Ex Parte Strang

Board of Patent Appeals and Interferences

Mar 29, 2011

10469592 (B.P.A.I. Mar. 29, 2011)

UNITED STATES PATENT AND TRADEMARK OFFICE
_________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte ERIC J. STRANG
__________

Appeal 2010-005966
Application 10/469,592
Technology Center 1700
___________

Before ADRIENE LEPIANE HANLON, CHUNG K. PAK, and
CATHERINE Q. TIMM, Administrative Patent Judges.

HANLON, Administrative Patent Judge.

DECISION ON APPEAL

A. STATEMENT OF THE CASE
This is an appeal under 35 U.S.C. § 134 from an Examiner’s decision
finally rejecting claims 1-5, 7-16, 20, 21, and 23-27. We have jurisdiction
under 35 U.S.C. § 6(b).
We AFFIRM.

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The subject matter on appeal is directed to a plasma processing
system and a method for supplying a gas to a plasma processing chamber.
The system combines a high-pressure pulsed gas flow with a continuous gas
flow. Spec. 3:14-18. According to the Appellant’s Specification:
During the short high pressure pulses, the gas flow is
temporarily directed normal to the wafer surface under high
pressure resulting in an increase in the pressure within a thin
layer adjacent to the wafer surface and a more narrow
distribution of the gas velocity directivity near the wafer
surface. This increases the number of adatoms [(i.e., the
chemical species to be deposited on the wafer surface)] at the
wafer surface and increases the probability of finding a specific
adatom moving in a direction normal to the surface.

Spec. 3:20-25.
The Appellant discloses that the combination of increasing the
number of adatoms at the wafer surface and/or increasing the probability of
finding a specific adatom moving in a direction normal to the wafer surface
can lead to “improved deposition within high aspect ratio features as well as
improved etch process performance.” Spec. 5:23-27.
Claim 1, reproduced below, is illustrative.
1. A plasma processing system comprising:

a plasma processing chamber including a plurality of
continuous flow shower-head orifices;

plural pulsed high-pressure injectors interspersed
between the plurality of continuous flow shower-head orifices;

said plural pulsed high-pressure injectors each being
separately connected to a gas feed line;

said plurality of continuous flow shower-head orifices
being connected to a common volume;
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at least one continuous flow gas valve configured to
provide a first gas to the chamber via the common volume and
the continuous flow shower head orifices;

at least one pulsed gas valve configured to provide a
second gas to the chamber via at least one of the gas feed lines
and its respective pressure injector; and

a controller coupled to each gas valve and programmed
to cause the continuous flow gas valve to provide the first gas
in a continuous flow having a flow rate of 100-500 sccm and to
cause the pulsed gas valve to provide the second gas in a pulsed
flow, each pulse having a flow rate of 1,000-10,000 sccm.

App. Br., Claims Appendix.1
Claim 12, the only other independent claim on appeal, recites a
method for supplying a gas to a plasma-processing chamber which
comprises, inter alia, the steps of:
injecting a first gas continuously from a continuous
shower-head orifice at a gas flow rate of between 100-500
sccm; [and]

pulsing a second gas cyclically from pulsed high-pressure
injectors at a cyclical flow rate of 1,000-10,000 sccm.

App. Br., Claims Appendix.
The following Examiner’s rejections are before us on appeal:
(1) Claims 1, 4, 5, 7, 8, 12-16, 20, 21, and 23-27 are rejected under
35 U.S.C. § 103(a) as unpatentable over the combination of Hanazaki2 and
Tomoyasu.3

1 Appeal Brief dated August 8, 2007.
2 US 6,287,980 B1 issued September 11, 2001.
3 US 5,888,907 issued March 30, 1999.
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(2) Claims 2 and 3 are rejected under 35 U.S.C. § 103(a) as
unpatentable over the combination of Hanazaki, Tomoyasu, and Chang.4
(3) Claims 9-11 are rejected under 35 U.S.C. § 103(a) as
unpatentable over the combination of Hanazaki, Tomoyasu, Koshiishi,5 and
Kai.6
B. ISSUE
Has the Appellant identified reversible error in the Examiner’s
conclusion that the combined teachings of Hanazaki and Tomoyasu render
obvious a controller programmed to cause the flow rates recited in claims 1
and 12 and the pulse duration and pulse rate recited in claims 26 and 27?
C. DISCUSSION
The Examiner finds that Hanazaki discloses a plasma processing
system comprising a plurality of continuous flow shower-head orifices and a
plurality of pulsed high-pressure injectors interspersed between the plurality
of continuous flow shower-head orifices. The Examiner finds that the
continuous flow shower-head orifices are connected to a common volume
and the plurality of pulsed high-pressure injectors are each separately
connected to a gas feed line. Ans. 4-5.7
The Examiner finds that Hanazaki does not expressly disclose:
at least one continuous flow gas valve configured to provide a
fist [sic, first] gas to the chamber via the common volume and
the continuous flow shower head orifices; at least one pulsed
gas valve configured to provide a second gas to the chamber via
at least one of the gas feed lines and its respective pressure
injector; and a controller coupled to each gas valve and

4 US 4,854,263 issued August 8, 1989.
5 US 5,928,963 issued July 27, 1999.
6 US 5,256,174 issued October 26, 1993.
7 Examiner’ Answer dated November 16, 2007.
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programmed to cause the continuous flow gas valve to provided
[sic, provide] the first gas in a continuous flow having a rage
[sic, range] of 100-500 sccm and to cause the pulsed gas valve
to provide the second gas in a pulsed flow, each pulse having a
flow rate of 100-1000 sccm [sic, 1,000-10,000 sccm].

Ans. 6.
The Examiner finds that Tomoyasu discloses a plasma processing
system for providing continuous and pulsed gas flows which includes
continuous and pulsed gas valves and a controller for controlling and
optimizing gas flow rates. The Examiner does not find that Tomoyasu
expressly discloses that the controller is programmed to cause the claimed
flow rates. However, the Examiner finds that Tomoyasu discloses that
“[i]ntervals and flow rates of the time-sharing open/close valves . . . are
optimized in consideration of parameters, such as etching rate, etching
selectivity, etched shaped, and process uniformity.” Ans. 6; Tomoyasu
8:61-64.
The Examiner concludes:
The prior art fairly and clearly teaches the use of a controller to
optimize flow rates and flow intervals in consideration of
known processing parameters (e.g. etching rate, etching
selectivity, etched shaped and process uniformity). This
positive suggestion of optimization would undoubtedly be more
than sufficient to lead one possessed with ordinary skill to vary
the flow rates and flow intervals based on desired processing
results.

Ans. 17.
The Appellant argues that the Examiner takes the position that “the
mere disclosure that flow rates can be ‘optimized’ is sufficient teaching for
one of ordinary skill in the art to select the specific high and low flow rates
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of Applicant’s claimed invention.” App. Br. 6. However, the Appellant
argues:
There is nothing in Tomoyasu et al. to suggest that optimizing
flow rates to achieve improved rate, selectivity, shape and
uniformity of an etch process will also result in improved
processing within high aspect ratio features as recognized by
the inventor. Thus, if one of ordinary skill in the art reading
Tomoyasu et al. were to optimize flow rates to achieve the
benefits disclosed in Tomoyasu et al., they would arrive at a
different range for this variable than is claimed by Applicant.

App. Br. 6.
The Appellant’s argument is not persuasive of reversible error. The
Appellant discloses that the pulsed flow not only improves deposition within
high aspect ratio features but also improves etch process performance.8
Spec. 5:23-27.
According to the Appellant:
[T]he prior art must disclose both the variable and some effect
that would cause one of skill in the art to optimize the variable
to be within the claimed range. This is commonly done by
identifying the same effect as disclosed in Appellants’
Specification. [Emphasis in original omitted.]

App. Br. 7.
In this case, Tomoyasu, like the Appellant, discloses that flow rates
affect etch process performance, i.e. etching rate, etching selectivity, etched
shape, and process uniformity. Tomoyasu 8:61-64. Thus, the
preponderance of the evidence of record establishes that a controller
programmed to cause the flow rates recited in claims 1 and 12 would have

8 The Appellant does not direct us to any disclosure in the Specification that
identifies the effects of the claimed continuous gas flow.
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been prima facie obvious in view of the teachings in Tomoyasu. See In re
Antonie, 559 F.2d 618, 620 (CCPA 1977) (the discovery of an optimum
value of a result effective variable in a known process is ordinarily within
the skill of the art).
As to claims 26 and 27, the Appellant argues that none of the cited
references disclose the recited pulse duration and pulse rate. App. Br. 8.
Pulse rate is merely the number of pulses per second and is a function
of the duration of the pulse and the duration between pulses (i.e., interval).
As discussed above, Tomoyasu discloses that the interval affects etch
process performance, i.e., etching rate, etching selectivity, etched shape, and
process uniformity. Tomoyasu 8:48-52, 61-64. As for the pulse duration,
one of ordinary skill in the art would have understood that an etching
reaction stops when the supply of reactive gas stops, as at the end of a pulse.
See Hanazaki 41:22-26. Thus, it would have been within the skill of the
ordinary artisan to adjust the pulse duration to achieve desired etch
characteristics, such as etching rate.
In sum, the preponderance of the evidence of record also establishes
that a controller, programmed to cause the pulse duration and pulse rate
recited in claims 26 and 27, would have been prima facie obvious in view of
the combined teachings of Hanazaki and Tomoyasu.
Finally, we note that the Appellant does not direct us to any evidence
of unexpected results. See Antonie, 559 F.2d at 620 (a prima facie case of
obviousness may be rebutted where the results of optimizing a variable are
unexpectedly good).
D. DECISION
The decision of the Examiner is affirmed.
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No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

sld

OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, L.L.P.
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ALEXANDRIA VA 22314