Via hole structure and process for formation thereof

摘要

A via hole structure for interlayer connection formed in an insulating film and a process for the formation of the same. Via holes are formed in an insulating film of a multilayer interconnected board or the like so as to have a shape such that when a metallic film for wiring is formed on the insulating film, the metal film can completely fill up the via holes. The via holes are formed by gradually increasing from the bottom toward the top of an insulating layer 8 the apertures of the via holes 7 formed in the insulating layer 8, comprised of a plurality of insulating resin film or photosensitive insulating resin film layers 2, 5, in a multilayer interconnected board comprising the insulating layer 8 laminated alternately with a wiring layer 13 comprised of an electric conductor.