Patent ID: 6889432
Filing Date: 2005-05-10
Classification: H05K,Y10T

Abstract:
1. A method of manufacturing a double-sided circuit board from a board material constituted by a first electric conductor layer and a first electrically insulating layer formed on one surface of the first electric conductor layer, comprising: a first step of making conduction holes in said board material so that said conduction holes penetrate only said first electrically insulating layer or both said first electrically insulating layer and said first electric conductor layer from predetermined portions of said first electrically insulating layer; a second step of forming an electrically conductive thin-film layer both on a surface of said first electrically insulating layer and on wall surfaces of said conduction holes; a third step of forming a second electrically insulating layer on at least one predetermined portion of said electrically conductive thin-film layer; a fourth step of forming a first electric conductor wiring by plating on a portion of said electrically conductive thin-film layer where said second electrically insulating layer is not formed; a fifth step of covering said first electric conductor wiring with a chemical-resistant film; a sixth step of forming a second electric conductor wiring by chemically dissolving at least one predetermined portion of another surface of said first electric conductor layer in chemicals; and a seventh step of removing said second electrically insulating layer and said chemical-resistant film.