil-clad laminate having first resist layer and second resist layer removed therefrom, 31...spray for spraying developer, 32...spray for spraying etching solution, 41...gap between resist patterns (R), 42...gap between metal wiring (S), 43...arbitrary thickness (D) of metal foil b and D), 44…Width of metal wiring (W b and W)

Claims

1. Any thickness (D ｂ preparing a metal foil-clad laminate in which a metal foil having the above-mentioned composition and an insulating resin layer are laminated; forming a resist layer on the surface of the metal foil; a step of exposing and developing the resist layer to form a resist pattern; a step of spraying air together with an etching solution using a sprayer having a two-fluid nozzle to etch the metal foil in the portion where the resist pattern is not formed, thereby forming a metal wiring; removing the resist layer; In the step of forming the metal wiring, the spray is performed at an etching rate of 0.05 to 1.5 μm / sec. and a spraying time of 20 to 120 seconds, the flow rate of the etching solution in the two-fluid nozzle is 0.5 to 3.5 L / min., the flow rate of the air is 100 to 400 L / min., the gap (S) between the metal wirings is 15 to 50 μm, and the thickness (D) of the metal foil is 10 to 120 μm. ｂ The ratio of the gap (S) between the metal wirings (S / D ｂ The method for producing a printed wiring board, comprising forming the metal wiring so that the surface roughness (Tc) of the metal wiring exceeds 1.

6.

2. 2. The method for producing a printed wiring board according to claim 1, wherein the etching solution is an aqueous cupric chloride solution which is a mixture of a copper concentration of 120 to 180 g / L and a hydrochloric acid concentration of 100 to 150 g / L.

3. 3. The method for manufacturing a printed wiring board according to claim 1, wherein in the step of forming the resist pattern, a gap (R) between the resist patterns is formed to be 1 to 5 μm narrower than a gap (S) between the metal wirings.

4. The method for manufacturing a printed wiring board according to any one of claims 1 to 3, wherein the printed wiring board has two or more consecutive gaps (US) having the same width as the gaps (S) between the metal wirings among the gaps (U) formed in the metal foil.

5. In the step of forming the metal wiring, the width (W ｂ ) and the gap (S) between the metal wirings are the same ((W ｂ 5. The method for producing a printed wiring board according to claim 1, wherein the first and second electrodes are formed so that (a)=(S)).

6. In the step of preparing the metal foil-clad laminate, the metal foil is formed to any thickness (D ｂ The method for producing a printed wiring board according to any one of claims 1 to 5, wherein the thickness of the metal foil is adjusted so that the thickness of the metal foil is 100 μm or less.

7. The method for producing a printed wiring board according to any one of claims 1 to 6, wherein the resist layer formed on the surface of the metal foil has a thickness of 15 µm or less.

8. 8. The method for manufacturing a printed wiring board according to claim 1, wherein in the step of forming the metal wiring, the metal wiring is formed so that the length (L) of the metal wiring is 100 μm or more.

9. The method for producing a printed wiring board according to any one of claims 1 to 8, wherein the metal foil is a copper foil.

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