Dry film resist and printed circuit board producing method

A printed circuit board producing method in which a dry film resist is used, said dry film resist including:

• a support;
• first and second photo resist layers, disposed on said support, developable in alkaline development, and sensitive to active energy rays;
• said first photo resist layer being overlaid on said support;
• said second photo resist layer being overlaid on said first photo resist by application in a state of water dispersion emulsion;
• and
• a protective film overlaid on said second photo resist layer in a peelable manner;
• said printed circuit board producing method comprising steps of:
• supplying a laminate plate including an insulation substrate, plural through holes formed in said insulation substrate, and a copper plating layer overlaid on said insulation substrate;
• peeling said protective film from said dry film resist;
• laminating and heating said dry film resist and said laminate plate by opposing said second photo resist layer of said dry film resist to said laminate plate;
• applying said active energy rays to said dry film resist according to pattern information, said pattern information being associated with a portion for being covered among said through holes and a portion for forming a circuit pattern among said through holes, so as to expose a first portion in said first and second photo resist layers, said first portion being hardened and becoming insoluble to alkali;
• eliminating a portion of said first and second photo resist layers different from said first portion from said laminate plate by dissolution in aqueous solution of weak alkali;
• eliminating said copper plating layer from a periphery of said first portion in said insulation substrate by etching;
• and
• eliminating said first portion from said insulation substrate by dissolution in aqueous solution of strong alkali, to obtain a covered portion and said circuit pattern of said copper plating layer among said through holes.