Appeal No. 2004-0216
Application No. 09/460,112
cleaning solution and causes a contamination problem which
results in high defect rates. Accordingly, appellants remove the
SiON layer before cleaning to prevent the contamination.
Appealed claims 1-14 stand rejected under 35 U.S.C. § 103 as
being unpatentable over Wu in view of Cheng, Fulford and Chau.
We have thoroughly reviewed the respective positions
advanced by appellants and the examiner. In so doing, we find
that the examiner has failed to establish a prima facie case of
obviousness for the claimed subject matter. Accordingly, we will
not sustain the examiner's rejection.
The examiner appreciates that Wu, in forming an STI, does
not disclose the use of an SiON layer. According to the
examiner, it would have been obvious for one of ordinary skill in
the art to use the SiON layer of Cheng as the oxide layer in Wu
formed on the nitride layer. As for removing the SiON layer
before cleaning the substrate, the examiner maintains that "Chau
discloses a method in which the wafer is cleaned in the absence
of a silicon oxynitride layer" (page 7 of Answer, third
paragraph). Appellants, on the other hand, counter that Chau
teaches cleaning the substrate while the remaining oxynitride
layer (106) is still intact on the substrate and, therefore, Chau
teaches away from the claimed invention (page 12 of Brief, second
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