Plasma etch chemistry for anisotropic etching of silicon
First Claim
1. The method for selectively etching a layer of a silicon-bearing material in an integrated circuit, comprising the steps of:
- providing a patterned masking material over said silicon-bearing material to expose only the areas of said silicon-bearing material which are to be etched;
passing a gaseous mixture over said layer; and
creating a plasma discharge in said gaseous mixture adjacent to said layer of silicon-bearing material;
wherein said gaseous mixture comprises bromine and a chlorine-bearing species.
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Abstract
A plasma etch chemistry which allows a near perfectly vertical etch of silicon is disclosed. A Cl-containing compound such as BCl3 has Br2 added to it, readily allowing anisotropic etching of silicon. This is due to the low volatility of SiBr4. The silicon surface facing the discharge is subjected to ion bombardment, allowing the volatilization (etching) of silicon as a Si-Cl-Br compound. The Br which adsorbs on the sidewalls of the etched silicon protects them from the etching. This new plasma etch chemistry yields a very smooth etched surface, and the etch rate is relatively insensitive to the electrical conductivity of the silicon.
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Citations
17 Claims
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1. The method for selectively etching a layer of a silicon-bearing material in an integrated circuit, comprising the steps of:
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providing a patterned masking material over said silicon-bearing material to expose only the areas of said silicon-bearing material which are to be etched; passing a gaseous mixture over said layer; and creating a plasma discharge in said gaseous mixture adjacent to said layer of silicon-bearing material; wherein said gaseous mixture comprises bromine and a chlorine-bearing species. - View Dependent Claims (3, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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2. The method for selectively etching a layer of a silicon-bearing material in an integrated circuit, comprising the steps of:
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providing a patterned masking material over said silicon-bearing material to expose only the areas of said silicon-bearing material which are to be etched; passing a gaseous mixture over said layer; and creating a plasma discharge in said gaseous mixture adjacent to said layer of silicon-bearing material; wherein said gaseous mixture comprises bromine, a fluorine-bearing species, and a chlorine-bearing species. - View Dependent Claims (4, 5)
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Specification