Ex Parte Yueh et al

Board of Patent Appeals and Interferences

Mar 12, 2010

10687288 (B.P.A.I. Mar. 12, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte WANG YUEH, HUEY-CHIANG LIOU, HAI DENG, and
HOK-KIN CHOI
____________

Appeal 2009-006467
Application 10/687,288
Technology Center 1700
____________

Decided: March 12, 2010
____________

Before LINDA M. GAUDETTE, KAREN M. HASTINGS, and
JEFFREY B. ROBERTSON, Administrative Patent Judges.

ROBERTSON, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s final
rejection of pending claims 21-35. (Appeal Brief filed March 21, 2008,
hereinafter “App. Br.,” 3; Final Rejection mailed June 28, 2007, hereinafter
“Final”). We have jurisdiction pursuant to 35 U.S.C. § 6(b).
We REVERSE and ENTER A NEW GROUND OF REJECTION
under 37 C.F.R. § 41.50(b).
STATEMENT OF THE CASE
Appeal 2009-006467
Application 10/687,288

2
Appellants describe a method of accomplishing photolithography that
is said to result in substantially reduced line wide roughness (LWR). (Spec.
[0024].) Claims 21 and 27, reproduced below, are representative of the
subject matter on appeal.
21. A method comprising:
depositing a layer on a substrate;
depositing a non-chemically amplified photoresist layer upon
the layer, the non-chemically amplified photoresist layer having
a developer-soluble resin and a photoactive compound, the
photoactive compound inhibiting solubility of the developer-
soluble resin;
exposing selected portions of the non-chemically amplified
photoresist layer to an extreme ultra-violet light source such
that solubility of the selected portions of the non-chemically
amplified photoresist layer is promoted; and
developing the exposed portions of the non-chemically
amplified photoresist layer.

27. The method of claim 21, wherein the non-chemically
amplified photoresist layer does not include a photo-acid
generator (PAG).

(Claims App, pp. 15-16.)
THE REJECTIONS
The Examiner rejected claim 27 under 35 U.S.C. § 112, first
paragraph, as failing to comply with the written description requirement.
The Examiner rejected claims 21-25 and 30-34 under 35 U.S.C. §
103(a) as being unpatentable over Takemura (U.S. 5,759,739 (issued June 2,
1998)) in view of Sun (US 2005/0074699 A1, (published Apr. 7, 2005)).
The Examiner rejected claims 21, 26, 30, and 35 under 35 U.S.C. §
103(a) as being unpatentable over Cathey (U.S. 5,358,599 issued Oct. 25,
1994) in view of Sun.
Appeal 2009-006467
Application 10/687,288

3
The Examiner rejected claims 27-29 under 35 U.S.C. § 103(a) as
being unpatentable over Cathey in view of Sun, and further in view of Zhang
(US 2004/0204328 A1, (published Oct. 14, 2004)) and Asakura (U.S.
6,261,738 B1, (issued Jul. 17, 2001)).

ISSUES
In rejecting claim 27, the Examiner found that the photoactive
compound (PAC) is a photoacid generator (PAG), and therefore there is no
disclosure in the Specification that the non-chemically amplified generator
does not include a photoacid generator. (Examiner’s Answer entered June
11, 2008, hereinafter “Ans.,” 3.)
In rejecting the claims over the cited prior art, the Examiner found
that both Takemura and Cathey fail to disclose that the photoresist layer is
non-chemically amplified. (Ans. 4-6.) The Examiner found that Sun
discloses that a chemically amplified photoresist layer can be replaced with a
non-chemically amplified photoresist layer, which can then be used to
perform photolithographic processes at wavelengths less than 365 nm
including the extreme ultraviolet light recited in the claims. (Ans. 5 and 6.)
The Examiner determined that it would have been obvious to replace the
photoresist layers of Takemura or Cathey with the non-chemically amplified
photoresist layers of Sun to perform photolithographic processes in a shorter
wavelength range. (Id.)
Appellants contend that the Specification discloses that photoactive
compounds are different than photoacid generators and the Specification
discloses embodiments that exclude a photoacid generator. (App. Br. 8;
Reply Brief filed August 6, 2009, (hereinafter “Rep. Br.”) 2-3.)
Appeal 2009-006467
Application 10/687,288

4
Appellants argue that Sun does not disclose non-chemically amplified
photoresists useful for extreme UV (EUV) lithography. (App. Br. 10.) In
particular, Appellants argue that Sun’s disclosure:
should not be construed to encompass the next-generation EUV
lithography which uses a much smaller wavelength of about
13nm. Furthermore, materials suitable for DUV lithography
commonly are not suitable for EUV lithography. Accordingly,
the statement in Sun should not be construed to mean that non-
chemically amplified photoresists in general are suitable for
EUV.

(App. Br. 10.)
Appellants also argue that Takamura and Cathey cannot be combined
with Sun because Sun is directed to non-chemically amplified photoresists
and Takamura and Cathey are directed to chemically amplified photoresists.
(App. Br. 11 and 12.)
The following dispositive issues arise from Appellants’ contentions:
Have Appellants identified error in the Examiner’s finding that the
Specification does not adequately describe a “non-chemically amplified
photoresist layer [that] does not include a photo-acid generator (PAG)” as
recited in claim 27?
Have Appellants identified error in the Examiner’s determination that
Sun discloses non-chemically amplified photoresists for extreme UV
lithography?

FINDINGS OF FACT
The record supports the following findings of fact (FF) by a
preponderance of the evidence.
Appeal 2009-006467
Application 10/687,288

5
1. Appellants’ Specification discloses that typical prior art non-
chemically-amplified photoresists were found to be inadequate as
photoresist technology moved toward smaller wavelengths, e.g.
deep ultra-violet (DUV) with wavelengths of 248 nm or 193 nm,
due to the inability of the photoresists to become more transparent
in the DUV region. (Spec. [0003].)
2. Appellants’ Specification states that chemically-amplified
photoresists were developed to address the limitation of chemically
amplified photoresists. (Spec. [0003].)
3. Appellants’ Specification states “[f]or chemically amplified
photoresists, the mechanism is different [than for non-chemically-
amplified photoresists]. Instead of PAC, Photoacid generator
(PAG) is used.” (Spec. [0005].)
4. Appellants’ Specification states “[e]mbodiments of the invention
provide a non-chemically amplified photoresist (i.e., does not
include PAG), which results in reduced LWR.” (Spec. [0029].)
5. Appellants’ Specification states “[f]or one embodiment the
photoresist is applied in the EUV technology (e.g., wavelength is
13.4 nm).” (Spec. [0030].)
6. Takemura discloses a chemically amplified photoresist
composition including three components; an alkali-soluble resin, a
dissolution inhibitor, and a photoacid generator. (Col. 1, ll. 10-12;
col. 2, ll. 29-32.)
7. Takemura discloses “[t]he resulting positive resist composition is
highly sensitive to high energy radiation such as deep ultraviolet
rays, electron rays, and X rays. . . .” (Col. 2, ll. 37-39.)
Appeal 2009-006467
Application 10/687,288

6
8. Cathey discloses a photoresist including a photosensitive resin and
a photoacid generator, i.e., a chemically amplified photoresist.
(Col. 4, ll. 30-44.)
9. Sun discloses: “due to the extraordinarily thin photoresist, this
invention opens an opportunity to replace the ever troubling
chemically amplified photoresist with non-chemically amplified
photoresists for the photolithography process of KrF or shorter
wavelengths.” (Para. [0039].)
10. Sun discloses a protective layer that possesses light absorbing
properties at wavelengths of “less than about 500 nm (e.g. 436 nm,
365 nm, 248 nm, 193 nm, 157 nm, 13 nm, 11 nm, 4, nm, and X-
ray).” (Para. [0016].)
11. Sun discloses an example with a commercially available non-
chemically amplified photoresist that is exposed at a wavelength of
365 nm. (Para. [0050].)
12. Asakura discloses:
it becomes clear that chemical and thermal stability of a latent
catalyst is vital for a chemically amplified resist and that latent
acids which can work in a non-chemically amplified resist are
not necessarily applicable to chemically amplified resists
because of the different acid diffusion requirements, acid
strength requirements and thermal and chemical stability
requirements.

(Col. 19, ll. 37-43.)

PRINCIPLES OF LAW
To satisfy the written description requirement, a patent applicant must
“convey with reasonable clarity to those skilled in the art that, as of the filing
Appeal 2009-006467
Application 10/687,288

7
date sought, he or she was in possession of the invention.” Vas-Cath Inc. v.
Mahurkar, 935 F.2d 1555, 1563-64 (Fed. Cir. 1991) (emphasis omitted).
The Examiner bears the initial burden, on review of prior art or on any
other ground, of presenting a prima facie case of unpatentability. In re
Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992). “‘[R]ejections on
obviousness grounds cannot be sustained by mere conclusory statements;
instead, there must be some articulated reasoning with some rational
underpinning to support the legal conclusion of obviousness.’” KSR Int’l.
Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007), quoting In re Kahn, 441 F.3d
977, 988 (Fed. Cir. 2006).

ANALYSIS
Written Description-Claim 27
We agree with Appellants that the Specification provides sufficient
written descriptive support for the limitation “non-chemically amplified
photoresist layer does not include a photo-acid generator (PAG).”
Appellants’ Specification provides literal support for the recited limitation.
(FF 4.) Moreover, Appellants’ Specification clearly distinguishes between
chemically amplified photoresists employing a PAG and non-chemically
amplified photoresists employing a PAC. (FF 1-3.) Therefore, the
Examiner’s finding that PAG’s are a subset of PAC’s and thus may not be
properly excluded from claim 27 is not adequately supported by the record.
The Examiner has not provided sufficient basis that Appellants have failed
to convey with reasonable clarity to one of skilled in the art that they were in
possession of the subject matter of claim 27.

Appeal 2009-006467
Application 10/687,288

8
Prior Art Rejections
We are persuaded by Appellants’ arguments that the combination of
Takemura or Cathey with Sun fails to fairly suggest the recited method.
Specifically, while Sun suggests that chemically amplified photoresists may
be replaced with non-chemically amplified photoresists at KrF or shorter
wavelengths, Sun only discloses commercial non-chemically amplified
photoresists that are exposed at 365 nm, not in the EUV region. (FF 11.)
Although Sun discloses protective layers with light absorbing properties in
the EUV region (13nm), Sun does not specifically disclose non-chemically
amplified photoresists exposed to such shorter wavelengths. (See FF 8-11.)
Appellants’ arguments that materials for lithography performed at
different UV wavelength ranges, such as DUV, are not necessarily suitable
for EUV lithography are supported by Appellants’ Specification as well as
Asakura. Appellants’ Specification discloses that conventional non-
chemically amplified photoresists are not suitable for DUV lithography. (FF
1.) Moreover, Asakura discloses that latent acids generated from the PAG in
chemically amplified resists are not necessarily applicable to non-chemically
amplified photoresists. (FF 12.) Accordingly, the Examiner has not
provided a sufficient basis that the materials for the chemically amplified
photoresists disclosed in Takemura and Cathey would be suitable to function
as non-chemically amplified photoresists in the EUV region. Therefore we
cannot sustain the Examiner’s rejections.

NEW GROUND OF REJECTION
The following new ground of rejection is entered pursuant to 37
C.F.R. § 41.50(b).
Appeal 2009-006467
Application 10/687,288

9
Claims 21-35 are rejected under 35 U.S.C. § 112, first paragraph,
because the Specification, while being enabling for PAC’s of the formula
disclosed in Figure 4, does not reasonably provide enablement for the
general recitation of “photoactive compound” recited in the claims. The
Specification does not enable any person skilled in the art to which it
pertains, or with which it is most nearly connected, to make and use the
invention commensurate in scope with these claims for the reasons
explained below.

ADDITIONAL FINDINGS OF FACT
The record supports the following findings of fact (FF) by a
preponderance of the evidence.
13. With respect to the photoactive compound, Appellants’
Specification states:
Figure 4 illustrates the synthesis of a PAC for use as a
component of a photoresist in accordance with one embodiment
of the invention. As shown in Figure 4, synthesis 400,
produces PAC 410 that includes a ballast group. The ballast
group, R, may be any cage phenyl, or phenyl-substituted group.
The photo-speed, and developer solubility, can be modified, by
varying the ballast group (e.g., between electron donating and
electron withdrawing).

(Spec. [0022].)
14. Appellants’ Figure 4 is reproduced below:
Appeal 2009-006467
Application 10/687,288

10

Figure 4 above depicts the synthesis 400 of a photoactive compound 410.
(See FF 13.)
15. Appellants’ Specification describes one example of the reaction of
a photoactive compound upon exposure to a light source. (Spec.
[023], Fig. 5.)
16. Appellants’ Specification describes a general process for
performing a method of depositing and developing a photoresist.
(Spec. [0024]-[0028]; Fig. 6.)

PRINCIPLES OF LAW

“To satisfy the enablement requirement of § 112, ¶ 1, a patent
application must adequately disclose the claimed invention so as to enable a
person skilled in the art to practice the invention at the time the application
was filed without undue experimentation.” In re Swartz, 232 F.3d 862, 863
(Fed. Cir. 2000) (citation omitted).
Appeal 2009-006467
Application 10/687,288

11
The scope of the claims must not be broader than the scope of the
enabling description in the specification. See Nat’l Recovery Tech., Inc. v.
Magnetic Separation Systems, Inc., 166 F.3d 1190, 1196 (Fed. Cir. 1999).
“The scope of enablement, in turn, is that which is disclosed in the
specification plus the scope of what would be known to one of ordinary skill
in the art without undue experimentation.” Id. (citation omitted).
To determine whether the necessary experimentation is undue, we
look at factors including “(1) the quantity of experimentation necessary, (2)
the amount of direction or guidance presented, (3) the presence or absence of
working examples, (4) the nature of the invention, (5) the state of the prior
art, (6) the relative skill of those in the art, (7) the predictability or
unpredictability of the art, and (8) the breadth of the claims.” In re Wands,
858 F.2d 731, 737 (Fed. Cir. 1988).
Arts based on chemical reactions may be unpredictable. In re Fisher,
427 F.2d 833, 839 (C.C.P.A. 1970). “In cases involving unpredictable
factors, such as most chemical reactions and physiological activity, the
scope of enablement obviously varies inversely with the degree of
unpredictability of the factors involved.” Id.

ANALYSIS
Independent claims 21 and 30 generally recite a “photoactive
compound” which promotes the solubility of a selected portion of a non-
chemically amplified photoresist exposed to an extreme ultra-violet light
source. Thus, the claims with respect to the photoactive compound are
broad. However, Appellants’ only description with respect to the
photoactive compound is in conjunction with the synthesis of the particular
Appeal 2009-006467
Application 10/687,288

12
limited genus of photoactive compounds depicted in Figure 4. (FF 13, 14.)
While the Specification describes varying the R group on the depicted
photoactive compound (FF 13), Appellants provide no other guidance as to
what compounds, other than those having the chemical structure depicted in
Figure 4, would be useful in the claimed invention.
In addition, the Specification only provides one example showing
exposure of the PAC compound to a light source. (FF 15.) As pointed out
by Appellants, the materials suitable or DUV lithography commonly are not
suited for EUV lithography. (App. Br. 10.) Moreover, Asakura discloses
that photoactive compounds, which can work in a non-chemically amplified
resist are not necessarily applicable to chemically amplified resists. (FF 12.)
Therefore, the level of predictability in the lithography art is low.
Accordingly, because of the breadth of the claims, lack of direction or
guidance and working examples provided by Appellants, and the
unpredictability of the art, and state of the prior art, Appellants’
Specification does not provide enablement for the full scope of photoactive
compounds recited in the claims.
Dependent claims 23 and 33, which recite that the photoactive
compound comprises a phenyl group, are also not sufficiently enabled
because the claims lack the base structure depicted in Figure 4.

CONCLUSION
Appellants have identified error in the Examiner’s finding that the
Specification does not adequately describe “non-chemically amplified
photoresist layer does not include a photo-acid generator (PAG)” as recited
in claim 27.
Appeal 2009-006467
Application 10/687,288

13
Appellants have identified error in the Examiner’s determination that
Sun discloses non-chemically amplified photoresists for extreme UV
lithography.
Claims 21-35 are subject to a new ground of rejection under 35 U.S.C.
§ 112, first paragraph.

ORDER
We reverse the Examiner’s rejections of claims 21-35 under 35 U.S.C.
§§ 112, first paragraph, and 103(a).
This decision contains a new ground of rejection pursuant to
37 C.F.R. § 41.50(b). 37 C.F.R. § 41.50(b) also provides that the
Appellants, WITHIN TWO MONTHS FROM THE DATE OF THE
DECISION, must exercise one of the following two options with respect to
the new ground of rejection to avoid termination of the appeal as to the
rejected claims:
(1) Reopen prosecution. Submit an appropriate
amendment of the claims so rejected or new evidence relating
to the claims so rejected, or both, and have the matter
reconsidered by the Examiner, in which event the proceeding
will be remanded to the Examiner . . .

(2) Request rehearing. Request that the proceeding be
reheard under § 41.52 by the Board upon the same record. . . .

No time period for taking any subsequent action in connection with
appeal may be extending under 37 C.F.R. § 1.136(a)(1)(v).

REVERSED
NEW GROUND OF REJECTION (37 C.F.R. §41.50(b))

Appeal 2009-006467
Application 10/687,288

14

rvb

INTEL/BSTZ
BLAKELY SOKOLOFF TAYLOR & ZAFMAN LLP
1279 OAKMEAD PARKWAY
SUNNYVALE, CA 94085-4040