Appeal No. 1997-0548
Application 08/345,290
(“softbake”) and high temperature PEB taught by Brunsvold can be combined with the high temperature
prebake and low temperature PEB taught by Schlegel for the respective resists.
Appellants submit (principal brief, pages 7 and 9-10) that these two types of polymers are
different and, in this respect, point to, inter alia, the teaching in Brunsvold that vinyl polymers form
“resist structures that can withstand high temperatures without experiencing autodecomposition or
undergoing additional stabilization as in Deep UV hardening of Novolak resists” (page 357), which
arguments and disclosure is not addressed by the examiner. Both appellants and the examiner discuss
the teachings of section “E” of Schlegel (pages 284-285), with appellants also pointing to other
teachings in that reference. We find that in section “E” of Schlegel, the amount of solvent retained in
films after “identical prebaking conditions” at “80°C for 10 minutes” formed from “Polyvinylphenol
(resin M)” as well as from two novolak resins is discussed with respect to Schlegel Fig. 13, wherein it is
disclosed that the film formed with the former resin had a “higher content of solvent” (id.). While
Schlegel does state that “(i)n all cases, it is imperative to apply a prebaking near the glass transition
temperature” (page 285), we find no disclosure in this reference that the film formed with the vinyl
polymer was prebaked near its glass transition temperature or that the film that was prebaked at “80°C
for 10 minutes” was imaged and subjected to a PEB. Thus, on this record, we find that one of ordinary
skill in this art would have reasonably inferred from Schlegel that the teachings with respect to the
performance of the polyvinyl resist ended with the finding that “it is easier to remove solvent from
polymer films with lower glass transition temperature” from which Schlegel concludes that “it is not
necessarily advantageous to use a resist with high glass transition temperature” (page 285). Indeed, in
the absence of the disclosure of a complete imaging process, including a PEB for a polyvinyl resist in
Schlegel, there is little support for the examiner’s contention that the disclosure in the reference that, in
the absence of a prebake “near the glass transition temperature of the resist, . . . the high acid mobility
due to solvent traces would degrade the resolution of the resist” (page 285) applies to the vinyl polymer
resists. Thus, on this record, the prebake to which the film formed from “Polyvinylphenol (resin M)”
was subjected by Schlegel appears to correspond to the “softbake” employed with similar resin by
Brunsvold.
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