Ex parte Hsiao

Board of Patent Appeals and Interferences

May 29, 2002

09116612 (B.P.A.I. May. 29, 2002)

-1-
The opinion in support of the decision being entered
today was not written for publication in a law
journal and is not binding precedent of the Board.
Paper No. 12
UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES

Ex parte YUNG-KUAN HSIAO

Appeal No. 2001-0228
Application No. 09/116,612

ON BRIEF

Before KIMLIN, OWENS and JEFFREY T. SMITH, Administrative
Patent Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-
15, all the claims in the present application. Claim 1 is
illustrative:
1. A method for forming a patterned composite stack layer
within a microelectronics fabrication comprising:
providing a substrate;
forming over the substrate a blanket first silicon layer;
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Application No. 09/116,612
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forming upon the blanket first silicon layer a blanket
silicon containing dielectric layer;
forming upon the blanket silicon containing dielectric
layer a blanket second silicon layer;
forming upon the blanket second silicon layer a blanket
organic polymer anti-reflective coating (ARC) layer;
forming upon the blanket organic polymer anti-reflective
coating (ARC) layer a patterned photoresist layer; and
etching sequentially while employing the patterned
photoresist layer as a photoresist etch mask layer the blanket
organic polymer anti-reflective coating (ARC) layer, the
blanket second silicon layer, the blanket silicon containing
dielectric layer and the blanket first silicon layer to form a
patterned composite stack layer comprising a patterned second
silicon layer coextensive with a patterned silicon containing
dielectric layer in turn coextensive with a patterned first
silicon layer, where the sequential etching is undertaken
employing a single plasma etch method employing an etchant gas
composition which upon plasma activation forms a chlorine
containing etchant species.
The examiner relies upon the following references as
evidence of obviousness:
Kolar et al. (Kolar) 5,162,259 Nov. 10, 1992
Azuma et al. (Azuma) 5,759,746 Jun. 02, 1998
Huang et al. (Huang) 5,837,428 Nov. 17, 1998
According to appellant, "[t]he present invention provides
a method for efficiently and with attenuated microloading
effect forming within a microelectronics fabrication a
patterned composite silicon/dielectric/silicon stack layer"
(page 3 of Brief, penultimate paragraph). The claimed method
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employs an organic polymer anti-reflective coating under the
photoresist layer and "a single plasma etch method employing
an etchant gas composition which upon plasma activation forms
a chlorine containing etchant species" (claim 1).
Appealed claims 1-15 stand rejected under 35 U.S.C. § 103
as being unpatentable over Huang in view of Kolar.
Upon careful consideration of the opposing arguments
presented on appeal, we concur with appellant that the
examiner has not established a prima facie case of obviousness
for the claimed method. Accordingly, we will reverse the
examiner's rejection.
The examiner recognizes that Huang, the primary
reference, "differs from the instant claimed invention by
using three sequential etching steps instead of [a] single
sequential etching step" (page 5 of Answer, sixth paragraph).
However, the examiner relies upon Kolar for "performing a
single sequential etching step to etch all layers of the stack
layers using chlorine based reactive etch gases (Col 3, lines
17-45)" (page 5 of Answer, penultimate paragraph). The
examiner explains that:
Although, Kolar does not clearly recite
sequentially etching of the tri-layer using a single
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Application No. 09/116,612
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plasma etch method employing an etchant gas
composition which upon plasma activation forms a
chlorine containing species, Kolar does specifically
discloses [sic, disclose] that the sequential etch
of the tri-layer can be carried out using a plasma
etching process to etch all layers (col 3, lines 17-
18) [page 6 of Answer, last paragraph].
Our reading of Kolar does not correspond to the
examiner's understanding. Specifically, Kolar discloses that
"[t]he sequential etch can be carried out using a plasma
etching process to etch all layers, or alternatively, the
etching can be carried out by a combination of plasma etching
and liquid chemical etching" (column 3, lines 17-22). In our
view, a reasonable interpretation of the Kolar disclosure is
that the operation can be carried out either by plasma
etching, alone, or in combination with liquid chemical
etching, but not that the plasma etching can be performed via
a single plasma etching step, as required by the appealed
claims. As recognized by the examiner, although Huang employs
only plasma etching, the operation entails three sequential
plasma etching steps. Hence, there is simply no teaching or
suggestion in either reference to perform the etching
operation with a single plasma etch method. In addition, we
also note that Kolar does not disclose etching a composite
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silicon/ dielectric/silicon stack layer as required by
appellant and disclosed by Huang.
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In conclusion, based on the foregoing, the examiner's
decision rejecting the appealed claims is reversed.
REVERSED
EDWARD C. KIMLIN )
Administrative Patent Judge )
)
)
)
)
TERRY J. OWENS ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
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)
)
JEFFREY T. SMITH )
Administrative Patent Judge )
ECK:clm
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Application No. 09/116,612
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George O. Saile
20 McIntosh Dr.
Poughkeepsie, NY 12603