摘要 |
After the etching away of copper to selectively expose surface areas of insulating resin material in a printed circuit process based upon metal-clad insulating substrate material, the exposed surface areas of insulating material are contacted with a liquid treatment composition effective to soften or swell the resin material such that residual metal species otherwise associated with the surface area are removed or, at the least, become entrapped or encapsulated below a surface of resin, such that the surface insulation resistance afforded by the insulating surface areas of the printed circuit is improved.
|