The present invention provides a method for producing high density electronic circuit boards comprising the steps of depositing a layer of a first metal upon a layer of foil to produce a composite then attaching the composite to an insulative support to produce a laminate. The layer of foil is then removed from the layer of first metal. Photoresist is then applied to the layer of first metal, exposed and developed. During the development of the photoresist portions of the photoresist are removed from the layer of first metal. A layer of third metal is then plated upon the portions of the layer of first metal that are not covered by the photoresist. All remaining photoresist and the portions of the layer of first metal which are not covered by the third metal are then removed producing a finished fine-line pattern having conductive and insulative areas. The finished fine-line pattern may then be utilized to produce a circuit board.
The present invention provides a new and improved titanium metal drum cathode for use in the production of metal foils and a novel method of making the same. The method includes the steps of welding together the ends of a strip of titanium that has been roll formed into a cylinder. During the welding operation some of the weld beads that form the weld are hot peened immediately upon solidification. Upon complete formation of the weld, the formed and welded trip of titanium is subjected to a heat treating cycle that includes a double anneal. Preferably, the strip of titanium metal and the weld metal that is used to form the weld both comprise an addition agent such as yttria.
A wiring board is fabricated through the following steps: (A) forming, on one side of an elongated carrier metal foil made of a first metal, a thin layer with a second metal whose etching conditions are different from those of the first metal; (B) forming, on a surface of the thin layer, a desired wiring pattern with a third metal whose etching conditions are different from those of the second metal; (C) superposing the carrier metal foil on an insulating substrate with the side of the wiring pattern being positioned inside, whereby the wiring pattern is embedded in the insulating substrate; and (D) etching off the carrier metal foil and the thin layer at desired parts thereof.
There is provided a flexible printed wiring board including an insulating layer having a high optical transmittance, a high adhesion strength and a high migration resistance, and suitable for a chip on film (hereafter referred to as COF). In a flexible printed wiring board for COF, having an insulating layer on which a conductive layer of an electrodeposited copper foil is laminated, and an optical transmittance of 50% or more of the insulating layer in the etched region when a circuit is formed by etching said conductive layer, electrodeposited copper foil was made to have a rust-proofing layer of a nickel-zinc alloy on the adhering surface to be adhered to the insulating layer; the surface roughness (Rz) of the adhering surface was made to be 0.05 to 1.5 .mu.m, and the specular gloss was made to be 250 or more when the incident angle is 60.degree..
The present invention provides a new and improved titanium metal drum cathode for use in the production of metal foils and a novel method of making the same. The method includes the steps of welding together the ends of a strip of titanium that has been roll formed into a cylinder. During the welding operation some of the weld beads that form the weld are hot peened immediately upon solidification. Upon complete formation of the weld, the formed and welded trip of titanium is subjected to a heat treating cycle that includes a double anneal. Preferably, the strip of titanium metal and the weld metal that is used to form the weld both comprise an addition agent such as yttria.
This invention relates to a process for applying a stabilization layer to at least one side of copper foil comprising contacting said side of said copper foil with an electrolyte solution comprising zinc ions, chromium ions and at least one hydrogen inhibitor. This invention also relates to copper foils treated by the foregoing process, and to laminates comprising a dielectric substrate and copper foil treated by the foregoing process adhered to said dielectric substrate.
