Ex Parte Coon et al

Patent Trial and Appeal Board

Dec 20, 2012

11878540 (P.T.A.B. Dec. 20, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte DEREK COON and ANDREW J. HAZELTON
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Appeal 2010-010394
Application 11/878,5401
Technology Center 2800
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Before MARC S. HOFF, GREGORY J. GONSALVES,
and ANDREW J. DILLON, Administrative Patent Judges.

HOFF, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from a final rejection of
claims 1-8 and 27-34.2 We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

STATEMENT OF THE CASE
Appellants’ invention is an immersion lithography system having a
fluid material in the space between a workpiece such as a wafer and the last-

1 The real party in interest is Nikon Corporation.
2 Claims 9-26 have been cancelled.
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Application 11/878,540

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stage optical member such as the lens of the optical system for projecting the
image of a reticle onto the workpiece (Spec. 1). Appellants disclose a fluid
control system to retain the fluid within and in the vicinity of the exposure
area (Spec. 1-2). Pressurized gas is supplied from outlets 25 (Fig. 5) at
sufficient velocity to confine the liquid (Spec. ¶¶ [0031], [0032]).
Independent claim 1, reproduced below, is representative of the
subject matter on appeal.
1. An immersion lithography apparatus comprising:
an optical member, a gap defined between the optical member and a
surface disposed opposite the optical member being filled with an immersion
liquid; and
a fluid control device including a gas outlet through which a gas is
supplied to prevent the immersion liquid from entering a surrounding area
external to an exposure area, wherein a flow velocity of the gas supplied
from the gas outlet is determined based on a contact angle between the
immersion liquid and the surface.

REFERENCE
Lof US 7,081,943 B2 July 25, 2006

REJECTIONS
Claims 1-6, 8, 27-32, and 34 stand rejected under 35 U.S.C. § 102(e)
as being anticipated by Lof.
Claims 7 and 33 stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Lof.

ISSUE
Appellants contend that Lof does not teach, expressly or inherently,
determining a flow velocity of the gas supplied from the gas outlet based on
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a contact angle between the immersion liquid and the surface, as the
independent claims recite (App. Br. 17). The Examiner finds that Lof’s
teachings show that it would be necessary for Lof to consider the contact
angle of the liquid and the surface (Ans. 4).
Appellants’ arguments present us with the following issue:
Does Lof teach, either expressly or inherently, determining a flow
velocity of the gas supplied from the gas outlet based on a contact angle
between the immersion liquid and the surface?

PRINCIPLES OF LAW
Under the doctrine of inherency, if a claimed element is not expressly
disclosed in a prior art reference, the reference nevertheless anticipates the
claim if the missing element is necessarily present in the reference, and it
would be so recognized by skilled artisans. Rosco, Inc. v. Mirror Lite Co.,
304 F.3d 1373, 1380 (Fed. Cir. 2002) (citations omitted). To anticipate the
claim, the missing element must be necessarily present in the prior art—not
merely probably or possibly present. Id.
“Inherency, however, may not be established by probabilities or
possibilities. The mere fact that a certain thing may result from a given set of
circumstances is not sufficient.” In re Robertson, 169 F.3d 743, 745 (Fed.
Cir. 1999) (citations omitted) (internal quotation marks omitted).

ANALYSIS
CLAIMS 1-6, 8, 27-32, AND 34
The independent claims recite a fluid control device including a gas
outlet through which a gas is supplied to prevent immersion liquid from
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entering a surrounding area external to an exposure area (claim 1), wherein a
flow velocity of the gas supplied from the gas outlet is determined based on
a contact angle between the immersion liquid and the surface (claims 1
and 27).
The Examiner finds that Lof inherently teaches that flow velocity is
determined based on the contact angle between the immersion liquid and the
surface. Lof teaches that “[t]he overpressure on the gas inlet 15, vacuum
level on the outlet 14 and geometry of the gap are arranged so that there is a
high-velocity gas flow inwards that confines the liquid” (col. 7, ll. 3-6).
From that teaching, the Examiner finds that
it would be necessary to take into consideration the contact
angle of the liquid and the surface, since the contact angle is a
measure of the degree of attraction, or confinement, of the
liquid on the surface. This arrangement would require a high
enough velocity gas flow in order to sufficiently confine the
liquid within the exposure area.
(Ans. 4).
A finding of inherency requires that the missing element is necessarily
present in the reference. See Rosco, 304 F.3d at 1380. The Examiner has
provided argumentation, but not evidence, regarding the proposition that the
contact angle between immersion liquid and the surface was necessarily
considered in Lof. The Examiner provides no factual support for the
assertion that it would be necessary to consider the contact angle of the
liquid and the surface (see Reply Br. 4). We agree with Appellants that the
Lof reference does not even discuss the contact angle (Reply Br. 2).
In response to Appellants’ argument that Lof did not consider the
contact angle, but merely chose a very high gas velocity (i.e., the speed of
sound) (App. Br. 21; Lof col. 7, ll. 35-37), the Examiner argues that Lof’s
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choice of the speed of sound is only pertinent for its particular arrangement
and is not applicable for other liquids or surfaces (Ans. 8). We are
unpersuaded by the Examiner that this inapplicability supports an argument
that the contact angle between immersion liquid and surface was necessarily
considered in Lof.
We find that the Examiner erred in rejecting claims 1-6, 8, 27-32, and
34 as being anticipated by Lof. We will not sustain the Examiner’s § 102
rejection.
CLAIMS 7 AND 33
Claims 7 and 33 depend from claims 1 and 27 respectively.
Accordingly, we will not sustain the § 103 rejection of claims 7 and 33, for
the same reasons expressed supra with respect to parent claims 1 and 27.

CONCLUSION
Lof does not teach, either expressly or inherently, determining a flow
velocity of the gas supplied from the gas outlet based on a contact angle
between the immersion liquid and the surface.

DECISION
The Examiner’s decision rejecting claims 1-8 and 27-34 is reversed.

REVERSED

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