Ex Parte Benz

Board of Patent Appeals and Interferences

Nov 19, 2008

10707908 (B.P.A.I. Nov. 19, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte JASON M. BENZ
____________

Appeal 2008-4930
Application 10/707,908
Technology Center 1700
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Decided: November 19, 2008
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Before EDWARD C. KIMLIN, TERRY J. OWENS, and
PETER F. KRATZ, Administrative Patent Judges.

KIMLIN, Administrative Patent Judge.

DECISION ON APPEAL

This is an appeal from the final rejection of claims 1, 3-5, 8, 10-12,
15, 17, 18, and 21-26. Claim 1 is illustrative:
1. A method of forming a phase shift mask, said method comprising:

forming an opaque layer on a transparent substrate;

Appeal 2008-4930
Application 10/707,908

performing a first patterning of said opaque layer to expose a first
region of said transparent substrate, wherein said first region comprises an
uninterrupted rectangular surface;

etching said first region of said transparent substrate to create a phase
shift region within said transparent substrate; and

performing additional patterning of said opaque layer to expose a
second region of said transparent substrate, such that said second region
comprises a similar shape and size as said first region, wherein said second
region is adjacent said first region, and wherein said additional patterning
process enlarges an opening formed in said first patterning process.

The Examiner relies upon the following references as evidence of
obviousness:
Dao US 5,302,477 Apr. 12, 1994
Tzu US 5,888,678 Mar. 30, 1999
Levenson US 6,251,549 B1 Jun. 26, 2001
Rolfson US 6,395,432 B1 May 28, 2002
Schroeder US 6,605,396 B2 Aug. 12, 2003
Sandstrom US 6,605,816 B2 Aug. 12, 2003

Appellant's Admitted Prior Art Jan. 23, 2004

Appellant's claimed invention is directed to a method of forming a
phase shift mask. The method entails patterning an opaque layer on a
transparent substrate to form a first region of the substrate of an
uninterrupted rectangular surface. The first region is etched to create a
phase shift region within the transparent substrate, and a second region of
the transparent substrate is exposed by additional patterning of the opaque
later. The second region comprises a similar shape and size as the first
region and is adjacent thereto.

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Application 10/707,908

Appealed claims 21-23 stand finally rejected under 35 U.S.C. § 112,
first paragraph. The appealed claims also stand finally rejected under
35 U.S.C. § 103(a) as follows:
(a) claims 1, 3-5, 15, 17, 18, 24, and 26 over Dao in view of
Schroeder,
(b) claims 1, 3-5, 15, 17, 18, 24, and 26 over Dao in view of
Schroeder and either Levenson, Rolfson or the Admitted Prior Art,
(c) claims 8, 10-12, and 25 over Dao in view of Schroeder and Tzu,
(d) claims 8, 10-12, and 25 over Dao in view of Schroeder, Tzu, and
either Levenson, Rolfson or the Admitted Prior Art,
(e) claims 21 and 23 over Dao in view of Schroeder and either
Levenson, Rolfson or the Admitted Prior Art further in view of Sandstrom,
and,
(f) claim 22 over Dao in view of Schroeder, Tzu and either Levenson,
Rolfson or the Admitted Prior Art further in view of Sanstrom.
We have carefully considered each of the arguments advanced by
Appellant. However, we are in complete agreement with the Examiner's
reasoned analysis and application of the prior art, as well as his cogent and
thorough disposition of the arguments raised by Appellant. Accordingly, we
will adopt the Examiner's reasoning as our own in sustaining the rejections
of record, and we add the following for emphasis only.
At the outset, we will summarily affirm the Examiner's rejection of
claims 21-23 under 35 U.S.C. § 112, first paragraph, since Appellant has not
contested this rejection.
Concerning the § 103 rejections, there is no dispute that Dao, the
primary reference in all of the rejections, discloses a method of forming a
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Application 10/707,908

phase shift mask comprising the claimed steps of forming an opaque layer
on a transparent substrate, exposing a first region of the transparent substrate
which is then etched to form a first opening, removing a second portion of
the opaque layer to expose a second region of the transparent substrate such
that the first region is enlarged (see reference Fig. 4A).
A principal argument advanced by Appellant is that "because Dao
teaches regions comprising a rectangular ring having an intervening
structure in the middle thereof, Dao teaches away from the claimed features
'wherein said first region comprises an uninterrupted rectangular surface . . .
and . . . said second region comprises a similar shape and size as said first
region'" (Br. 17, first para). However, in the words of the Examiner, the
rejection "is not based on this particular rim PSM example of Dao et al.
alone, but rather on other exemplary teachings of Dao et al in combination
with Schroeder et al." (Ans., sentence bridging pages 18-19). As
emphasized by the Examiner, Dao expressly discloses that "[t]he methods of
the present invention are not limited to the specific rim or outrigger phase-
shifting opening patterns shown in FIGS. 4A and 5A-E. The present
invention may be used for any patterns having phase-shifting elements
which are spaced in close proximity to other such patterns. For example
FIG. 6 . . ." (col. 8, ll. 1- et seq.). PS region 42b of Dao is directly adjacent
non-PS region 45a and have similar shapes and sizes (See Fig. 6).
Also, we are in complete agreement with the Examiner that
Appellant's broad claim language "comprises an uninterrupted rectangular
surface," encompasses Dao's Fig. 4A wherein first region 24 includes
rectangular area 23, which "is itself an uninterrupted rectangular surface"
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(Ans. 21, second para.). Hence, region 24 of Dao meets the claim recitation
of comprising an uninterrupted rectangular surface, namely, surface area 23.
As for Appellant's argument that region 460 of Schroeder's FIGS. 6a
and 6b "does not have similar size and shape as the region 458" (Br. 19, last
para.), we observe that the claim language "similar shape and size" is
broadly drafted and inexact such that it does not serve to distinguish over the
referenced elements of Schroeder which, in our view, may be fairly
considered similar. Moreover, as noted by the Examiner, Fig. 6a of
Schroeder depicts regions 456 and 458 to have the same or similar size, as
well as regions 454 and 460.
Regarding Appellant's argument that Levenson and Rolfson teach
simultaneous formation of the first and second regions, the Examiner
properly explains that Dao is cited for the obviousness of sequential, non-
simultaneous formation of the first and second regions. Levenson and
Rolfson are cited by the Examiner as evidence for the obviousness of having
similarly shaped and sized first and second regions wherein the first region
has an uninterrupted rectangular surface that lacks an intervening structure.
In addition, we find that the appealed claims do not preclude simultaneous
formation of the first and second regions inasmuch as the claimed step of
"performing additional patterning" is sufficiently broad to embrace the
additional patterning occurring during the first patterning step.
Concerning the Admitted Prior Art cited by the Examiner, Appellant's
Specification states the following at paragraph [0018]:
Figures 1A-3B illustrate a methodology that is utilized to
create a phase shift mask. This methodology is not
necessarily well known; however, the invention is an
improvement on this methodology.
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Manifestly, it is not clear what constitutes the Admitted Prior Art in terms of
what was known and what was well known and, unfortunately, Appellant
has done nothing to clarify the record with respect to the nature of the prior
art.
Appellant also maintains that since Tzu teaches that the phase shifting
material 26 remains over the substrate 20 and the substrate remains
unexposed, the reference "teaches against the claimed feature of performing
a first patterning of said opaque layers to expose a first region of said
transparent substrate . . . " (Br. 38, second para.). However, as set forth by
the Examiner, Tzu is cited for teaching that forming additional third binary
mask pattern regions that are devoid of PS features on the same transparent
mask substrate having PS features increases throughput and decreases cost
in the fabrication of integrated circuit wafers" (Ans. 37, penultimate para.).
Appellant also contends that "because Sandstrom teaches exposing the
region 327 . . . by not patterning the layer 302, Sandstrom teaches away
from the claimed invention" (Br. 62, second para.). However, the Examiner
has cited Sandstrom as evidence that "one of ordinary skill in the art would
have recognized that improving the uniformity of a PSM by further etching
to attach the substrate during additional patterning to make the PSM (as
taught by Sandstrom) would be reasonably expected to be just as
advantageous for improving the uniformity in the combined method of
making the PSM taught by the other references" (Ans. 46, second para.).
As a final point, we note that Appellant bases no argument upon
objective evidence of nonobviousness, such as unexpected results, which
would serve to rebut the inference of obviousness established by the applied
prior art.
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In conclusion, based on the foregoing and the reasons well stated by
the Examiner, the Examiner's decision rejecting the appealed claims is
affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv)(effective
Sept. 13, 2004).
AFFIRMED

cam

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