Circuit board featuring a structure with thick copper on hole and method for manufacturing the same

摘要

PROBLEM TO BE SOLVED: To provide a method of manufacturing a circuit board having a structure where only a conduction layer above a hole is thick, by forming a high density circuit while thickening the conduction layer above a hole, e.g., a through hole, without thickening a copper plating layer excepting a hole.SOLUTION: A method of manufacturing a circuit board having a structure where a conduction layer immediately above a through hole is thicker than the conduction layer on the outer periphery of a through hole comprises: (1) a step of forming a copper clad laminate with a through hole; (2) a step of forming a copper clad laminate with a conduction through hole; (3) a step of forming a non-through conduction through hole by filling the conduction through hole with a filler; (4) a step of making the surface of the non-through conduction through hole concave by irradiation with a laser beam; and (5) a step of flattening the concave part by giving a copper plating layer to both sides of the copper clad laminate which is made concave, and making flush with the copper clad laminate.