PRODUCTION OF MULTILAYER WIRING BOARD

摘要

PURPOSE:To obtain a highly reliable multilayer wiring board easily at low cost by subjecting a polyimide precursor to heat treatment within a specific temperature range thereby permitting lap coating and thick film formation. CONSTITUTION:A board is coated with polyimide precursor and prebaked to form a lower layer polyimide precursor film. A predetermined pattern is then formed on the lower layer film and heat treated at 120-300 deg.C while furthermore the lower layer film is coated with polyimide precursor and prebaked thus forming an upper layer polyimide precursor. A pattern having common openings is then formed on the upper layer film and the entire film is subjected to firing. This method allows formation of a good thick film polyimide thus allowing production of highly reliable multilayer wiring board easily at low cost.