| 摘要 |
PROBLEM TO BE SOLVED: To make feasible of high quality mounting having thin and smoothed surface in less dispersion in thickness by successively laminating a specific optic-thermosetting undercoat layer, a specific interlayer insulating adhesive layer and copper foil on both surfaces of internal layer circuit board made of flame retardant epoxy resin impregnated glass cloth substrate. SOLUTION: An undercoating agent for an undercoating layer 3 is made from the following components for filling up the copper foil circuit gap of an internal layer circuit board 1 for smoothing the surface of an internal layer circuit 2. That is, novolak type epoxy resin in brominating percentage exceeding 20% and molecular weight of 500-4000, bisphenol type epoxy resin in molecular weight of 500-2000, bisphenol type epoxy resin in molecular weight not exceeding 500, glycylglycine acrylate, etc., hydroxy ehtyl acrylate, etc.; optical polymerization initiator; imidazole compound in melting point exceeding 130 deg.C and low temperature setting type imidazole compound. As for the interlayer insulating adhesive layer 4, epoxy resin, etc., in the mean molecular weight exceeding 10000 is applicable. |
