Appeal No. 96-0386
Application No. 08/270,082
effect on anisotropy and selectivity of various mixtures of
SF used in the reactive ion etching technique of dry etching.
6
Appellants assert that nowhere in Pinto is there any
disclosure that dry etching with SF or mixtures of SF would6 6
cause less damage relative to any other dry etch chemical.
After careful review of the reference to Pinto, we are in
agreement with Appellants. However, even assuming,
arguendo, that Pinto provides support for the notion that the
use of SF as a dry etch chemical prevents substrate damage
6
in comparison with other chemicals, it is our view that it
would not have been prima facie obvious to combine Suehiro and
Pinto since we agree with Appellants (Brief, page 6) that
Suehiro "teaches away" from the claimed invention. Instead of
choosing a particular chemical to dry etch the silicon nitride
layer to prevent damage to the substrate, Suehiro's solution
to the problem is to add an additional protective layer of
dielectric over the substrate. Accordingly, the skilled
artisan would not have looked to the disclosure of Pinto to
select a particular dry etch chemical to prevent damage in
Suehiro when Suehiro's disclosed solution to the problem, i.e.
the addition of a protective dielectric layer over the
8
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 Next
Last modified: November 3, 2007