Producing method of flexible wired circuit board

Abstract

A producing method of a flexible wired circuit board that can prevent the formation of a gap between an elongate substrate and a stiffener sheet bonded thereto to prevent contamination of the flexible wired circuit board obtained. In the process subsequent to the process of forming a conductive patternon a surface of the elongate substrateby the semi-additive process using electrolysis plating and then annealing the elongate substratewith the conductive patternin its wound up state, a stiffener sheethaving a width narrower than the elongate substrateis bonded to the back side of the elongate substrateThereafter, an oxidized film formed on a surface of the conductive patternis removed and then a solder resistis formed thereon. This prevents the strip of the stiffener sheetfrom the elongate substrateand in turn prevents etching solution or developing solution from entraining in a gap therebetween.