Appeal No. 1998-2620
Application No. 08/512,033
claim 1 on appeal in three ways: (1) controlling a bypass
valve to prevent by-products from feeding back into the main
reaction chamber; (2) heating the section of the pumping
system closest to the reaction chamber; and (3) performing the
claimed steps in sequence (Answer, page 4). The examiner
applies JP ‘775 to show an “operable bypass valve” in an
exhaust line of a conventional LPCVD (low pressure CVD)
process (Answer, page 4). The examiner finds that “the bypass
valve has long been used in exhaust lines of CVD apparatus for
reducing contamination in CVD chambers as evidenced by JP02-
107,775.” Id. The examiner applies Ozaki for the teaching to
heat the section of the pumping system that is closest to a
CVD chamber because “it has been recognized in the CVD art
that vacuum line can be heated in order to eliminate
condensation of possible impurities on internal walls of the
line.” Answer, paragraph bridging pages 4-5. Regarding
difference (3) between the prior art sequence of steps and the
claimed sequence of steps, the examiner concludes that
“optimization of opening and closing by-pass valves during CVD
processes in order to obtain the optimized effect would have
been within the expected skill to a routineer in the CVD art.”
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