Process for producing multilayer printed circuit boards

摘要

An etching solution comprising (A) an amine as a solvent, (B) an alkali metal compound, and (C) an alcohol as a solvent, this etching solution being a non-aqueous solution. This etching solution is-effective for etching a cured epoxy resin layer for forming holes for interstitial via holes having a small diameter, in the production of a multilayer printed circuit board. This etching solution is particularly effective for etching a cured epoxy resin layer formed from a thermosetting epoxy resin composition including (a) an epoxy resin, (b) a crosslinking agent, and (c) a polyfunctional epoxy resin, which forms a thermosetting copper-clad adhesive resin sheet which covers an interlayer circuit plate of a multilayer printed circuit board.