Browse Prior Art Database

Pad Conditioning to Control Radial Uniformity of Mechanical Polishing

IP.com Disclosure Number: IPCOM000119746D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 89K

Publishing Venue

IBM

Related People

Cote, WJ: AUTHOR

Abstract

Pressure is varied on a polishing pad conditioning bar to control polishing removal rate. Center to edge polishing removal rate of surface material on a semiconductor wafer is made equal by appropriate pressure variation along the pad conditioning bar.

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This is the abbreviated version, containing approximately 93% of the total text.

Pad Conditioning to Control Radial Uniformity of Mechanical Polishing

      Pressure is varied on a polishing pad conditioning bar to
control polishing removal rate.  Center to edge polishing removal
rate of surface material on a semiconductor wafer is made equal by
appropriate pressure variation along the pad conditioning bar.

      Referring to the figure, polishing pad 2, having a slurry of
polishing particles within its nap, is attached to polishing table 4
which is rotated in a counter-clockwise direction.  Wafer 6 is
disposed above pad 2 and is brought into face-down pressure contact
with polishing pad 2 and rotated in a clockwise direction.  Pad
conditioning bar 8 is disposed above pad 2 and is brought into
contact with pad 2 with pressure variable at points A and B.  Bar 8
has a rough surface which raises the nap of pad 2, thereby increasing
the polishing removal rate of material on the surface of wafer 6.  To
increase the polishing rate of removal near the center of wafer 6
more than at its edge, pressure between bar 8 and pad 2 is increased
at point A.

      To maximize control of polishing rate of removal by pressure on
pad conditioning bar 8, relatively low pressure is applied between
wafer 6 and pad 2, relatively low concentation of slurry material,
relatively low temperature, low table speed, and a hard polishing pad
is used.

      To minimize wear and resulting decreased effectiveness of the
rough surface of bar 8, that surface is made...