Patent ID: 6197425
Filing Date: 2001-03-06
Classification: H05K,Y10S,Y10T

Abstract:
A method for the production of a multilayer printed circuit board having resinous insulating layers and conductor layers severally bearing a prescribed circuit pattern sequentially superposed on a conductor layer of a circuit board having a prescribed circuit pattern formed in advance thereon, wherein the formation of said resinous insulating layers and conductor layers comprising the steps of:(a) forming a resinous insulating layer on said circuit board by coating the circuit board with a curable resin composition and subjecting the resultant coating to a thermal curing treatment, said curable resin composition being a composition which comprises (A) epoxy resins and (B) an epoxy resin curing agent, said epoxy resins (A) comprising (A-1) a bisphenol a type epoxy resin having an epoxy equivalent of not less than 400 and (A-2) an epoxy resin having an epoxy equivalent of less than 400 and containing at least two epoxy groups in the molecular unit thereof in the ratio of said epoxy resins (A-1:A-2) in the range of from 30:70 to 90:10 by weight so that a cured coating film formed of the resin composition can be partially decomposed or dissolved with a coarsening agent and consequently endowed with an undulating coarsened surface, and said epoxy resin curing agent (B) containing at least two active hydrogen atoms in the molecular unit thereof;(b) treating a surface of the resultant resinous insulating layer with a coarsening agent thereby decomposing more of said epoxy resin (A-1) than said epoxy resin (A-2) with said coarsening agent to impart an undulating coarsened surface to the resinous insulating layer; and(c) forming a conductor layer on the coarsened surface of said resinous insulating layer.