Acidic aqueous binary silver-bismuth alloy electroplating compositions and methods
OwnerMiguel A. Rodriguez, Michael Lipschutz +2inventors
InventorsMiguel A. Rodriguez, Michael Lipschutz, Jamie Y.C. Chen, Youngmin Yoon
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Abstract
Aqueous acid binary silver-bismuth alloy electroplating compositions and methods enable electroplating silver rich binary silver-bismuth deposits. The aqueous acid binary silver-bismuth alloy electroplating compositions include 5-membered heterocyclic nitrogen compounds with a thiol functionality which enable deposition of the silver rich binary silver-bismuth alloys. The silver rich silver-bismuth deposits are matte to semi-bright, uniform and have a low coefficient of friction.
Claims11
A binary silver-bismuth alloy electroplating composition comprising a source of silver ions, a source of bismuth ions, and a 5-membered aromatic heterocyclic nitrogen compound having a general formula:
- wherein Q1-Q4 can be a substituted or unsubstituted nitrogen or a substituted or unsubstituted carbon with the proviso that at least two of Q1-Q4 are nitrogen, wherein substituent groups include, but are not limited to, (C1-C4)alkyl, amino group, aminoalkyl group, carboxyl, carboxy(C1-C4)alkyl or alkylsulfonate, and a pH of less than 7.
A method of electroplating a binary silver-bismuth alloy on a substrate comprising:
- a) providing the substrate;
- b) contacting the substrate with a binary silver-bismuth alloy electroplating composition comprising a source of silver ions, a source of bismuth ions, and a 5-membered aromatic heterocyclic nitrogen compounds having general formula:
- wherein Q1-Q4 can be a substituted or unsubstituted nitrogen or a substituted or unsubstituted carbon with the proviso that at least two of Q1-Q4 are nitrogen, wherein substituent groups include, but are not limited to, (C1-C4)alkyl, amino group, aminoalkyl group, carboxyl, carboxy(C1-C4)alkyl or alkysulfonate, and a pH of less than 7;
- and
- c) applying an electric current to the binary silver-bismuth alloy electroplating composition and substrate to electroplate a binary silver-bismuth deposit on the substrate.
An article comprising a binary silver-bismuth alloy layer adjacent a surface of a substrate, wherein the binary silver-bismuth alloy layer comprises 90% to 99.8% silver and 0.2% to 10% bismuth, and has a coefficient of friction of 1 or less.
Dependencies are inferred from the claim text.