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Removal of Contamination Left From Reactive Ion Etching of Si Wafers Without Simultaneous Oxide Growth

IP.com Disclosure Number: IPCOM000102078D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Related People

Clabes, JG: AUTHOR [+2]

Abstract

Disclosed is a process for cleaning off reactive ion etching induced fluorocarbon residues by using a plasma of a feed gas mixture of oxygen (O2) and a noble gas.

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Removal of Contamination Left From Reactive Ion Etching of Si Wafers Without Simultaneous Oxide Growth

       Disclosed is a process for cleaning off reactive ion
etching induced fluorocarbon residues by using a plasma of a feed gas
mixture of oxygen (O2) and a noble gas.

      Using a combination of O2 and noble gases in a plasma enhances
the effectiveness of the cleaning process over that of pure O2 or
pure noble gas.  The removal process due to oxygen species is
dominated by chemical reaction with the surface constituents whereas
noble gas atoms remove material via physical sputtering.
Oxygen-related reactive radicals are particularly effective in
removing carbonaceous surface impurities since volatile species are
produced in the process.  The formation of stable SiO2 at the surface
prevents impurities imbedded in the surface to be effectively
removed.  The physical sputtering by noble gas ions in the plasma
inhibits the growth of the SiO2 passivation layer and enables the
chemical-assisted removal process to continue, in contrast to a pure
oxygen plasma process where an additional HF dip is required to
remove the oxide layer.  Upon optimization of the relative
concentration in the gas mixture, no post treatment is required.

      Since the sputter yield for noble ions on carbon is at least,
by a factor of three, smaller than for Si or SiO2, noble ion
bombardment is not an effective removal process for carbonaceous
surface films.  The higher energy io...