METHOD OF MANUFACTURING SMALL SIZE THROUGH HALL FOR PRINTED CIRCUIT BOARD

摘要

A method for forming a small through hole on a printed circuit board is provided to relieve a thermal load applied to a base copper foil by opening a copper foil of a processing surface and an opposite surface at the same time. A dry film is coated on a surface of a top copper foil(39) and a bottom copper foil(40). The dry film is etched in order to expose the top copper foil and the bottom copper foil of a part for forming a through hole. The exposed top and bottom copper foils are opened. An insulation layer is selectively opened in the top copper foil. The insulation layer is etched by a laser beam irradiation in order to form a through hole. A copper plating(70) is performed in an inner wall of the top copper foil, the bottom copper foil, and the through hole. The through hole is filled by a solder ink.