Electroplating solution for gold-tin eutectic alloy
US7431817B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 2005 |
| Grant date | Oct 7, 2008 |
| Priority date | — |
| Expiry date | May 10, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC25D3/62
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The invention relates to an electrolyte used in connection with the deposition of a gold-tin alloy on an electroplatable substrate. This solution generally includes water; stannous and/or stannic tin ions, a complexing agent to render the stannous and/or stannic tin ions soluble, complexed gold ions, and an alloy stabilizing agent that includes ethoxylated compounds with phosphate ester functional group, brightening additives based on ethoxylated phosphate esters and alkali metal fatty acids dipropionates. The brighteners may be used alone or in conjunction with each other to achieve beneficial synergistic effect. The alloy stabilizing agent is present in an amount sufficient to stabilize the composition of the gold-tin deposit over a usable current density range. The solution has a pH of between 2 and 10 and the gold ions and tin ions are present in relative amounts sufficient to provide a deposit having a gold content less than 90% by weight and a tin content greater than 10% by weight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.