Selective etching method and apparatus
First Claim
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1. A dry etching method, comprising:
- providing a workpiece that supports silicon nitride and silicon dioxide; and
exposing the workpiece to a plasma containing (i) at least a selected one of sulfur hexafluoride and nitrogen trifluoride and (ii) ammonia to selectively etch the silicon nitride in relation to the silicon dioxide with a given selectivity and introducing no other gases into the plasma which would produce an appreciable effect on the given selectivity.
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Abstract
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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Citations
29 Claims
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1. A dry etching method, comprising:
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providing a workpiece that supports silicon nitride and silicon dioxide; and exposing the workpiece to a plasma containing (i) at least a selected one of sulfur hexafluoride and nitrogen trifluoride and (ii) ammonia to selectively etch the silicon nitride in relation to the silicon dioxide with a given selectivity and introducing no other gases into the plasma which would produce an appreciable effect on the given selectivity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 27, 28, 29)
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14-26. -26. (canceled)
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