Copper Etching – APS 100 . Standard Operating Procedure . Prepared by: Pauline Stevic Eugene Straver . Date: November 10, 2020 . 1. Purpose and appliion APS100 Copper Etchant is formulated for controlled etching providing fine line definition suitable for thin film circuits. Additionally, compatibility with tin lead solders is assured. At 40˚C, the readyto use solution will etch ...