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Novel Pad Conditioning Technology for Polishing Wafers

IP.com Disclosure Number: IPCOM000112176D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Burke, PA: AUTHOR

Abstract

A conditioning procedure is described that prolongs the life of pads used for polishing semiconductor wafers. A conditioning rinse with pH near that of the polishing slurry is sprayed through a nozzle into the pad while scraping the pad with a mildly abrasive surface.

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Novel Pad Conditioning Technology for Polishing Wafers

      A conditioning procedure is described that prolongs the life of
pads used for polishing semiconductor wafers.  A conditioning rinse
with pH near that of the polishing slurry is sprayed through a nozzle
into the pad while scraping the pad with a mildly abrasive surface.

The slurry effluent that would otherwise clog the pores of the pad is
removed with very little pad erosion.

Three techniques are key to the conditioning procedure:

1.  The pH of the conditioning rinse must be nearly that of the
    slurry being used.

2.  The spray must act in such a way as to pressurize the pad pores
    while conditioning.  This may be accomplished by pushing a
    pressurized spray nozzle into direct contact with the polishing
    pad.

3.  Use of a mildly abrasive pad scrub such as 70 micron grit
    diamond.

      In the Figure, the nozzle is shown nearly flush with the pad so
that most of the spray nozzle pressure (P2) is applied to the pad
pores under the nozzle.  This cleaning procedure draws the slurry
effluent from the pad pores into the region of lower pressure (P1).
The pad is conditioned with very little pad erosion.