Process for Etching Metal Oxides U.S. fafenf5,366,516. Ocf. is, 1994 CM. Ashby and D.S. Ginley, assigncm to Sandia Corp., Albuquerque, N. M.

A process for controllably etching at least one of the metal oxides from a mixed metal oxide surface comprising contacting with an aqueous solution of at least one chelating polycarboxylic acid selected from the group consisting of bicarboxylic acids and tricarboxylic acids.

Anti-Tarnish Treatment for Copper US. fatenf5,656,527. Oct. 18, 1994 C-Y Chao and L. Lin, assignors to Olin Cop., New Haven, Corm.

A method for treating a copper or copper-base-alloy foil to impart tarnish resistance thereto, comprising the steps of electrolytically depositing chromium and zinc ions on the foil strip, thereafter rinsing in an aqueous buffer solution containing a material selected from the group consisting of the phosphate salts of an alkali metal or alkaline earth metal, the borate salts of an

alkali metal or alkaline earth metal, or mixtures thereof, said solution having a pH from 5-12, and maintaining the pH by adding an acid during processing.

Electrodepositable Composition U.S. Pateti5,&56,529. CM. i8, 1994 K Eswarakrishnan et al, assignors to PPG lndusfdes Inc., Piffsburgh

An electrodepositable composition com- prising an active hydrogen-containing ionic resin and a capped polyisocyanate curing agent, which contains as an organotin catalyst from 0.025-0.25 percent by weight of tin based on the weight of resin solids.

Copper-Based Metallizations for Hybrid Integrated Circuits U.S. Patent 536,526. Oct. 18, 1994 RR Frankenfha/ et al, assignors to AT&T Bell Laborafories, Murray Hi//, N.J.

A method of forming a circuit including thin film elements and electrical intercon- nections on the major surface of an insulat- ing substrate comprising the steps of depos- iting onto substantially the entire major surface of the substrate a first metal layer

consisting essentially of titanium in a thickness within the range 100-300 nm; depositing onto the first metal layer a second metal layer consisting essentially of an alloy of titanium and palladium in ‘a thickness within the range 50-300 nm; depositing onto the second metal layer a thin metal film consisting essentially of copper in a thickness within the range 300-700 nm; electroplating additional cop- per onto selected portions of the layer of copper in the desired interconnection pat- tern, electroplating a fourth metal layer consisting essentially of nickel on the copper layer utilizing a plating bath com- prising nickel sulfamate; electroplating onto portions of the fourth metal layer a fifth metal layer consisting essentially of gold utilizing a plating bath comprising gold cyanide; removing portions of the copper layer not covered by at least one of the electroplated layers by immersing in an aqueous etching solution comprising am- moniacal solution; and removing portions of the titanium layer and titanium-palla- dium alloy layer not covered by at least one of the electroplated layers by immersing in an aqueous etching solution comprising hydrofluoric acid.

Attent ion Cyanide Platers: Are you troubled by.. . ??carbonate build-up ??pwr efficiency ??reduced brightness ??slow plating rates ??production rejects?

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?? Contains No Caustic or Cyanide - Bath balance is maintained

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CYANIDES PROPRIETARY Copper Cyanide CHEMICALS

Potassium Cyanide WDL #I512 - produces in- Sodium Cyanide visible, corrosion resistant

Zinc Cyanide coating to prevent staining,

COPPER and tarnishing and finger-prints CLEANER #IO5 - alkaline

BRASS ANODES cleaner for soak, electrolytic,

HYDROXIDES or tumble cleaning on cop- per, brass, steel and zinc

Potassium Hydroxide base die castings. Can condi- Sodium Hydroxide tion copper, brass, steel and

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METAL FINISHING . APRIL 1995 101