Selective wet etching of gold-tin based solder
US8617997B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 21, 2007 |
| Grant date | Dec 31, 2013 |
| Priority date | — |
| Expiry date | Aug 21, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H20/01
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The present invention is directed to post-deposition, wet etch processes for patterning AuSn solder material and devices fabricated using such processes. The processes can be applied to uniform AuSn layers to generate submicron patterning of thin AuSn layers having a wide variety of features. The use of multiple etching steps that alternate between different mixes of chemicals enables the etch to proceed effectively, and the same or similar processes can be used to etch under bump metallization. The processes are simple, cost-effective, do not contaminate equipment or tools, and are compatible with standard cleanroom fabrication processes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.