Appeal No.2003-2001
Application No. 09/345,173
polysilicon, the basis for the combination asserted by the
examiner. As taught by Cher, the breakthrough etch is one of
four etching steps used in Cher’s dry etching process that
allegedly avoids undercutting and foot formation problems in
forming a polysilicon gate. The examiner has not referred us to
any disclosure in Chung that suggests the HF dip thereof does not
adequately remove the thin oxide from the polysilicon surface for
facilitating subsequent wet etching therein in their disclosed
field oxide regions and pad oxide region formation process.
While Cher (column 5, line 63 through column 6, line 1)
refers to an HF dip for removing sidewall deposits after the four
step etching procedure and resist stripping, the examiner has not
fairly explained how that disclosed HF dip step, occurring after
the four step etching operation and subsequent resist stripping
of Cher, would have suggested the proposed modification of
Chung’s process.
Nor has the examiner convincingly explained how Chen, the
alleged admitted prior art, and/or Vogel, as additionally applied
in the other rejections for allegedly rendering obvious other
features associated with the separately rejected claims, would
have suggested modifying Chung’s method to include the descumming
and breakthrough etch steps. Concerning appealed independent
claim 19 and the claims depending thereon, we note that, like
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