Appeal No. 2001-1662
Application No. 09/048,208
demonstrated how continuation of the step of etching the
metalization layer in any way discloses or suggest the claimed
two step process wherein the portion of the metal layer remaining
in the narrow spaces from the first etching step is removed in a
subsequent selective etching step.
Similarly, the examiner has not identified any teaching or
suggestion in Abraham which requires the two step etch and
selective etch for removal or the barrier metal layer.
We further note that claim 1 requires that the step of
etching the barrier metal layer does not commence until after all
of the metal layer has been removed from the narrow spaces as
required in the prior step. In particular, we note that the use
of the word "thereafter" clearly signals a subsequent step.
Similarly, the claims require that over etching the insulating
layer does not commence until after the step of selectively
etching away all of the barrier metal layer remaining in the
narrow spaces, as again indicated by use of the word
"thereafter." In fact, Abraham specifically states that
"[a]lthough the second chemistry may [sic, be] extended to etch
through the barrier layer, the third chemistry employed in step
405 may be better suited to etch through the remaining
metalization layer and into an underlying layer." Column 9,
77
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