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Chemically Prepared Oxide Free Surface For Nickel Iron Alloys

IP.com Disclosure Number: IPCOM000048637D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Gardner, MJ: AUTHOR [+3]

Abstract

This article concerns a specific method for preparing nickel-iron alloy foils for photoresist adhesion in connection with the processing of such foils for the fabrication of thin metal masks. Such masks are useful in photolithographic processes for producing and testing integrated circuit structures in other substrates.

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Chemically Prepared Oxide Free Surface For Nickel Iron Alloys

This article concerns a specific method for preparing nickel-iron alloy foils for photoresist adhesion in connection with the processing of such foils for the fabrication of thin metal masks.

Such masks are useful in photolithographic processes for producing and testing integrated circuit structures in other substrates.

Earlier processes for preparing such thin alloy foils usually involved a series of oxidization and etching steps whereby the foil surface would first be oxidized-- by exposure to an alkali or to an etchant such as ferric chloride--and then subjected to an acid treatment to remove dark metallic oxides remaining on the surface. Then the foil would be rinsed in DI (distilled water).

Presently, this can be accomplished in fewer operational steps. An aqueous solution of sodium persulfate (NA(2)S(2)O(8)) and sulfuric acid (H(2)S0(4)) has been found to generate a uniform oxide-free foil surface. Since the products of this reaction are highly soluble in water, no oxides remain on the surface, thereby eliminating the need for a secondary acid treatment. A DI water rinse in all that is needed.

The solution was found to work over a wide range of concentrations, as listed below, made up to 1 liter with DI water. 5-20 percent sodium persulfate

5-10 percent sulfuric acid

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