MULTILAYER PRINTED WIRING BOARD FOR SURFACE MOUNTING

摘要

PURPOSE:To elevate the reliability of a solder connection part by preventing the solder connection part of a composite type of multilayer printed wiring board surface mounted from cracking. CONSTITUTION:In an object wherein the insulating layer a of an outer layer circuit is made glass woven fabric impregnated with epoxy resin and an insulating layer b, which constitutes an inner layer circuit board, and an adhesive layer between the inner layer circuit board and the insulating layer are made glass unwoven fabric impregnated with epoxy resin, a layer of butyral denatured phenol resin is made in contact with the outer layer circuit inside of this. This layer becomes the shape of rubber at high temperature, and it prevents the solder connection part from cracking caused by stress by absorbing said stress based on the difference of thermal expansion coefficient between the parts mounted on the surface and the insulating layer.