Ex parte DAS et al.

Board of Patent Appeals and Interferences

Sep 3, 1998

08135324 (B.P.A.I. Sep. 3, 1998)

Application for patent filed October 13, 1993. The 1
instant application is a continuation of Serial Number
07/887,408, filed on May 19, 1992, and now abandoned; said
abandoned application is a continuation of Serial Number
07/682,574, filed on April 8, 1991, and now abandoned.
1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today
(1) was not written for publication in a law journal and
(2) is not binding precedent of the Board.
Paper No. 32
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________
Ex parte SIDDHARTHA DAS, HARRY H. FUJIMOTO
and HENRY GAW
________________
Appeal No. 95-3936
Application 08/135,3241
________________
ON BRIEF
________________
Before CAROFF, METZ and HANLON, Administrative Patent Judges.
METZ, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 from the
examiner's refusal to allow claims 10 and 12 through 14. The
Appeal No. 95-3936
Application 08/135,324
2
examiner has indicated in his advisory action (Paper Number 24
- mailed on June 9, 1994) that claims 15 through 17 and 23
through 25 are allowed. Claim 11 has been objected to in the
advisory action without explanation of the basis for the
objection. Accordingly, only claims 10 and 12 through 14 are
before us for consideration and claims 11, 15 through 17 and
23 through 25 form no issue in this appeal.
THE INVENTION
The claimed invention is directed to a process for
forming a photoresist pattern. The process comprises the
conventional steps of coating a wafer with a photoresist,
irradiating the photoresist with radiation of a predetermined
wavelength to generate photoacid defining a latent image in
said photoresist and baking the latent image formed by the
photoacid. Appellants discovered that by protecting the latent
image formed on the photoresist on the wafer after generation
of photoacid but before baking the latent image a sharper,
better defined image is obtained.
Claim 10, the sole independent claim before us, is
reproduced below for a more facile understanding of
appellants' claimed invention.
10. A process for forming a photoresist pattern
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Application 08/135,324
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comprising the steps of:

coating a wafer with a photoresist, said
photoresist producing a photoacid when irradiated
with radiation of a predetermined range of
wavelengths, said photoacid catalyzing a chemical
reaction when said photoresist is baked to increase
the solubility of said photoresist in the irradiated
areas with respect to the solubility of said
photoresist in the non irradiated areas;

irradiating said photoresist on said wafer with
said radiation of a predetermined wavelength to
generate said photoacid defining a latent image in
said photoresist on said wafer, said irradiating
step following said coating step;

preventing said photoacid from being
neutralized; and
baking said latent image in
photoresist on said wafer, said baking step
following said preventing step.
The examiner has not relied on any prior art to
reject the appealed claims.
Claims 10 and 12 through 14 stand rejected under 35
U.S.C. § 112, first paragraph, on the grounds that the
appealed claims are based on a disclosure which is only
"enabling" for nitrogen or water as the agent which prevents
the photoacid from being neutralized. We affirm.
OPINION
The question before us is whether appellants'
disclosure would have enabled the hypothetical person of
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ordinary skill in the art at the time appellants' invention
was made to make the claimed invention. In re Glass, 492 F.2d
1228, 1232, 181 USPQ 31, 34 (CCPA 1974). 35 U.S.C. § 112,
first paragraph, requires a reasonable correlation between the
scope of what is claimed and the scope of enablement provided
by appellants' specification to the person of ordinary skill
in the art. In re Vaeck, 947 F.2d 488, 495, 20 USPQ2d 1438,
1444 (Fed. Cir. 1991); In re Fisher 427 F.2d 833, 839, 166
USPQ 18, 24 (CCPA 1970).
Although the examiner's statement of the rejection
and underlying rationale in support of the rejection are not
models of clarity, we understand the rejection to be founded
on the examiner's determination that although claim 10
utilizes the language "preventing said photoacid from being
neutralized", appellants' disclosure only describes the use of
nitrogen and water as being useful for that purpose. The
examiner reasons that the two disclosed "species" do not
provide an adequate basis for the scope of the claim language
of "preventing said photoacid from being neutralized." The
examiner opines that in light of the unpredictability in the
art, except for the disclosure of nitrogen and water as being
useful, it would have required undue experimentation for the
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Application 08/135,324
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ordinarily skilled person in the art to determine other useful
agents for preventing neutralization.
Appellants argue that because the use of "chemical
ambients does not involve complex chemical reactions" (page 5
of the main brief), selection of "ambients" or suitable media
would have been readily ascertainable to one skilled in the
art by actually selecting an "ambient" or medium and
determining whether the photoacid becomes neutralized.
Appellants suggest by this argument that if the routineer
tests a candidate for the "ambient" or medium and it prevents
neutralization of photoacids then it is appellants' invention
and the disclosure is enabling. We disagree.
We consider appellants' position to be tantamount to
an invitation to the routineer to experiment. An invitation
to experiment does not constitute enablement, especially
where, as here, there is little or no guidance in the
specification which would direct the routineer in his or her
search for "ambients" or suitable media. Thus, we agree with
the examiner that it would have required "undue"
experimentation by the skilled routineer to find media other
than nitrogen or water which would suit appellants' purpose in
claim 10 for "preventing said photoacid from being
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Application 08/135,324
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neutralized."
Factors to be considered in determining whether a
disclosure would require "undue" experimentation include (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 the
routineer in the art, (7) the predictability or lack thereof
in the art, and (8) the breadth of the claims. In re Wands,
858 F.2d 731, 737, 8 USPQ2d 1400, 1404 (Fed. Cir. 1988).
Our review of appellants' specification reveals
scant little information concerning criteria for selecting
other "ambients". Appellants describe at page 9, lines 19
through 20, the problem which their invention addresses.
Therein, appellants state that:
If the wafer is left in an open air
environment, the acid neutralizes,
such that it is not an effective
catalyst.
At page 3 of the specification, appellants state that:
The present invention overcomes this problem by
avoiding the effects of the clean room ambient
during the post exposure period.
Subsequently, appellants disclose at page 5, lines 5 and 6
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that:
After exposure, the wafer is maintained in an inert
medium to ensure that the latent image remains
stable.
Lines 10 through 15 of page 5 inform us that:
In one embodiment, the inert medium can be nitrogen
gas. In another embodiment, the wafer can be
maintained in water. In another embodiment, the
wafer can be maintained in nitrogen during the
exposure of the wafer. Finally, the nitrogen or
other inert atmospheric conditions can also be
employed to regenerate the surface of the latent
image after it has been subjected to the normal
clean room ambient.
At page 10, line 5 through page 11, line 9,
appellants discuss several embodiments of their invention.
Specifically, after a series of conventional, prior art
processing steps but before post exposure baking appellants
disclose that:
the water cassette used to hold the
wafers during lithography process 100
could be modified to provide an inert
gas ambient for the wafers after
exposure. (page 5, lines 5 through 8)
It is also disclosed that:
In the currently preferred embodiment
the wafer ambient is the inert gas
nitrogen. (page 5, lines 10 and 11)
As an alternative, the wafers may be stored in water rather
than an inert gas (page 5, lines 14 and 15). Or, the wafer
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Application 08/135,324
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handling portion of the apparatus could be enclosed and
nitrogen flowed inside the chamber (page 5, lines 16 through
20). Finally, the entire exposure process could be conducted
in a nitrogen ambient instead of air, which is conventional
(page 5, line 21 through page 6, line 3).
The above referenced portions of appellants'
disclosure are the entire disclosure relevant to the issue
before us. We reiterate that we find little or no guidance
beyond the two, specifically enumerated expedients, which
would aid the ordinarily skilled routineer in selecting other
suitable media for performing appellants' process. We agree
with examiner's implicit conclusion that it would have
required undue experimentation by the person of ordinary skill
to practice the claimed invention. While appellants argue
that "the use of chemical ambients in conjunction with the
'preventing' step does not involve complex chemical
reactions", the issue before us concerns the scope of the step
of preventing neutralization of the photoacid not the use of
"chemical ambients".
We find no guidance in appellants' disclosure nor
have appellants directed us to any, which would serve as a
starting point for the routineer to even begin a search for
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Application 08/135,324
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other "ambients". Nothing save the ability of the "ambient"
or media to prevent neutralization of the photoacids is
described. There are no working examples in the
specification. Nevertheless, the nature of the neutralization
and the mechanism by which appellants prevent or inhibit
neutralization is not described. We recognize that an
applicant for patent need not understand or even know how the
claimed invention functions. But, in this scenario, we find
understanding the mechanism of how nitrogen, a gas present in
approximately 80 volume percent in ambient air, or water, a
liquid, each function to inhibit neutralization would have
presented the ordinarily skilled person a starting point for
selecting other candidates for preventing neutralization.
Moreover, appellants state in their specification
that they are preventing neutralization of the photoacids
caused by some undisclosed, undescribed agent or agents in the
ambient atmosphere of a "clean" room after generation of
photoacids in the resist but before the post etching baking.
Appellants have conceded in their brief that the routineer
would be left to a trial and error technique in order to find
other "ambients" capable of preventing neutralization of the
photoacids. Additionally, there is no disclosure in the
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Application 08/135,324
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specification concerning the nature of photoacids generated by
the irradiation step. Such information would have been useful
to a person of ordinary skill seeking to find agents to
prevent neutralization of the photoacids.
In reaching our decision, we have not overlooked the
colloquy between the examiner and appellants concerning the
meaning of the terminology "inert medium". However, whether
the meaning of a term in a claim is definite or precise is an
issue under 35 U.S.C. § 112, second paragraph, and we are not
presented with any rejection of the claims under said statute.
The issue which was presented for our review and which we have
decided concerned the scope of the language "preventing said
photoacid from being neutralized" and the corresponding scope
of appellants' enabling disclosure.
The decision of the examiner is AFFIRMED.
No time period for taking any subsequent action in
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connection with this appeal may be extended under 37 C.F.R. §
1.136(a).
AFFIRMED
MARC L. CAROFF )
Administrative Patent Judge)
)
)
)

ANDREW H. METZ )
Administrative Patent Judge)
) BOARD OF
PATENT
) APPEALS AND
)
INTERFERENCES
ADRIENE LEPIANE HANLON )
Administrative Patent Judge)

AHM/gjh
Appeal No. 95-3936
Application 08/135,324
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