Appeal No. 2004-0574
Serial No. 09/259,145
doped silicon thin film (103) and is formed on both sides of a
silicon substrate (101) (col. 6, lines 56-60). The gettering
layer is covered on both sides of the substrate with a protective
silicon nitride film (104) (col. 7, lines 27-31; figure 11).
Koike teaches that “[t]he silicon thin film to which an impurity
was added, and the silicon nitride film 104 are formed generally
by a reduced pressure CVD [chemical vapor deposition] method, and
therefore these films are deposited on the reverse surface of the
silicon substrate 101” (col. 6, line 65 - col. 7, line 2).
The examiner argues that Koike teaches that the silicon
nitride film unavoidably forms on the reverse surface of the
substrate, and that “[t]herefore, in view of this teaching of
Koike, the silicon nitride material formed in Tada, col. 6,
lines 30-31, will also form on the bottom surface of the
substrate” (answer, page 4).
Koike teaches that reduced pressure CVD forms his silicon
nitride film on both surfaces of the substrate. This apparently
occurs because in that method the substrates are held in a wafer
boat such that both substrate surfaces are exposed to the film-
forming gas.1 As of Tada’ filing date, however, it was known in
1 See Stanley Wolf and Richard N. Tauber, 1 Silicon
Processing for the VLSI Era 174-75 (Lattice Press 2000). A copy
of the cited portions of this reference is provided to the
appellants with this decision.
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