METHOD OF FILLING THROUGH-HOLES

摘要

PROBLEM TO BE SOLVED: To inhibit or reduce dimpling and voids during copper electroplating of through-holes with flash copper layers in substrates such as printed circuit boards.SOLUTION: An aqueous acid solution containing 50 ppb to 10 ppm of disulfide compounds is applied to the through-holes of the substrate, and then the through-holes are filled with copper using an acid copper electroplating bath which includes additives such as brighteners and levelers. (X is sodium, potassium or hydrogen, R is independently hydrogen or alkyl, and n and m are integers equal to or greater than 1.)