Appeal No. 2002-0897
Application 09/303,020
The appellants argue (reply brief, page 3):
Roy et al. teach “[t]he HF spray after scrubbing
removes metal contaminants to below detection limits”
(Roy et al., col. 6, lines 30-32)(emphasis added). If
anything, Roy et al. suggest[s] on its face that the
brush scrubbing and megasonic cleaning (col. 5,
lines 22-36) fail to accomplish the task of cleaning
the surface of the wafer and require a HF spray to
remove the residuals (col. 6, lines 30-32). Appellants
respectfully submit that one skilled in the art would
conclude from Roy et al. that since brush scrubbing is
not able to remove all residuals from a flat surface
(col. 6, lines 30-32), it would not effectively clean
an open cavity in a semiconductor wafer.
Actually, what Roy discloses is that “[t]he HF spray after
scrubbing removes most of the metal contaminants to below
detection limits” (col. 6, lines 30-32). Thus, Roy indicates
that some residuals remain even after the HF spray. Roy teaches
that each of the steps contributes to the removal of unwanted
particles from the wafer surface (col. 6, lines 35-37). One of
ordinary skill in the art, therefore, would not have been
discouraged by Roy from using brush scrubbing to remove particles
from a cavity-containing surface.2
2 Hence, we are not persuaded by the appellants’ argument
that one of ordinary skill in the art would have been led by Doan
and Roy to use only variants of the HF process and not brushing
to remove particles from an open portion of a cavity in a
semiconductor wafer (reply brief, page 3).
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