Abstract: 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.

Abstract: 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.

Abstract: A plating process using an electroless plating bath formed from two separate prepared component solutions. The component solutions mixed within 120 hours prior to plating operations, to provide a highly alkaline plating bath solution. One component solution of the two-part plating bath, is provided with a metal salt or source of plating ions, and which is initially kept in a separate solution from the second other prepared component solution. The second component solution contains formaldehyde, and preferably paraformaldehyde, used to reduce the metal salts into the metal to be deposited on a substrate. Each component solution further includes sodium hydroxide in concentrations selected so that when the two solutions are preferably mixed the final plating bath solution has a pH greater than 11.5.