Ex Parte Chen et al

Board of Patent Appeals and Interferences

Jan 9, 2004

09876447 (B.P.A.I. Jan. 9, 2004)

1
The opinion in support of the decision being entered today was
not written for publication and is not binding precedent of the
Board.
Paper No. 11
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte YING-HO CHEN, WEN-CHIH CHIOU,
CHENG-CHUNG LIN, and SYUN-MING JANG
__________
Appeal No. 2004-0085
Application No. 09/876,447
__________
ON BRIEF
__________
Before GARRIS, PAK, and DELMENDO, Administrative Patent Judges.
GARRIS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on an appeal from the final rejection of
claims 1 and 3-18 which are all of the claims in the application.
The subject matter on appeal relates to a method and
apparatus for in-situ cleaning of a pad and a wafer during
chemical mechanical polishing wherein an acid-containing solution
comprising water and an acid selected from the group consisting
of citric acid, HCOOH, CH3COOH, HNO3, H2SO4, and HF is dispensed
Appeal No. 2004-0085
Application No. 09/876,447
2
onto the top surface of the polishing pad while the pad and wafer
are being rotated. This appealed subject matter is adequately
illustrated by independent claim 1 which reads as follows:
1. A method for in-situ cleaning a pad and a wafer during
chemical mechanical polishing comprising the steps of:
rotating a wafer and a polishing pad in opposite directions;
conducting a chemical mechanical polishing process on a
wafer surface;
stopping the dispensing of a slurry solution onto a top
surface of said polishing pad;
mixing an acid-containing solution from water and an acid
selected from the group consisting of citric acid, HCOOH,
CH3COOH, HNO3, H2SO4 and HF;
dispensing said acid-containing solution onto said top
surface of said polishing pad while said wafer and said pad are
being rotated.
The references relied on by the examiner are:
Koos et al. (Koos) 5,934,980 Aug. 10, 1999
Laursen et al. (Laursen) 6,387,188 B1 May 14, 2002
(filed Mar. 3, 1999)
Claims 1, 3-7 and 9-18 are rejected under 35 U.S.C. §102(b)
as being anticipated by Koos.
Claim 8 is rejected under 35 U.S.C. §103(a) as being
unpatentable over Koos in view of Laursen.
We refer to the Brief and to the Answer and final Office
action (Paper No. 4) for a complete exposition of the opposing
viewpoints expressed by the appellants and by the examiner
concerning the above noted rejections.
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Application No. 09/876,447
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The appellants have separately grouped and argued the
appealed claims in accordance with the manner in which they have
been rejected (see page 5 of the Brief).
OPINION
For the reasons set forth below, we will sustain each of
these rejections.
As explained by the examiner in the Answer, the Koos
reference discloses both a method and an apparatus for in-situ
cleaning of a pad and wafer during chemical mechanical polishing
wherein an acid-containing solution is dispensed onto the top
surface of the polishing pad (see Answer, page 3-4). The
examiner describes in detail how the Koos reference discloses
every element of claims 1, 3-7 and 9-18, including the steps of
“mixing an acid-containing solution from water and an acid
selected from the group consisting of HF (hydrofluoric acid)” and
“dispensing the acid-containing solution onto the top surface of
the polishing pad 16 while the wafer 12 and the pad 16 are being
rotated” (see Answer, page 3).
The appellants respond on page 8 of the Brief that the
solution disclosed in Koos and relied upon by the examiner in the
final rejection “contains both a weak acid and a weak base and,
wherein the only example of a weak acid is shown as containing 20
parts of ammonium fluoride and 1 part hydrofluoric acid, which is
Appeal No. 2004-0085
Application No. 09/876,447
1 It should be noted that appellants make no specific arguments directed at
the rejection of the apparatus claims, but rather focus on differentiating the
method claims from the prior art. None of the arguments presented by the
appellants in the Brief are persuasive or even relevant in overcoming the
examiner’s §102(b) rejection with respect to the apparatus claims.
Significantly, the appellants do not identify and we do not find structural
elements present in the independent apparatus claim which differentiate the
claimed invention from the apparatus disclosed in Koos.
4
clearly not a water solution of HF” (emphasis in original). The
appellants also contend after describing the invention of Koos
that “[t]he present invention, to the contrary, teaches and
claims a method for in-situ cleaning a pad and a wafer” (Breif,
page7; emphasis in original)1.
In response to these arguments, the examiner replies that
the Koos reference “clearly disclose[s] a water solution of HF”
and further quotes the reference as teaching a solution
comprising “about 20 parts by volume of ammonium fluoride
solution (80 weight percent in water) and 1 part hydrofluoric
acid (49 weight percent in water)” (see Answer, page 5).
We agree with the examiner that the Koos reference
discloses a water solution of HF. The Koos reference, at column
6, lines 63-67, discloses a buffer solution wherein the
hydrofluoric acid is 49 weight percent in water. Thus, 51
percent of the total weight of the 1 part hydrofluoric acid is
attributable to water and 49 percent of the total weight of the 1
part hydrofluoric acid is attributable to the hydrofluoric acid.
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Application No. 09/876,447
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The solution disclosed by Koos qualifies as a water solution of
HF.
We further note that independent claims 1 and 11 (as well as
all of the dependent claims) are considered “open” claims because
they include the term “comprising” in the preamble. Therefore,
interpretation of all of the claims under appeal is not limited
to only those elements specifically recited. The term
“comprises” permits the inclusion of other (i.e., unrecited)
steps, elements, or materials. In re Baxter, 656 F.2d 679, 686,
210 USPQ 795, 802. Thus, the fact that the solution disclosed in
Koos includes a weak acid and a weak base does not preclude the
reference from reading on the claim recitation of an “acid-
containing solution from water and an acid selected from the
group consisting of citric acid, HCOOH, CH3COOH, HNO3, H2SO4, and
HF” (i.e., because the claims are “open” claims).
Finally, with respect to appellants’ argument that Koos does
not teach a method of cleaning a pad and a wafer, we point to the
abstract as well as Figure 3 of the Koos reference for support
that Koos teaches a method of cleaning a pad and a wafer. The
abstract states in part that “[a] diluting solution is then
applied to the polishing pad to remove slurry of the first CMP
step.” Removal of slurry constitutes cleaning of a pad and a
wafer. Further, element 44 of Figure 3 contains the caption
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Application No. 09/876,447
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“CLEAN THE POLISHING SURFACE OF THE POLISHING PAD.” It follows
that Figure 3 also provides evidence that Koos discloses a method
of cleaning a pad and a wafer.
With respect to the §103(a) rejection of dependent claim 8,
the examiner cites Laursen to support an obviousness conclusion
with respect to using citric acid in formulating Koos’ acid-
containing solution. Appellants broadly respond that Laursen
“does not lend any additional weight in a §103(a) rejection of
the present in-situ cleaning method” and maintain that they have
“clearly shown above that the primary reference of Koos et al
does not teach a method for in-situ cleaning of a pad and a wafer
during CMP, including the step of mixing an acid-containing
solution from water and an acid selected from the group
consisting of citric acid, HCOOH, CH3COOH, HNO3, H2SO4 and HF”
(Brief, page 9). The examiner replies on pages 5 through 6 of
the Answer that Laursen discloses the use of citric acid in an
acid-containing solution and that “it would have been obvious to
one having ordinary skill in the art at the time the invention
was made to use citric acid as disclosed by Laursen et al in
place of hydrofluoric acid (HF) with the method and apparatus of
Koos et al in order to remove copper-containing debris from a
surface of a polishing pad.”
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Application No. 09/876,447
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We agree with the examiner’s conclusion of obviousness for
the reasons expressed in the Answer. The appellants have given
no basis for a contrary conclusion other than their argument that
the primary reference is deficient and that Laursen lends no
additional weight in the §103(a) rejection. As we have already
found the Koos primary reference is not deficient with respect to
the §102(b) rejection, we cannot agree with the appellants. We
therefore sustain the §103(a) rejection of claim 8 as being
unpatentable over Koos in view of Laursen.
SUMMARY
The decision of the Examiner is affirmed.
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Application No. 09/876,447
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No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).
AFFIRMED
Bradley R. Garris )
Administrative Patent Judge )
)
)
)
Chung K. Pak ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
Romulo H. Delmendo )
Administrative Patent Judge )
BRG:tdl
Appeal No. 2004-0085
Application No. 09/876,447
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