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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1. Verfasser: DETTERBECK, STEFAN
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.