Browse Prior Art Database

Method for Magnetic Enhanced Reactive Ion Etch of Uniform Trench Structures on VLSI Circuits

IP.com Disclosure Number: IPCOM000104037D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 47K

Publishing Venue

IBM

Related People

Lii, YT: AUTHOR [+2]

Abstract

Disclosed is a method for uniform etching of trench structure on VLSI circuits by using a magnetic enhanced reactive ion etcher. The method utilizes the unbalanced local loading to compensate trench sidewall passivation during trench etch to increase profile uniformity. Control of the etched trench sidewall angle on VLSI circuits is often desired. Halogen gas and oxygen mixture is usually used as main chemicals for magnetic enhanced reactive ion etch of single crystal silicon. Oxygen primarily promotes the sidewall passivation on the etched trench by reacting with etched silicon in plasma during etch. By increasing oxygen concentration, a decrease of the lateral undercut and smoother sidewall are observed due to higher sidewall passivation rate.

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Method for Magnetic Enhanced Reactive Ion Etch of Uniform Trench Structures on VLSI Circuits

      Disclosed is a method for uniform etching of trench structure
on VLSI circuits by using a magnetic enhanced reactive ion etcher.
The method utilizes the unbalanced local loading to compensate trench
sidewall passivation during trench etch to increase profile
uniformity.
     Control of the etched trench sidewall angle on VLSI circuits is
often desired.  Halogen gas and oxygen mixture is usually used as
main chemicals for magnetic enhanced reactive ion etch of single
crystal silicon.  Oxygen primarily promotes the sidewall passivation
on the etched trench by reacting with etched silicon in plasma during
etch.  By increasing oxygen concentration, a decrease of the lateral
undercut and smoother sidewall are observed due to higher sidewall
passivation rate.  The edge effects of reactor and ununiform
distribution of passivated materials usually results in an ununiform
passivation which produces a center to edge profile variation of
approximately 2-5 degrees with the trench at center of wafer more
vertical than the edge at all ranges of process conditions.  This
method is the introduction of extra silicon source at the edge of
wafer during the etching process to induce a higher passivation rate
at the edge of wafer to compensate intrinsic ununiform passivation.
One method of achieving this would be by exposing the unused wafer
area at the edge of a wafer to let this ext...