Browse Prior Art Database

A Coating for Plasma Processing Tools to Reduce Metal Contamination

IP.com Disclosure Number: IPCOM000103023D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 56K

Publishing Venue

IBM

Related People

Desilets, BH: AUTHOR [+3]

Abstract

This article describes the application of tufram (PTFE impregnated aluminum oxide) to the walls of a plasma etching reactor confinement can to reduce heavy metal contamination of work product caused by sputtering action. Such contamination results in crystalline defects, dislocations and increased device leakage currents. Also, with quartz reactive ion etch (RIE), it causes a micromask to form on the quartz surface, making the quartz underneath more difficult to etch, and covered with remnant residues.

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A Coating for Plasma Processing Tools to Reduce Metal Contamination

      This article describes the application of tufram (PTFE
impregnated aluminum oxide) to the walls of a plasma etching reactor
confinement can to reduce heavy metal contamination of work product
caused by sputtering action.  Such contamination results in
crystalline defects, dislocations and increased device leakage
currents.  Also, with quartz reactive ion etch (RIE), it causes a
micromask to form on the quartz surface, making the quartz underneath
more difficult to etch, and covered with remnant residues.

      Due to high plasma potentials (above sputtering threshold), a
plasma can cause sputtering of the reactor walls.  This has been
found to occur in plasma etching diode reactors unless the plasma
potential is reduced below 20 volts.  If stainless steel, or alloys
containing heavy metal impurities are used in the confinement can,
such as is the case with batch diode reactors, heavy metals (Fe, Cr,
Ni, etc.) contamination of semiconductor wafers will occur during
semiconductor device fabrication.  Present equipments, e.g., batch
RIE diode reactors, etc., use a plasma confinement can made of an
aluminum alloy containing Fe and Ni, contributing to the heavy metals
contamination problem.

      A hard coating of tufram, which is PTFE impregnated aluminum
oxide (A1203), was applied to the aluminum confinement can to
effectively minimize such contamination. The tufram coating was
formed...