COPPER PLATING METHOD OF VIA HOLE

摘要

PURPOSE: To complete filling plating inside a via hole with ensured reliability in a short time, even if a hole diameter becomes as a small as 40 μm. CONSTITUTION: After chemical copper plating is applied to an inner surface of a via hole connecting upper and lower conductor layers of a multilayer substrate, the inside of a via hole is subjected to filling plating by electrolytic copper plating. The electrolytic copper plating is carried out first, at a low- current density of 1.5 A/dm¬2 or lower in an allowable current range of plating bath and thereafter the remaining plating is carried out at a higher current density (for example, 3A/dm¬2). Electrolytic copper plating is carried out by alternating positive pulse and negative pulse through pulse plating, whose energization amount of positive pulse is set large. Ratio t1/t2 of an energization time t1 for positive pulse and an energization time t2 for negative pulse is 40/2 and the ratio F/R of a current value F of positive pulse and a current value R of negative pulse is 1/3.