Anisotropic silicon etching in fluorinated plasma
First Claim
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1. A mehtod of anisotropically etching a silicon body in a single etching step, comprising:
- placing said silicon body in a gaseous plasma environment at a constant gas pressure and composition consisting essentially of a chlorine-free fluorine-containing etchant gas, and a polymer-forming gas for substantially limiting lateral etching of said silicon body, said polymer-forming gas consisting of one or more halogenated hydrocarbons wherein the halogen in each is fluorine.
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Abstract
A method of high rate anisotropic etching of silicon in a high pressure plasma is described. In one embodiment the etching ambient is a mixture of either NF3 or SF6, an inert gas such as nitrogen, and a polymerizing gas such as CHF3 that creates conditions necessary for anisotropy not normally possible with nonpolymerizing fluorinated gases in a high pressure regime. The etch process is characterized by high etch rates and good uniformity utilizing photoresist or similar materials as a mask. The present process may advantageously be used to etch deep trenches in silicon using a photoresist mask.
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7 Claims
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1. A mehtod of anisotropically etching a silicon body in a single etching step, comprising:
placing said silicon body in a gaseous plasma environment at a constant gas pressure and composition consisting essentially of a chlorine-free fluorine-containing etchant gas, and a polymer-forming gas for substantially limiting lateral etching of said silicon body, said polymer-forming gas consisting of one or more halogenated hydrocarbons wherein the halogen in each is fluorine. - View Dependent Claims (2, 3, 4, 5)
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6. A method of anisotropically etching a silicon body in a single etching step, comprising:
placing said silicon body in a gaseous plasma environment at a constant gas pressure and composition consisting essentially of an inert gas, and a chlorine-free fluorine-containing etchant gas, and a polymer-forming gas for substantially limiting lateral etching of said silicon body, said polymer-forming gas consisting of one or more halogenated hydrocarbons wherein the halogen in each is fluorine. - View Dependent Claims (7)
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