Ex Parte M

Board of Patent Appeals and Interferences

Jun 15, 2007

10997715 (B.P.A.I. Jun. 15, 2007)

The opinion in support of the decision being entered today
is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte HICHEN M’SAAD
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Appeal 2007-1312
Application 10/997,715
Technology Center 1700
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Decided: June 15, 2007
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Before EDWARD C. KIMLIN, BRADLEY R. GARRIS, and
CHARLES F. WARREN, Administrative Patent Judges.

KIMLIN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-18, 20, and 29.
Claims 1, 20, and 29 are illustrative:
1. A method for forming an optical waveguide on a substrate in a
process chamber, the method comprising:
depositing an undercladding layer over the substrate;
forming a plurality of separated optical cores over the undercladding
layer, the plurality of optical cores defining a sequence of gaps;

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depositing a first uppercladding layer over the plurality of cores and
within the gaps with a high-density plasma process having a deposition-
sputter ratio between 3:1 and 10:1 to partially fill the gaps, wherein the
deposition-sputter ratio is defined as the ratio of a sum of a net deposition
rate and a blanket sputtering rate to the blanket sputtering rate for the high-
density plasma process; and
depositing a second uppercladding layer over the first uppercladding
layer with a PECVD process to completely fill the gaps.
20. The method recited in claim 1 wherein the first uppercladding
layer has a refractive index between about 1.4443 and 1.4473 at a
wavelength of 1550 nm.
29. The method recited in claim 1 wherein the first uppercladding
layer fills the gaps to approximately 75% of a height of the cores and the
second uppercladding layer fills a remainder of the gaps.
The Examiner relies upon the following references as evidence of
obviousness:
Schneider US 4,557,561 Dec. 10, 1985
Imoto US 4,856,859 Aug. 15, 1989
Dragone US 5,136,671 Aug. 4, 1992
Liu US 6,117,345 Sep. 12, 2000
Narita US 6,122,934 Sep. 26, 2000
Bazylenko US 6,154,582 Nov. 28, 2000
Rossman US 6,194,038 B1 Feb. 27, 2001
Shieh US 6,204,200 B1 Mar. 20, 2001
Ngai US 6,451,686 B1 Sep. 17, 2002
Zhong US 6,705,124 B2 Mar. 16, 2004
Official Notice, Office Action of Jan. 28, 2005 (bottom of page 6)
Appellant’s claimed invention is directed to a method for forming an
optical waveguide on a substrate in a process chamber wherein a plurality of
separated optical cores are formed over an underclading layer that is
deposited upon the substrate. The optical cores define a sequence of gaps
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between them and a first upper cladding layer is deposited within the gaps
with a high-density plasma process (HDPCVD). The first upper cladding
layer partially fills the gaps and a second upper cladding layer is deposited
over the first upper cladding layer with a plasma-enhanced chemical vapor
deposition process (PECVD). The HDPCVD process for depositing the first
uppercladding layer has a deposition-sputter ratio between 3:1 and 10:1.
As acknowledged by Appellant, the present application is related to
U.S. Application 10/020,461, which is also presently on appeal before us for
decision (Appeal 2007-1851). The appealed claims of both the present
application and the related application recite the formation of a plurality of
separated optical cores over an undercladding layer having gaps formed
between the cores.
The appealed claims stand rejected under 35 U.S.C. § 103(a) as
follows:
(a) claims 1-7, 13-15, 18, 20, and 29 over Bazylenko in view of
Dragone, Liu, and Shieh;
(b) claim 8 over Bazylenko in view of Dragone, Liu, Shieh, and Ngai;
(c) claims 9-11 over Bazylenko in view of Dragone, Liu, Shieh,
Imoto, and Zhong;
(d) claim 12 over Bazylenko in view of Dragone, Shieh, Liu, Zhong,
Imoto, and Schneider;
(e) claim 16 over Bazylenko in view of Dragone, Liu, Shieh, and
Rossman; and
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(f) claim 17 over Bazylenko in view of Dragone, Shieh, Liu,
Rossmann, and Narita.
With the exception of claims 20 and 29, Appellant does not set forth
an argument that is reasonably specific to particular claims on appeal.
Accordingly, with the noted exceptions, all the appealed claims stand or fall
together with claim 1. Also, with the exception of the rejections of claims
20 and 29, we will limit our consideration to the Examiner’s rejection of
claim 1.
We have thoroughly reviewed each of Appellant’s arguments for
patentability. However, we fully concur with the Examiner that the claimed
subject matter would have been obvious to one of ordinary skill in the art
within the meaning of § 103 in view of the applied prior art. Accordingly,
we will sustain the Examiner’s rejections for essentially those reasons
expressed in the Answer, and we add the following primarily for emphasis.
For the reasons discussed in our Decision involving the related appeal
(Appeal 2007-1851), we find that the applied prior art establishes the
obviousness of forming an optical waveguide by depositing an
undercladding layer over a substrate, forming a plurality of separated optical
cores over the undercladding layer which define a sequence of gaps between
the cores, and depositing an uppercladding layer within the gaps and over
the plurality of cores. Also, Appellant has not contested the Examiner’s
legal conclusion that it would have been obvious for one of ordinary skill in
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the art to perform the HDPCVD process of Bazylenko with a deposition-
sputter ratio within the claimed range, based on the teachings of Liu and
Shieh (see Answer 7, first two paras.).
A principal argument advanced by Appellant is that the cited prior art,
particularly Liu, does not evidence the obviousness of using an HDPCVD
process to partially fill the gaps between the cores and then use a PECVD
process to completely fill the gaps with the uppercladding layer. Appellant
emphasizes the disclosure of Liu that the HDPCVD process “is performed
until the gap 36 is substantially filled. . . .” (col. 9, ll. 6-7). Appellant
contends that the Liu disclosure teaches away from the claimed step of only
partially filling the gaps with the HDPCVD process.
We are not persuaded by Appellant’s argument. First, we concur with
the Examiner that there is no meaningful, patentable distinction between the
claimed step of partially filling the gaps and Liu’s substantially filling the
gaps. The appealed claims fail to define any percentage value related to
partially filling. Therefore, the appealed claims broadly encompass methods
wherein less than 100% of the gaps are filled, e.g., 99%, 98%, etc. On the
other hand, it is reasonable to conclude that the substantial filling of Liu is
also less than 100%, e.g., 99%, 98%, etc. Consequently, we find the
Examiner’s reasoning to be sound that there is no patentable distinction
between Appellant’s partial filling and Liu’s substantial filling.
In addition, it is clear from Liu’s figure 4 that the first uppercladding
layer 38 does not completely fill the gap between the electrical components
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which are defined by upper elements 28 and 38. The gaps are defined by
more than just wiring 24.
Moreover, even if Liu were interpreted as completely filling the gaps
with the HDPCVD process, we completely agree with the Examiner that it
would have been a matter of obviousness for one of ordinary skill in the art
to use the HDPCVD process to only partially fill the gaps and use the
PECVD process to complete the deposition of the uppercladding layer. As
explained by the Examiner, Liu discloses that the PECVD process affords a
higher speed of deposition than is typical of HDPCVD processes. As a
result, one of ordinary skill in the art would have understood that a balance
can be effected between the benefits achieved by the slower HDPCVD
process and the faster PECVD process. Liu discloses that the HDPCVD
process deposits “a dielectric layer having superior density, moisture
resistance and planarization properties as compared to conventional CVD
dielectric layers” (sentence bridging col. 4-5), while also producing a void-
free gap filling. Liu also discloses that “[a]nother advantage of the use of
HDPCVD to deposit intermetal dielectrics is that it is generally not
necessary to perform subsequent high temperature densification steps to
densify the deposited dielectric material, which may sometimes be required
to densify oxide layers deposited using conventional CVD and other
techniques” (col. 6, ll. 5-10). Manifestly, it would have been obvious for
one of ordinary skill in the art to perform a cost-benefit analysis in
determining the amount of uppercladding layer to be deposited by the
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HDPCVD and PECVD processes. Appellant has not argued, let alone
established with requisite objective evidence, that the benefits espoused by
Liu for HDPCVD deposition are not sacrificed when using it to only
partially fill the gaps.
We are not persuaded by Appellant’s argument that “Liu is drawn
from the electronic-device arts rather than the optical-device arts” (principal
Br. 8, last sentence). In our view, since both Appellant and Liu are directed
to filling gaps with a high aspect ratio, one of ordinary skill in the art would
have had a reasonable expectation that the HDPCVD process of Liu would
be as effective in filling the gaps in an optical device as in an electronic
device.
Regarding the separately argued claim 20 recitation of the
uppercladding layer having a refractive index between “about 1.4443 and
1.4473,” we agree with the Examiner that the “about” language fails to
distinguish over the refractive index of 1.45 disclosed by Bazylenko. It is
well settled that the claim term “about” allows for some variation from the
stated value. In re De Vaney, 185 F.2d 679, 683, 88 USPQ 97, 101 (CCPA
1950); In re Ayers, 154 F.2d 182, 185, 69 USPQ 109, 112 (CCPA 1946).
Moreover, we find that it would have been a matter of obviousness for one
of ordinary skill in the art to determine the optimum refractive index for the
uppercladding layer which correspond to the objectives of a specific optical
device.
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As for the separately argued recitation of claim 29 that the first
uppercladding layer fills the gaps to approximately 75% of the height of the
cores, we are convinced, for the reasons set forth above, that it would have
been obvious for one of ordinary skill in the art to conduct a typical cost-
benefit analysis to determine how much of the gaps are filled by the
HDPCVD process.
As a final point, we note that Appellant bases no argument upon
objective evidence of nonobviousness, such as unexpected results.
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) (2006).
AFFIRMED

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