摘要 |
A dry etching method and apparatus are described. A workpiece supports silicon nitride and silicon dioxide. The workpiece is exposed to a plasma containing at least one of sulfur hexafluoride and nitrogen trifluoride and ammonia to selectively remove the silicon nitride in relation to the silicon dioxide. In one feature, the plasma contains sulfur hexafluoride and ammonia. In another feature, the plasma contains nitrogen trifluoride and ammonia.
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