Ex Parte Srivastava

Board of Patent Appeals and Interferences

Nov 22, 2010

10755617 (B.P.A.I. Nov. 22, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte ASEEM K. SRIVASTAVA
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Appeal 2009-013335
Application 10/755,617
Technology Center 1700
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Before PETER F. KRATZ, JEFFREY T. SMITH, and MARK NAGUMO,
Administrative Patent Judges.

NAGUMO, Administrative Patent Judge.

DECISION ON APPEAL1

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
(paper delivery mode) or the “NOTIFICATION DATE” (electronic delivery
mode) shown on the PTOL-90A cover letter attached to this decision.

Appeal 2009-013335
Application 10/755,617

A. Introduction2
Aseem K. Srivastava (“Srivastava”) timely appeals under
35 U.S.C. § 134(a) from the final rejection3 of claims 1-26. We have
jurisdiction under 35 U.S.C. § 6. We REVERSE.
The subject matter on appeal relates to a baffle plate assembly, also
known as a gas distribution plate assembly. Such plate assemblies are used,
for example, to distribute a reactive plasma gas over a substrate such as a
photoresist-covered wafer to “ash” the no-longer needed photoresist.
The 617 Specification teaches that prior art baffle plates are “of a single or
dual baffle plate construction” and may include an impingement plate.
(Spec. 2 [0005].) Prior art single baffle plates are said to be made of an
expensive ultra pure aluminum alloy, while the lower plate of a dual baffle
plate assembly is said to be aluminum and the upper plate quartz (or
sapphire-coated quartz to prevent etching by for fluorine plasmas). (Id.)
The temperature of the upper quartz baffle plates of the prior art, which are
heated by exposure to plasma entering the process chamber and by
associated ultraviolet radiation, is said to be difficult to control. (Id.
at 3 [0006].) Moreover, recombination of reactive plasma species in the
plasma itself and at surfaces, including the baffle plates, is said to decrease

2 Application 10/755,617, Gas Distribution Plate Assembly for Plasma
Reactors, filed 12 January 2004. The specification is referred to as the
“617 Specification,” and is cited as “Spec.” The real party in interest is
listed as Axcelis Technologies, Inc. (Appeal Brief, filed 18 December 2007
(“Br.”), 2.)
3 Office action mailed 12 July 2007 (a non-final office action; cited as
“OA”).
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Application 10/755,617

the efficiency of the plasma processing. (Id. at [0008].) The improved
baffle plate assembly comprises a single baffle plate with apertures and a
centrally located impingement device having a stem fixed to the baffle plate
and an apertureless cap at the other. (Id. at 8 [0029]-[0030].) The
impingement device radially deflects the plasma entering the process
chamber and thus protects the baffle plate assembly. In preferred
embodiments, the cap is about the same diameter, or slightly larger, than the
opening to the plasma chamber. (Id. at 9 [0030-[0031].) The impingement
device is cooled by thermal contact between the impingement device and the
baffle plate, which in turn may be cooled by liquids circulated to internal
cooling passages. (Id. at [0031.)
Representative Claim 1 reads:
1. A baffle plate assembly for distributing gas flows into an
adjacent process chamber containing a semiconductor wafer to
be processed, comprising:
a single generally circular planar gas distribution portion
having a plurality of apertures therein;
a flange surrounding the gas distribution portion; and
an apertureless impingement device centrally attached to
the gas distribution portion,
wherein the device includes
a generally circular cap and
a stem,
the stem being in thermal contact with the
gas distribution portion.
(Claims App., Br. 19; indentation, paragraphing, and emphasis added.)
Independent claim 13 is drawn to a plasma ashing device comprising
a baffle plate assembly similar to the one covered by claim 1, but with the
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Application 10/755,617

further limitation that the cap of the apertureless impingement device have a
diameter about equal to the diameter of the process chamber opening that
receives plasma from the plasma generator.
The Examiner has maintained the following grounds of rejection:4
A. Claims 1, 5, 11-15, 19, 25, and 26 stand rejected under
35 U.S.C. § 102(a) in view of Kinnard.5
B. Claims 2-4 and 16-18 stand rejected under 35 U.S.C. § 103(a)
in view of Kinnard.
C. Claims 6-9 and 20-23 stand rejected under 35 U.S.C. § 103(a)
in view of Kinnard and Hao.6
D. Claims 10 and 14 stand rejected under 35 U.S.C. § 103(a) in
view of Kinnard and Chen.7
B. Discussion
Findings of fact throughout this Opinion are supported by a
preponderance of the evidence of record.
Srivastava argues that the Examiner erred in finding that Kinnard
describes an anticipatory baffle plate, because Kinnard describes a dual
baffle plate assembly rather than a single gas distribution portion; because

4 Examiner’s Answer mailed 10 July 2008 (“Ans.”).
5 David B. Kinnard and Daniel B. Richardson, Actively-Cooled Distribution
Plate for Reducing Reactive Gas Temperature in a Plasma Processing
System, U.S. Patent 6,635,117 B1 (21 October 2003), based on an
application filed 26 April 2000.
6 Fangli Hao and Rajinder Dhindsa, Gas Distribution Apparatus for
Semiconductor Processing, U.S. Patent 6,415,736 B1 (2002).
7 Chen-An Chen and Karl Anthony Littau, Chemical Vapor Deposition
Manifold, U.S. Patent 6,024,799 (2000).
4
Appeal 2009-013335
Application 10/755,617

the sapphire impingement plate described by Kinnard does not include a
stem, but is attached to the upper baffle place by screws; and because the
impingement plate is “essentially floating from a thermal perspective.”
(Br. 12, last para.)
The Examiner maintains that Kinnard describes an anticipatory baffle
plate (and an asher comprising such a baffle plate, covered by independent
claim 13) in Figures 1, 3, and 4. Figures 3 and 4 are reproduced below. (In
the following text, labels are shown in bold font for clarity regardless of
their font in the original document.)
{Kinnard Figures 3 and 4}

{Figures 3 and 4 are top and side views of a dual baffle plate assembly}
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Application 10/755,617

The Examiner finds that the Figures show a baffle plate assembly
having a single generally circular planar gas distribution portion 60 [sic: 16]
with a plurality of apertures 30, a surrounding flange 48, an apertureless
impingement device 62 having a generally circular cap and a stem 54
(shown in Figure 4) that is in thermal contact with the gas distribution
portion 60 [16] (Ans. 4.)
The Examiner argues that Srivastava’s supporting 617 Specification,
in Figures 3 and 4, shows a “‘single’ gas distribution portion 54” that has
two surfaces that function as “baffles that divert flows in much the same way
as the Examiner’s citations to Kinnard.” (Ans. 12.)
{617 Specification Figure 3 is reproduced below:}

{Figure 3 shows a side view of a baffle plate and impingement device}
A reference is anticipatory under § 102 if it describes, explicitly or
inherently each and every element required by the claimed invention,
arranged or combined in the same way as recited in the claim. In re Gleave,
560 F.3d 1331, 1334 (Fed. Cir. 2009). Inherency, however, may not be
established by probabilities or possibilities. In re Oelrich, 666 F.2d 578, 581
(CCPA 1981). Moreover, although claim terms are to be read broadly, “the
person of ordinary skill in the art is deemed to read the claim term not only
in the context of the particular claim in which the disputed term appears, but
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Application 10/755,617

in the context of the entire patent, including the specification.” Phillips v.
AWH Corp., 415 F.3d 1303, 1313 (Fed. Cir. 2005) (en banc).
Here, the Examiner has equated what Kinnard names the “upper
baffle plate” with the “impingement device” recited in the claims. However,
as is apparent from Kinnard Figure 3 and the accompanying description,
upper baffle plate 14 has apertures 28 that are slightly larger than the
apertures 30 in the lower baffle plate 16. (Kinnard, col. 4, ll. 35-37; Kinnard
reverses the plate-labels in the text, relative to the figure.) Those apertures
negate anticipation if upper baffle plate 14 is regarded as part of the
impingement device, which the claims require to be apertureless. (Reply 7,
1st full para.) Moreover, Kinnard discloses distinct functions for the
impingement plate 62 (it distributes reactive plasma gases radially outwards
(Kinnard, col. 5, ll. 48-50) and the upper baffle plate 14 (it provides an
incremental pressure drop from the plasma tube exit to the processing
chamber that “imparts a laminar flow characteristic” to the downwardly
flowing gas (id. at ll. 56-65). (Reply, para. bridging 7-8.) Thus, the weight
of the evidence is that upper baffle plate 14 cannot be equated functionally
or structurally with the recited apertureless impingement plate.
Alternatively, it is possible the Examiner has misconstrued the
transitional term “comprising” in the present claims. Although
“comprising” opens the claimed subject matter to materials and structures
not recited in the claims, it cannot override exclusions within the body of the
claim. In particular, claims 1 and 13 recite that the apparatus comprises “a
single generally circular planar gas distribution portion having a plurality of
apertures” (emphasis added). Because interpreting “comprising” as opening
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Application 10/755,617

the claim to additional apertured plates would negate an express limitation of
the claim, that interpretation cannot be proper.
Finally, we note that the Examiner does not deny that the Kinnard
impingement plate 62 is attached to upper baffle plate 14 by screws 64. Not
having accepted the Examiner’s argument that the upper baffle plate is part
of an apertureless impingement device, we do not accept the Examiner’s
conclusion that standoffs 54 are part of an apertureless impingement device,
as that term is used in the claims. We also note that the Examiner has not
come forward with any evidence that Kinnard standoffs 54 are thermally
conductive. The Examiner’s argument, based on “rudimentary
thermodynamics,” that all tangible materials are in “thermal contact” via
some mode of heat transfer with everything else (Ans. 14, last para.) is not
well taken. The Examiner has failed to come forward with credible evidence
that persons having ordinary skill in the art would have understood the
“thermal contact” limitation in such an idealized fashion that it would have
no meaning in the plasma-processing laboratory or workplace. Glass or
ceramic rods, for example, when heated at one end, will eventually get hot,
but they are very poor heat conductors, and hence very poor “thermal
contacts” compared to metal rods. While it might be possible to show it that
a person having ordinary skill in the art would have recognized that Kinnard
used metal rods as standoffs (or, in an obviousness rejection, that it would
have been obvious to do so), the Examiner has failed to make such
arguments.
These differences between the claimed subject matter and the
embodiments disclosed by Kinnard negate anticipation. The Examiner has
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relied on the remaining references to establish the alleged obviousness of
further limitations in the remaining dependent claims. None of the
rejections of record remedy the deficiencies of Rejection A regarding the
independent claims. Accordingly, we REVERSE all the rejections of record.
C. Order
We REVERSE the rejection of claims 1, 5, 11-15, 19, 25, and 26
under 35 U.S.C. § 102(a) in view of Kinnard.
We REVERSE the rejection of claims 2-4 and 16-18 under
35 U.S.C. § 103(a) in view of Kinnard.
We REVERSE the rejection of claims 6-9 and 20-23 under
35 U.S.C. § 103(a) in view of Kinnard and Hao.
We REVERSE the rejection of claims 10 and 14 under
35 U.S.C. § 103(a) in view of Kinnard and Chen.
REVERSED
tc
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