Method, apparatus and composition for wet etching
A liquid composition for wet etching has improved selectivity for polysilicon over silicon dioxide, even when the polysilicon is heavily doped and/or the silicon dioxide is a low temperature oxide. The composition comprises 0.05-0.4 percent by weight hydrofluoric acid, 15-40 percent by weight nitric...
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Format: | Patent |
Sprache: | chi ; eng |
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Zusammenfassung: | A liquid composition for wet etching has improved selectivity for polysilicon over silicon dioxide, even when the polysilicon is heavily doped and/or the silicon dioxide is a low temperature oxide. The composition comprises 0.05-0.4 percent by weight hydrofluoric acid, 15-40 percent by weight nitric acid, 55-85 percent by weight sulfuric acid and 2-20 percent by weight water. A method and apparatus for wet etching using the composition are also disclosed. |
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