METHOD FOR PRODUCTION OF PROTECTIVE RELIEFS Russian patent published in 1995 - IPC

FIELD: production of printed circuit boards. SUBSTANCE: method for production of protective reliefs includes application of dry-film photoresist to surface of copper foil, exposure to ultra-violet radiation through phototemplate, separation of polyethylene terephthalate base of film photoresist and development of photosensitive layer with the help of methyl chloroform with subsequent holding in darkness in the presence of atmospheric oxygen for 1-24 h at 10-40 C. Dry-film photoresist is used in form of the following composition, mas.p.: dimethacrylate-bis-(ethylene glycol)phthalate 40-60; I-chloro-2-hydroxy-3-methacryloyloxy propane 12-25; oligomethacrylate- bis-(oligooxypropyleneglycerol)phthalate (formula I) 5-10; polymethyl methacrylate (formula II) 90-110; benzophenone 3.5-6; 4,4'-bis- (dimethylamino)benzophenone 0.5-2.5; methyl violet dye C.J. No.42535 0.05-0.2; phthalic acid 0.05-0.4; triethyleneglycol diacetate (formula III) 10-15. Formulas I, II and III are given in invention description. EFFECT: higher resolving power of protective relief (from 75 to 90 mcm), reduced number of defects per meter of conductor length (by 4.57 times); increased yield of ready products (by 2.3 times); decreased width of separation zone at load of 6 kgf by 92.3%. 4 tbl