METHOD FOR PREPARING SUBSTRATE FOR FLEXIBLE PRINT WIRING BOARD AND SUBSTRATE FOR FLEXIBLE PRINT WIRING BOARD

摘要

A method for preparing a substrate for a flexible print wiring board having a polyimide based resin layer wherein a solution of a polyimide based resin precursor is directly applied on an electrically conducting material to form a polyimide based resin precursor layer and then the precursor layer is cured by heating to prepare a polyimide based resin layer, characterized in that a solution of a polyimide based resin precursor B, which is one of solutions of two types of polyimide based resin precursors, is directly applied on an electrically conducting material and then, on the resultant layer is applied a solution of a polyimide based resin precursor A which allows resolving the residual strain generated in the polyimide based resin formed by the curing of the above polyimide based resin precursor B.