SEMICONDUCTOR PACKAGE UNIT

摘要

A package unit constituting a semiconductor package having at least twice the capacity. The both faces of a clad plate (34) are selectively etched using as a wet etchant an aqueous solution consisting of a combination of one or two or more of ferric chloride, copper (II) chloride, and sulfuric acid plus hydrogen peroxide to form a base having an inner conductor layer, an insulation layer and an outer conductor layer are formed on the outer surface of the base, the outer conductor layer is patterned, and the inner and outer conductor layers are electrically connected, via a columnar conductor formed in the base by etching, with semiconductor chips (1, 2) mounted on the both faces of the clad plate, thereby forming an integral-structure semiconductor package unit.