Appeal No. 2004-1231
Application 09/481,224
fabrication of semiconductor devices on the wafer.” Appellants
schematically illustrate a typical CMP apparatus in Figs. 1A and
1B. See Appellants’ specification, page 3, lines 4 and 5. In
addition, Appellants show another prior art CMP head in Fig. 1C.
Appellants further explain that the polishing pad in a CMP process
is rapidly deteriorated due to an effect known as “pad-glazing.”
Appellants’ specification, page 6, second paragraph. To remedy the
pad glazing effect, numerous techniques of pad conditioning or
scrubbing have been proposed to regenerate and thereby, restore the
pad surface. The pad conditioning process can be carried out
either during a polishing process, i.e., known as concurrent
conditioning, or after a polishing process. The conventional
apparatus of a conditioning disc is frequently not effective in
conditioning a pad surface because the diamond particles on the
surface of the conditioning disc may become lost, loosen, or
flattened. A method for preventing wafer surfaces from being
scratched by loose diamond particles that have been dislodged from
a conditioning disc is to pre-condition the conditioning disc.
Appellants’ specification, pages 7 and 8. Traditionally, this is
done in a CMP apparatus prior to the start of wafer polishing.
However, the pre-conditioning process takes at least 30 minutes of
fabrication time away from the CMP apparatus, thus, reduces the
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