Method of filling through-holes

摘要

The methods inhibit or reduce dimpling and voids during copper electroplating of through-holes with flash copper layers in substrates such as printed circuit boards. An acid solution containing reaction products of aromatic heterocyclic nitrogen compounds and epoxy-containing compounds is applied to the through-holes of the substrate followed by filling the through-holes with copper using a copper electroplating bath which includes additives such as brighteners and levelers.