Appeal No. 1999-2115
Application No. 08/724,574
art would have been motivated to make this substitution to the
process of Yu et al. because of the teaching of Rao et al. that
glass reflowing smooths [sic, smoothes] the profile of the glass
and leads to higher production yields." (Id.)
The problem with the examiner's analysis, however, is that
Yu '843 obtains a flat surface without the need for reflowing
any dielectric layer. As we discussed above, Yu' 843 teaches
that a flat surface is obtained by modifying the polishing rate
of selected areas. Furthermore, Rao is directed to a method
unrelated to a CMP process as described in Yu '843.
Specifically, Rao describes controlling the profile of an
interlevel dielectric prior to a reflowing step. (Column 2,
lines 42-45.) According to Rao, the interlevel dielectric is
deposited to a thickness significantly greater than needed, and
then etched back to the desired thickness. (Column 2, lines 45-
47.) The reflowing step in Rao is said to profile the contact
hole sidewalls and smooth out the profile of the dielectric
interlevel over a patterned stack 24 as shown in Figure 2.
Here, the examiner has not pointed to any disclosure in Rao
even hinting that the reflowing step can be used in lieu of the
process steps described in Yu '843 for the purpose of
eliminating scratches following the CMP process, much less any
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