Appeal No. 2003-0230
Application No. 09/624,025
structure with improved reliability.
The appellants, on the other hand, urge that the nitride
spacers of Sheng cannot be substituted into the teaching of
Gardner. The spacers, they contend, are temporary, and it is
important to Sheng that the spacers be a different material from
the oxide fill layer. (Appeal Brief, page 6, lines 2-21).
In response, the examiner states that although he agrees that
the sidewall spacers are removed, Sheng was used to show that it
was known to use nitride spacers and that the substitution of
nitride for oxide is obvious. (Examiner’s Answer, page 11, lines
16-19).
We agree with the appellants. First, we note that the
examiner has failed to provide any motivation for making the
switch of nitride for oxide. Sheng discloses that it is known to
use a nitride for a temporary sidewall spacer, which spacer is
totally removed by an isotropic hot acid etching process. (Column
4, lines 26-28). Further, the nitride layer is said to be
different from the oxide layer, in that the oxide layer is used as
an etching stop layer for the etching process (Id., lines 28-32).
The examiner has not shown why it would be desirable to replace
the oxide with the nitride.
Further, if the examiner’s position is that Sheng establishes
that they are equivalent or interchangeable, we disagree. Sheng
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