Etchant mixing system for edge bevel removal of copper from silicon wafers
US6333275A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 2000 |
| Grant date | Dec 25, 2001 |
| Priority date | — |
| Expiry date | Apr 25, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/67051
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A chemical etching system provides a mixture of sulfuric acid and hydrogen peroxide and serves as the etchant for removing residual copper from an edge bevel region of a semiconductor wafer. The etching system includes a dilution module where concentrated sulfuric acid and concentrated hydrogen peroxide are diluted to the appropriate concentrations and then stored. To reduce the likelihood that oxygen bubbles (from hydrogen peroxide decomposition) will appear in the etchant solution, stored sulfuric acid and hydrogen peroxide are mixed immediately prior to use. In this manner, the dissolved oxygen concentration in the hydrogen peroxide decreases well below the saturation level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.