Process for electroless deposition of gold and gold alloys on silicon

摘要

A plating bath for electroless deposition of gold and gold alloy layers on such silicon-based substrates, includes Na(AuCl4) and/or other gold (III) chloride salts as a gold ion source. The bath is formed as a binary bath solution formed from mixing first and second bath components. The first bath component includes gold salts in concentrations up to 40 g/L, boric acid, in amounts of up to 30 g/L, and a metal hydroxide in amounts up to 20 g/L. The second bath component includes an acid salt, in amounts up to 25 g/L, sodium thiosulfate in amounts up to 30 g/L, and suitable acid, such as boric acid in amounts up to 20 g/L.

主权项

1. A process for electroless coating gold or gold alloy on a substrate comprising:
preparing a plating bath comprising, a first bath component, a second bath component, and a reducing agent,
the first bath component comprising,
about 0.75 to 5 g/L Na(AuCl4),about 1 to 15 g/L H3BO3, andup to 3 g/L NaOH,the second bath component comprising,
about 1 to 20 g/L Na2SO3,about 5 to 25 g/L Na2S2O3, andabout 3 to 20 g/L H3BO3, immersing said substrate in said plating bath.