Appeal No. 1998-2405
Application 08/351,093
a specific portion of a sample with a focused ion beam in an
atmosphere containing a tri- or tetracyclic aromatic compound
vapor, thereby polymerizing or carbonizing the organic
compound on the portion of the sample irradiated by the
scanned ion beam (page 3, lines 1-15; page 4, lines 22-31;
page 5, lines 24-27). Nakagawa teaches that this technique
has the benefit of forming patterns less than one micron wide
in a short time in a single step (page 7, lines 29-33).
Ozaki discloses a method for forming fine patterns by
irradiating a semiconductor substrate with an electron beam in
a hydrocarbon atmosphere containing at least methane and
ethane to form a film selectively on the irradiated portions
of the substrate, and etching exposed parts of the substrate
by reactive ion etching using the film as a mask (pages 6-7
and 9).
The examiner argues that because Ozaki’s method is
similar to that of Nakagawa, one of ordinary skill in the art
would have had a reasonable expectation of success in
substituting Nakagawa’s film formation technique for that of
Franke in order to provide a film which is resistant to ion
beam etching and which is formed using less steps, time and
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