Ex Parte Schmitt et al

Board of Patent Appeals and Interferences

Jun 18, 2009

10642081 (B.P.A.I. Jun. 18, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte FRANCIMAR C. SCHMITT and HICHEM M’SAAD
____________

Appeal 2009-003534
Application 10/642,081
Technology Center 1700
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Decided:1 June 18, 2009
____________

Before TERRY J. OWENS, PETER F. KRATZ, and
JEFFREY B. ROBERTSON, Administrative Patent Judges.

ROBERTSON, Administrative Patent Judge.

DECISION ON APPEAL

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, begins to run from the Decided Date
shown on this page of the decision. The time period does not run from the
Mail Date (paper delivery) or Notification Date (electronic delivery).

Appeal 2009-003534
Application 10/642,081

STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
rejection of pending claims 1-20. (Appeal Brief filed September 4, 2007,
hereinafter “App. Br.,” 5). We have jurisdiction pursuant to 35 U.S.C. §
6(b).
We AFFIRM.
THE INVENTION
Appellants describe a method for depositing a low dielectric constant
film by delivering a gas mixture of one or more cyclic siloxanes and one or
more inert gases to a substrate in a chamber, where the ratio of a total flow
rate of the one or more cyclic organosiloxanes into the chamber to a total
flow rate of the one or more inert gases into the chamber is from about 0.10
to about 0.20. (Spec. para. [0007] and [0026]). Claim 1, reproduced below,
is representative of the subject matter on appeal.
1. A method for depositing a low dielectric constant film,
comprising:
delivering a gas mixture comprising:
one or more cyclic organosiloxanes; and
one or more inert gases to a substrate in a chamber,
wherein a ratio of a total flow rate of the one or more cyclic
organosiloxanes into the chamber to a total flow rate of the one
or more inert gases into the chamber is from about 0.10 to about
0.20; and
applying RF power to the gas mixture at conditions
sufficient to deposit a film on the substrate.

THE REJECTIONS
The prior art relied upon by the Examiner in rejecting the claims on
appeal is:
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Li US 6,358,839 B1 Mar. 19, 2002
Grill US 6,437,443 B1 Aug. 20, 2002
Lukas US 2004/0096593 A1 May 20, 2004
Abeles US 6,888,984 B2 May 3, 2005

The Examiner rejected claims 1-7 and 9-20 under 35 U.S.C. § 103(a)
as being unpatentable over Grill in view of Li and Abeles. The Examiner
rejected claim 8 as being unpatentable over Grill in view of Li and Abeles,
and further in view of Lukas.
The Examiner found that Grill discloses a method of depositing a low
dielectric constant film as recited in the present claims except for the relative
amount of inert gas. (Examiner’s Answer entered October 31, 2007,
hereinafter “Ans.,” 3). The Examiner found that Li teaches that it is
desirable to have a film under compressive stress and that Abeles teaches
that the stress in a film can be controlled by adjusting inert gas dilution.
(Id.). The Examiner concluded that it would have been obvious to adjust the
cyclic organosiloxane to inert gas ratio in Grill to control the stress of the
film. (Id.). The Examiner also determined that it would have been obvious
to one of ordinary skill in the art to determine the exact ratio through routine
experimentation depending on the desired stress of the deposited film. (Id.).
Appellants contend that in order to solve the problem of tensile stress,
Li does not change the method of depositing a dielectric film, but inserts a
layer of silicon nitride having a substantially compressive stress between the
low dielectric layer and the substrate. (App. Br. 10). Appellants argue that
Abeles does not teach low dielectric films. (App. Br. 11). Appellants
further contend that none of the references teaches or suggests controlling
the ratio of flow rates of cyclic organosiloxane to inert gas to the levels
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recited in the claims. (Id.). Appellants also argue that Grill does not enable
one of ordinary skill in the art to make a low dielectric constant film because
there is no direction as to how much precursor gas must be added to make a
low dielectric constant film. (App. Br. 12).

ISSUE
Have Appellants shown that the Examiner reversibly erred in
determining that it would have been obvious to one of ordinary skill in the
art to adjust the ratio of a total flow rate of one or more cyclic
organosiloxanes to a total flow rate of one or more inert gases in the gas
mixture disclosed in Grill, to from about 0.10 to about 0.20 as recited in the
appealed claims, in view of Li and Abeles?

FINDINGS OF FACT
The record supports the following findings of fact (FF) by a
preponderance of the evidence.
1. Appellants’ Specification states:
The flow rates described above may vary depending on the size
of the processing chamber used. The flow rates of the cyclic
organosiloxane and the one or more inert gases are chosen such
that the ratio of a flow of the cyclic organosiloxane into the
chamber to a total flow rate of the one or more inert gases is
between about 0.1 to about 0.2.
(Spec. para. [0026]).

2. Appellants’ Specification states that lower ratio of flow rate of
cyclic organosiloxane to the flow rate of inert carrier gas
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contributes to the compressive stress and the low tensile stress of
the examples. (Spec. para. [0062]).
3. Appellants’ Specification states that the chamber pressure of 2
Torr to about 10 Torr contributes to the dielectric constants of <
3.4 and the compressive or low tensile stress of the films. (Spec.
para. [0063]).
4. Grill discloses preparing a low dielectric constant film by
delivering an organosiloxane precursor to a reactor with an inert
carrier gas. (Col. 3, ll. 20-34).
5. Grill discloses that the low dielectric constant material is fabricated
by plasma enhanced chemical vapor deposition (PECVD). (Col. 1,
ll. 54-58; col. 6, ll. 30-59).
6. Grill discloses a gas mixture of 1, 2, 3, 5, 7-
tetramethylcyclotetrasiloxane (TMTCS) and helium delivered at a
flow rate of 30 sccm. (Col. 7, ll. 40-47).
7. Li states:
Inorganic low k dielectrics enjoy several
advantages over the organic variety, such as good
thermal conductivity suitability for production, but one
problem associated with them is that many of them, when
in thin film form are found to be in a state of high tensile
stress. This is the case, regardless of how they are
deposited. Because of this, low k inorganic films have a
tendency to delaminate, particularly near the edges of the
substrates where the restoring forces are the strongest.
(Col. 1, ll. 54-62).
8. Li discloses that depositing a layer using PECVD ensures desired
levels of compressive stress. (Col. 3, ll. 10-15).
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9. Abeles states:
PECVD processes are generally well suited for thick film
applications as a high deposition rate (~5 µm/hr) may be
obtained and stress in the film may be controlled over a wide
range, from tensile to compressive, by adjusting deposition
parameters such as pressure an inert gas dilution for example.
(Col. 5, ll. 10-17).

PRINCIPLES OF LAW
In KSR, the Supreme Court explained, “[w]hen a work is available in
one field of endeavor, design incentives and other market forces can prompt
variations of it, either in the same field or a different one. If a person of
ordinary skill can implement a predictable variation, §103 likely bars its
patentability.” KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 417 (2007).
In responding to a prima facie case of obviousness, one cannot show
nonobviousness by attacking references individually where the rejections are
based on combinations of references. In re Keller, 642 F.2d 413, 426
(CCPA 1981); In re Merck & Co., Inc., 800 F.2d 1091, 1097 (Fed. Cir.
1986).
The Federal Circuit has held that when the difference between a
claimed invention and the prior art is a claimed range; the applicant must
show that the range is critical through unexpected results rather than an
optimization of properties. In re Boesch, 617 F.2d 272, 276 (CCPA 1980);
In re Woodruff, 919 F.2d 1575, 1578 (Fed. Cir. 1990) (internal citations
omitted).

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ANALYSIS
Appellants have not presented separate arguments for the dependent
claims. Accordingly, we confine our discussion to appealed claim 1, which
contain claim limitations representative of the arguments made by
Appellants, and claims 2-7 and 9-20 stand or fall with claim 1 pursuant to 37
C.F.R. § 41.37(c)(1)(vii).2
We agree with the Examiner that Appellants’ arguments unduly focus
on each reference individually rather than the rejection as a whole.
Specifically, the Examiner does not rely on Li for inserting a SiN layer in
order to impart compressive stress. Rather, the Examiner cites Li for
recognizing that high tensile stress is a problem in low dielectric films
desposited by PECVD. (Ans. 3). The Examiner relies on Abeles for the
proposition that the stress in a PECVD film can be controlled by varying
pressure and inert gas dilution. (Id.). Thus, although Li discloses a different
solution for controlling the tensile stress of the film, there is no persuasive
evidence on the record that one of ordinary skill in the art would have been
discouraged from applying the method of Abeles as an alternative method
for controlling tensile stress of a PECVD film to the films of Grill.
We are also not persuaded by Appellants’ argument that because
Abeles fails to teach low dielectric layers, there is no indication that
controlling inert gas dilution would have any effect on low dielectric films.
Appellants do not dispute that Abeles discloses that the stress in PECVD
films may be controlled through inert gas dilution. Grill, Li, and Abeles are

2 Only those arguments actually made by Appellants have been considered in
this decision. Arguments which Appellants could have made but chose not
to make have not been considered and are deemed to be waived. See 37
C.F.R. § 41.37(c)(1)(vii) (2007).
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all directed to films that are deposited by a PECVD process. (FF 5, 8, and
9). Therefore, one of ordinary skill in the art would have reasonably
expected the methods disclosed by Abeles would have applied to Grill,
because each employs the same deposition technique. Further, although Li
is primarily directed to inorganic dielectric layers, Li recognizes that tensile
stress is an important problem in low dielectric layers. (See FF 7). Thus,
one of ordinary skill in the art would have applied Abeles’s method to
Grill’s dielectric layers to control the stress in the layer.
Additionally, Appellants’ argument that Grill does not enable a low
dielectric film is without merit. Grill is specifically directed to low dielectric
constant materials (FF 4), and Appellants have produced no evidence that
one of ordinary skill in the art would have been unable to produce low
dielectric constant films as disclosed in Grill by selecting appropriate
amounts of cyclic organosiloxane.
Appellants contend that none of the prior art references disclose
controlling the ratio of flow rates to from about 0.10 to about 0.20 as recited
in the claims. However, in view of Abeles, Appellants have not provided
any evidence that the particular range of ratios of organosiloxane to inert gas
recited in the claims is anything other than optimization of art-recognized
result effective variables to provide a desired stress to the low dielectric
films. Although Abeles does not specifically disclose in what way the ratio
of organosiloxane to inert gas and pressure must be varied in order to
achieve a particular level of tensile or compressive stress, Appellants have
not sufficiently demonstrated that one of ordinary skill in the art would have
been unable to determine the ratio and pressure required to obtain a desired
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stress or that the stress in the films obtained with the ratios recited in the
claims would have been unexpected.
Appellants further argue that the ratio of inert gas alone does not
permit predictable control over the stress for a low dielectric constant film.
Appellants contend that a number of other variables such as oxygen flow
rate and/or power levels influence the stress of the low dielectric constant
film citing to the difference in stress obtained at identical ratios in the
comparative examples disclosed in the Specification. (Reply Brief filed
January 22, 2008, hereinafter “Rep. Br.,” 4). That other variables besides
the ratio of organosiloxane to inert gas may affect the tensile stress of the
resulting dielectric film, does not mean that adjusting the ratio of
organosiloxane to inert gas alone would fail to provide a predictable result in
the stress of the film. Indeed, Appellants’ Specification attributes the control
of the stress of the film to the ratio of organosiloxane to inert gas and
pressure. (FF 2 and 3). These are the same two variables disclosed by
Abeles as providing control over the stress of the film. (FF 9). Thus,
Appellants’ arguments are not persuasive of reversible error.
For claim 8, Appellants have not presented any separate arguments.
Therefore, we affirm the rejection of claim 8 for the same reasons.

CONCLUSION
Appellants have failed to demonstrate that the Examiner reversibly
erred in determining that it would have been obvious to one of ordinary skill
in the art to adjust the ratio of a total flow rate of one or more cyclic
organosiloxanes to a total flow rate of one or more inert gases in the gas
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mixture disclosed in Grill, to from about 0.10 to about 0.20 as recited in the
appealed claims, in view of Li and Abeles.

ORDER
We affirm the Examiner’s decision rejecting claims 1-7 and 9-20
under 35 U.S.C. § 103(a) as being unpatentable over Grill in view of Li and
Abeles.
We affirm the Examiner’s decision rejecting claim 8 under 35 U.S.C.
§ 103(a) as being unpatentable over Grill in view of Li and Abeles, and
further in view of Lukas.
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)(v).
AFFIRMED

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