Method of purifying alkaline solution and method of etching semiconductor wafers
US6319845A · kind A · utility
3Cited by
11References
8Claims
0Family size
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Key dates
| Filing date | Mar 2, 1998 |
| Grant date | Nov 20, 2001 |
| Priority date | — |
| Expiry date | Mar 2, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01D1/28
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method of purifying an alkaline solution is capable of extremely efficiently nonionizing metallic impurity ions in an alkaline solution at a low cost. A method of etching semiconductor wafers in turn is capable of etching semiconductor wafers using the purified alkaline solution without deteriorating the quality of the semiconductor wafers. A reducing agent having an oxidation potential lower than a reversible electrode potential of metallic ions existing in the alkaline solution is dissolved in the alkaline solution to thereby nonionize the metallic ions existing in the alkaline solution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.