Patent ID: 9516765
Filing Date: 2016-12-06
CPC Classification: H05K,Y10T

Claim Text:
1. A method for producing a printed wiring board, comprising (A) to (F) in this order: (A) laminating, onto an internal layer circuit substrate, a resin sheet with a support which comprises a support and a resin composition layer in contact with the support, so that the resin composition layer is in contact with said internal layer circuit substrate; (B) thermally curing said resin composition layer of said resin sheet with a support to form an insulating layer; (C) perforating said insulating layer to form a via hole; (D) performing a desmear treatment; (E) peeling said support, to expose a surface of said insulating layer; and (F) forming a conductive layer on the surface of said insulating layer, wherein said resin composition layer of said resin sheet with a support comprises at least one epoxy resin, at least one curing agent, and at least one inorganic filler, said at least one curing agent comprises an active ester-based curing agent and a curing agent selected from the group consisting of a phenol-based curing agent and a naphthol-based curing agent, said at least one inorganic filler is treated with at least one surface treatment agent selected from the group consisting of an organosilazane compound, a titanate-based coupling agent, an aminosilane-based coupling agent, an epoxysilane-based coupling agent, and a mercaptosilane-based coupling agent, and said at least one inorganic filler is present in said resin composition layer in an amount of 72% by mass to 95% by mass, when a content of nonvolatile components in said resin composition layer is defined as 100% by mass.