Abstract: There is disclosed a treating process whereby the thermal oxidation resistance on the shiny side of a copper foil is enhanced so that the shiny side will not discolor on heating to higher temperatures than usual, without impairing the foil's solder wettability, adhesion to resist, and other properties. A Zn-Ni alloy layer which comprises 50-97 wt % Zn and 3-50 wt % Ni or a Zn-Co alloy layer which comprises 50-97 wt % Zn and 3-50 wt % Co is formed on the shiny side of a copper foil at a deposition quantity of 100-500 .mu.g/dm.sup.2 and then the alloy surface is treated for Cr-base corrosion-preventive coating. The Cr-base corrosion-preventive treatment comprises (1) a treatment for forming a coating film of chromium oxide alone, (2) a treatment for forming a mixed coating film of chromium oxide and zinc and/or zinc oxide or (1)+(2). The roughened side of the copper foil may be treated to form thereon a layer of single metal or alloy of two or more metals chosen from among Cu, Cr, Ni, Fe, Co, and Zn.

Abstract: There is provided a copper foil for printed circuits characterized by having a coating layer which contains zinc and zinc oxide, chromium oxide and nickel, and either or both of zinc and zinc oxide at least on the shiny side of a copper foil. The coating layer is formed by electroplating using a plating solution which contains either or both of zinc salt and zinc oxide, chromic salt and nickel salt. This copper foil resists discoloration upon exposure to high-temperature conditions of 180.degree. C. for 30 minutes. Resist adhesion is also good. The amounts of deposits are preferably 60 to 80 .mu.g Zn, 30 to 40 .mu.g Cr and 5 to 20 .mu.g Ni per dm.sup.2. The matt side of the copper foil may be treated to form thereon a single metal layer or alloy layer of one or more metals chosen from among Cu, Cr, Ni, Fe, Co, and Zn. The copper foil is suited for the fabrication of printed circuits with fine circuit patterns.

Abstract: A copper foil for printed circuits has a roughened layer formed on the side of the foil to be bonded to a base, the roughened layer consisting of a number of protuberant copper electrodeposits containing chromium tungsten or both. It may also have a copper plating layer covering the roughened layer and a treatment layer covering the copper plating layer and formed of either a metal selected from the group consisting of copper, chromium, nickel, iron, cobalt, and zinc, or an alloy of two or more such metals. When necessary, the copper foil may contain an anticorrosive layer including various chromate treated layers further formed on the treatment layer. The copper foil is produced by electrolyzing a raw foil as a cathode in an acidic copper electrolytic bath at a current density close to the critical density, thereby forming the roughened layer, the electrolytic bath containing 0.001-5 g/l of chromium ion tungsten ion or both.

Abstract: In a method of producing an electrolytic copper foil by passing an electrolyte between a rotating cathode drum and anode located opposite to the cathode drum, the thickness of the resulting copper foil is made uniform throughout. The anode has a structure including a main portion and an end portion, the end portion being divided widthwise into n foil thickness-uniformizing sub-anodes. Electricity is supplied to the main anode and the sub-anodes at a preset current density D (A/dm.sup.2) to attain a target foil thickness T (g/m.sup.2). Variations of thickness in the direction of the width of the resulting copper foil are measured as the thicknesses Tm (g/m.sup.2) where m=1-n in the direction of the width of the copper foil corresponding to the n sub-anodes, and the quantities of electricity being supplied to the n sub-anodes are individually controlled at current densities Dm (A/dm.sup.2) where m=1-n so that Tm values are made equal to the target foil thickness T (g/m.sup.2).

Abstract: A process for the treatment of a copper foil for printed circuits comprises forming, over the surface of the copper foil to be treated, of an electroplating alloy deposit selected from the group consisting of electroplating deposits of binary alloys composed of 20-40 mg/dm.sup.2 copper and 100-3000 .mu.g/dm.sup.2 cobalt and of ternary alloys of 20-40 mg/dm.sup.2 copper, 100-3000 .mu.g/dm.sup.2 cobalt, and 100-1000 .mu.g/dm.sup.2 nickel. The copper foil treated has heat resistance, peel strength, and resistance to hydrochloric acid comparable to the Cu-Ni-treated foils. It can be etched with a CuCl.sub.2 etchant to form 150 .mu.m or finer-pitch printed circuits and is also etchable with alkalies. Its magnetizability is below the permissible upper limit.