Patent ID: 6884570

Claim:
A method of forming resist pattern film which comprises the following successive steps: (1) applying a positive actinic ray decomposing and developing dry film having on the surface of a nonactinic ray decomposing and developing substrate, a solid positive actinic ray decomposing and developing urethane resin layer formed by coating and heat-crosslinking a resin composition onto a surface of a coating substrate consisting of a through-hole plated, both side copper-cladded laminate so that the surface of the coating substrate may face to the urethane resin layer of the positive actinic ray decomposing and developing dry film, said resin composition being (1) a resin composition containing, as essential components, (A 1 ) at least one unsaturated compound selected from the group consisting of a vinyl ether group-containing compound, vinyl ester group containing compound and propenyl ester group-containing compound, (B 1 ) an acid group-containing urethane resin having a weight average molecular weight of 1,000 to 200,000 and an acid group content in the range of 0.5 to 10 equivalents per one kg of the resin, and (C) a photo-acid generator; (2) a resin composition containing, as essential components, (A 2 ) at least one unsaturated urethane based compound selected from the group consisting of a vinyl ether urethane based compound, vinyl ester urethane based compound and propenyl ester urethane based compound and propenyl ester urethane based compound, (B 2 ) at least one resin selected from the group consisting of (a) a carboxyl group and hydroxyphenyl group-containing polymer, (b) a carboxyl group-containing polymer and (c) a hydroxyphenyl group-containing polymer, and (C) a photo-acid generator, or (3) a resin composition containing, as essential components, (A 2 ) at least one unsaturated urethane based compound selected from the group consisting of a vinyl ether urethane based compound, (B 1 ) an acid group-containing urethane resin having a weight average molecular weight of 1,000 to 200,000 and an acid group content in the range of 0.5 to 10 equivalents per one kg of the resin, and (C) a photo-acid generator, (2) optionally stripping the non-actinic ray decomposing and developing substrate of the dry film, (3) irradiating an actinic ray through a mask or directly onto the surface of the dry film so as to obtain an intended pattern, optionally followed by heat treating, (4) stripping the non-actinic ray decomposing and developing substrate not stripped in the above step (2), (5) subjecting the positive actinic ray decomposing and developing urethane resin layer to a developing treatment, and (6) removing an irradiating area of the urethane resin layer to form a resist pattern film, either step (1) or (2) including a step of heat treating, and (7) etching the exposed copper cladded laminate.