ETCHANT FOR COPPER OR COPPER ALLOY, LIQUID FOR ETCHING PRETREATMENT, AND ETCHING METHOD

摘要

Disclosed is an etchant which contains (1) 1-20% by mass of iron (III) chloride and (2) 5-100% by mass of oxalic acid relative to the iron (III) chloride, while containing water as a main component. Also disclosed is an etching method using the etchant. In the etching method, a pretreatment is performed by using an aqueous solution containing at least one component selected from the group consisting of acids and substances dissolving copper or a copper alloy. Consequently, the etching method achieves high yield.