Rolled copper foil or electrolytic copper foil for electronic circuit, and method of forming electronic circuit using same

Abstract

Provided is a rolled copper foil or electrolytic copper foil for an electronic circuit to be used for forming a circuit by etching, wherein the copper foil comprises a heat resistance layer composed of zinc or zinc alloy or its oxide formed on an etching side of the rolled copper foil or electrolytic copper foil, and a layer of nickel or nickel alloy, which is a metal or alloy with a lower etching rate than copper, formed on the heat resistance layer. This invention aims to prevent sagging caused by the etching, to form a uniform circuit having the intended circuit width, and to shorten the time of forming a circuit by etching as much as possible, when forming a circuit by etching a copper foil of the copper-clad laminate; and also aims to make the thickness of the nickel or nickel alloy layer as thin as possible, to inhibit oxidation when exposed to heat, to prevent tarnish (discoloration) known as 'YAKE', to improve the etching properties in pattern etching, and to prevent the occurrence of short circuits and defects in the circuit width.