ALKALINE COMPOSITIONS AND PROCESS FOR ETCHING COPPER

摘要

Alkaline etchant solutions for dissolving copper at a controlled relative slow rate, the solution comprising cupric ions as oxidant for metallic copper, sulfamate ions for accelerating appreciably the etching of the copper, and ammonium ions for maintaining the pH of the etchant on the alkaline side of pH and also for complexing dissolved ionic copper. The etchant solutions are especially well adapted for selective etching away of unwanted copper in the manufacture of additive circuit boards.