METAL FOIL APPLIED WITH RESIN

摘要

PROBLEM TO BE SOLVED: To realize high density formation of a circuit or mounting while suppressing contraction fluctuation of dimension and reducing thermal expansion/ contraction at the time of multilayer formation by adding a fibrous tiller to an insulation resin being applied to a metal foil which is laminated on a circuit board. SOLUTION: A circuit is formed on a glass cloth basic material epoxy resin copper clad multilayer plate thus producing a circuit board. A metal toil, e.g. a copper foil or an aluminum foil, is employed and a thermosetting resin is dissolved into an amine based solvent to produce a resin dissolved liquid or a fibrous filler is dispersed into the resin dissolved liquid to produce a resin varnish. The resin varnish is applied to the metal foil and thermally dried to form a semi-cured resin layer thus producing a metal toil applied with resin. The metal foil applied with resin is then applied, on the resin surface thereof, to the circuit forming surface of the circuit board and clamped by means of a stainless steel plate. The resin layer applied to the metal foil is fused under specified conditions and flows to fill a circuit pattern and then the resin is set to be molded. An outer layer circuit is formed on the molded multilayer board which is then finished to produce a multilayer printed wiring board.