Dry etching method by sulfur conditioning
First Claim
1. A dry etching method comprising the steps ofgrowing sulfur from a gaseous phase on at least a part of the inner wall surface of an etching chamber, andetching a layer of a silicon-based material on a wafer using an SF6 containing etching gas during sublimation of said sulfur.
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Abstract
A method for anisotropic etching of a layer of a silicon-based material, using an SF6 gas, a versatile etching gas, is proposed. Sulfur (S) is used as a sidewall protection substance. This sulfur is not supplied into an etching reaction system on discharge dissociation of the etching gas, but is supplied by being sublimed off on heating from the inner wall surface of the etching chamber on which it is previously grown from a gaseous phase. Specifically, the S2 F2 gas is introduced while a predetermined region of the inner wall surface of the etching chamber is cooled, and preliminary discharge is carried out to deposit sulfur on the region. A SF6 containing etching gas is introduced into the chamber and the above mentioned region is heated for subliming S and simultaneously etching the layer of the silicon-based material. With this method, there is no necessity of using a specific etching gas capable of yielding free S in the plasma under discharge dissociating conditions. The present invention has an important significance as post-CFC (chlorofluorocarbon) gas measures. After end of etching, sulfur may be easily sublimed off by heating the wafer without the risk of pollution by particles.
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Citations
5 Claims
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1. A dry etching method comprising the steps of
growing sulfur from a gaseous phase on at least a part of the inner wall surface of an etching chamber, and etching a layer of a silicon-based material on a wafer using an SF6 containing etching gas during sublimation of said sulfur.
Specification