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Biased Metallic Grid for Avoidance of Heavy Metal Sputtering And Improvement of Chamber Wall Cleaning for Reactive Ion/Plasma Etch or Sputtering Apparatus

IP.com Disclosure Number: IPCOM000102067D
Original Publication Date: 1990-Oct-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 51K

Publishing Venue

IBM

Related People

Oehrlein, GS: AUTHOR

Abstract

Disclosed is a chamber configuration for plasma processing which utilizes a biased metallic grid to control heavy metal sputtering from chamber walls and improves the efficiency of chamber wall cleaning procedures.

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Biased Metallic Grid for Avoidance of Heavy Metal Sputtering And Improvement of Chamber Wall Cleaning for Reactive Ion/Plasma Etch or Sputtering Apparatus

       Disclosed is a chamber configuration for plasma
processing which utilizes a biased metallic grid to control heavy
metal sputtering from chamber walls and improves the efficiency of
chamber wall cleaning procedures.

      A thin metallic grid is attached to the inner walls of a
reactive ion etch, plasma etch or sputtering apparatus. The metallic
grid is electrically isolated from the walls and any other inner
surfaces of the chamber.  For most pressures a distance of 1-4 mm
between the wall and the grid is appropriate.  Although the grid
dimensions need to be optimized for particular applications, a wire
thickness of 0.1 mm  and a wire spacing of 1 mm is a reasonable first
choice.  The material of the grid should be non-reactive with the
etch chemistry.  An aluminum grid can be used for fluorine-based
plasmas since A1F3 is involatile.  Aluminum covered with a thin layer
of aluminum-oxide or silicon-dioxide can be used for
chlorine/fluorine-based chemistries.  If the grid is held at ground
potential, the plasma sheath will terminate at the grid.  Therefore,
ions will not be accelerated once they have passed the grid and, at
appropriate pressures, their energies will be reduced by gas phase
collisions.  The reduced ion energy results in reduced sputtering of
wall material.  Since the metallic grid ...