Ex Parte Strang

Patent Trial and Appeal Board

Aug 29, 2014

10469592 (P.T.A.B. Aug. 29, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
_________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte ERIC J. STRANG
__________

Appeal 2013-002323
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 a final rejection of
claims 1-5, 7-16, 20, 21, and 23-27. We have jurisdiction under 35 U.S.C.
§ 6(b).
We REVERSE.
The Appellant discloses a plasma processing system and a method of
supplying a gas to a plasma processing chamber using a high-pressure
pulsed gas flow. Spec. 3, ll. 14-18. The disclosed invention is said to solve
Appeal 2013-002323
Application 10/469,592

2
the problem of a lack of gas directivity in known plasma processors.1 See
Spec. 2, ll. 23-24.
According to the Appellant:
[An] object of the present invention [is] to provide a pressure
gradient local to a substrate surface. 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, ll. 19-25; see also Spec. 5, ll. 24-25.
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, ll. 23-27.
Claim 1 is representative of the subject matter on appeal and is
reproduced below from the Claims Appendix of the Appeal Brief dated May
17, 2012 (“Br.”). The limitation at issue is italicized.
1. A plasma processing system comprising:

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

1 The Appellant describes known systems as having “a low mass flow rate
(i.e. approximately 500 sccm argon equivalent) suitable for a low-pressure
process (i.e. 1 to 50 mTorr)).” Spec. 2, ll. 25-27.

Appeal 2013-002323
Application 10/469,592

3
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;

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 such
that, during each pulse, gas transport adjacent to a surface of a
substrate being processed affects at least one of an increase in
local number density of adatoms, or an increase in probability
of adatoms moving in a direction normal to the surface, to
improve processing within high aspect ratio features in the
substrate.

Claim 12, the other independent claim on appeal, recites a method for
supplying a gas to a plasma processing chamber comprising, inter alia, the
step of:
pulsing a second gas cyclically from pulsed high-pressure
injectors at a cyclical flow rate of 1,000-10,000 sccm such that,
during each pulse, gas transport adjacent to a surface of a
substrate being processed affects at least one of an increase in
local number density of adatoms, or an increase in probability
of adatoms moving in a direction normal to the surface, to
Appeal 2013-002323
Application 10/469,592

4
improve processing within high aspect ratio features in the
substrate.

Br. 18 (emphasis added).
The claims on appeal stand rejected as follows:
(1) claims 1, 4, 5, 7, 8, 12-16, 20, 21, and 23-27 under 35 U.S.C.
§ 103(a) as unpatentable over the combination of Hanazaki2 and Tomoyasu3;
(2) claims 2 and 3 under 35 U.S.C. § 103(a) as unpatentable over
the combination of Hanazaki, Tomoyasu, and Chang4; and
(3) claims 9-11 under 35 U.S.C. § 103(a) as unpatentable over the
combination of Hanazaki, Tomoyasu, Koshiishi,5 and Kai.6
B. DISCUSSION
A Decision on Appeal was previously entered in the instant
Application affirming the decision of the Examiner. See Decision on Appeal
dated March 31, 2011 (Appeal 2010-005966); Decision on Rehearing dated
August 1, 2011. The Appellant subsequently amended independent claims 1
and 12 to recite that the pulsed flow produces the following result:
[D]uring each pulse, gas transport adjacent to a surface of a
substrate being processed affects at least one of an increase in
local number density of adatoms, or an increase in probability
of adatoms moving in a direction normal to the surface, to
improve processing within high aspect ratio features in the
substrate.
Br. 16, 18 (emphasis added).

2 US 6,287,980 B1 issued September 11, 2001.
3 US 5,888,907 issued March 30, 1999.
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.
Appeal 2013-002323
Application 10/469,592

5
There is no dispute on this record that neither Hanazaki nor Tomoyasu
discloses a flow rate within the claimed range. Nonetheless, the Examiner
finds that Hanazaki teaches:
improv[ing] processing of high aspect ratio features, such that
during each pulse, gas transport adjacent to a surface of the
substrate is being processed affects at least one of an increase in
local number density of adatoms, or an increase in probability
of adatoms moving in a direction normal to the surface, to
improve processing within high aspect ratio features in the
substrate.
Ans. 5, 13.7
The Appellant argues:
[T]here is no evidence or technical reasoning on record to link
the flow rate variable with the claimed result asserted to be
taught by Hanazaki et al. [i.e., improving processing within
high aspect ratio features in a substrate]. That is, the Final
Action does not provide any analysis for why one skilled in the
art would use the flow rate variable to achieve the claimed
result.
Br. 10-11.
The Appellant’s argument is supported by the record. Hanazaki
discloses problems associated with wafers having a large diameter. A first
problem is that the absolute amount of ions, radicals, or the like reaching the
wafer surface varies between the central portion and the peripheral portion
of the wafer such that the etching rate, the etching shape, and the like are not
uniform across the wafer surface. Hanazaki, col. 3, ll. 33-41. A second
problem is RIE lag. Hanazaki, col. 3, ll. 42-51. Hanazaki describes RIE lag
as “a phenomenon that the etching rate depends on the pattern size (aspect
ratio) and varies with the pattern.” Hanazaki, col. 19, ll. 60-62.

7 Examiner’s Answer dated September 10, 2012.
Appeal 2013-002323
Application 10/469,592

6
The Examiner finds that RIE lag is a problem in high aspect ratio
processing. Ans. 23. However, the Examiner has not directed us to any
portion of Hanazaki disclosing that RIE lag is solved by varying the pulsed
flow rate. In the embodiment relied on by the Examiner, Hanazaki discloses
that the problems identified above are solved “by pulsatively introducing an
etching gas . . . into the buffer chamber and fluctuating the gas pressure in
the reaction chamber in the range of about 0.1 mTorr to about 200 mTorr.”8
Hanazaki, col. 4, ll. 14-23 (emphasis added); see also Hanazaki, col. 20, l.
64-col. 21, l. 9.
The Examiner also finds that Tomoyasu teaches “optimizing the flow
rate in consideration of etching rate, etching selectivity, etched shape and
process uniformity.” Ans. 7, 14. However, the Appellant argues that “there
is nothing in Tomoyasu et al. to suggest that optimizing or varying flow
rates to achieve improved rate, selectivity, shape and uniformity of an etch
process will also result in improved directivity and improved processing
within high aspect ratio features as recognized by the inventor.” Br. 11.
This argument is also supported by the record. Tomoyasu generally
discloses that flow rates “are optimized in consideration of parameters, such
as etching rate, etching selectivity, etched shaped, and process uniformity.”
Tomoyasu, col. 8, ll. 61-64. However, Tomoyasu does not disclose that
flow rate, especially a flow rate as high as 1,000-10,000 sccm, improves
directivity, and thus, improves processing within high aspect ratio features
in a substrate as recited in claims 1 and 12.

8 In this embodiment, Hanazaki discloses that etching gases were introduced
into the buffer chamber at mean gas flow rates of 50 sccm, a flow rate
significantly lower that the claimed flow rate of 1,000-10,000 sccm.
Hanazaki, col. 18, ll. 8-11.
Appeal 2013-002323
Application 10/469,592

7
The Examiner does not rely on the remaining prior art of record to
cure this deficiency in Tomoyasu. Therefore, the § 103(a) rejections are not
sustained.
C. DECISION
The decision of the Examiner is reversed.
REVERSED

cdc