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

摘要

An etchant for copper or copper alloy, which contains water as a main component and comprises (1) 1 to 20 mass % of iron (III) chloride and (2) 5 to 100 mass %, based on the iron chloride, of oxalic acid, and an etching method using the above etchant are provided, and the etching method includes pretreatment to be carried out with an aqueous solution containing at least one component selected from a component that dissolves copper or copper alloy and an acid, whereby well yields can be materialized.