Ex Parte FU et al

Board of Patent Appeals and Interferences

Apr 30, 2003

08854008 (B.P.A.I. Apr. 30, 2003)

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not written for publication and is not binding precedent of the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. 13
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte JIANMING FU, PEIJUN DING, and ZHENG XU
__________
Appeal No. 2001-1812
Application No. 08/854,008
__________
ON BRIEF
__________
Before GARRIS, OWENS, and KRATZ, Administrative Patent Judges.
GARRIS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on an appeal which involves claims 1-16
and 18-28. These are all of the claims remaining in the
application.
The subject matter on appeal relates to a sustained self-
sputtering apparatus and method. In one embodiment, the
apparatus and method include a biasable grid positioned between
Appeal No. 2001-1812
Application No. 08/854,008
2
the target and support. According to the appellants, the
presence of this grid increases plasma density and thereby
promotes sustained self-sputtering. In another embodiment, a
sputtering method is claimed which does not require the presence
of a grid but which requires holding an interior of the
sputtering chamber at a pressure of less than 1×10-6Torr and
applying sufficient electrical power to the target to self-
sustain a target plasma. This appealed subject matter is
adequately illustrated by independent apparatus claim 4 and
independent method claim 27 which read as follows:
4. A sustained self-sputtering apparatus, comprising:
a vacuum chamber including a support for a substrate;
a sputtering target in said camber facing said support;
a magnet assembly positioned on a side of said target
opposite a central portion of said chamber;
a first power supply electrically biasing said target with
respect to a portion of said chamber and capable of supporting a
self-sustained plasma of ions sputtered from said target;
a grid positioned between said target and support and
biasable at an electrical potential; and
a second power supply electrically biasing said support with
respect to said grid.
27. A sputtering method in a sputtering chamber comprising a
target, a magnet assembly on a side of said target, and a
substrate support for supporting a substrate, said method
comprising the steps of:
Appeal No. 2001-1812
Application No. 08/854,008
1 We refer to these Japanese references with the respective
names used by the examiner, and our understanding of these
references is based upon the respective English translations
thereof.
3
igniting a plasma in said chamber adjacent to said target;
after said plasma has been ignited, holding an interior of
said chamber at a pressure of less than 1×10-6Torr and applying
sufficient electrical power to said target to self-sustain a
target plasma in a volume of said chamber adjacent to said magnet
assembly; and
moving said magnet assembly over said side of said target,
wherein said magnet assembly has an area between magnet portions
thereof of no more than 25% of an area of said target.
The references set forth below are relied upon by the
examiner as evidence of obviousness:
Mikalesen et al. (Mikalesen) 4,824,544 Apr. 25, 1989
Demaray et al. (Demaray) 5,330,628 Jul. 19, 1994
Hazuki (JP) 61-1747251 Aug. 6, 1986
Tokuda Seisakusho (JP) 64-282911 Jan. 31, 1989
Tokyo Electron (JP) 2-2982631 Dec. 10, 1990
Ogawa et al. (Ogawa)(JP) 3-1404671 Jun. 14, 1991
Naoe (JP) 3-2409441 Oct. 28, 1991
Igarashi (JP) 5-1952131 Aug. 3, 1993
Shiraishi (JP) 5-3114191 Nov. 22, 1993
Asamaki (JP) 7-1268441 May 16, 1995
Posadowski et al. (Posadowski), “Sustained self-sputtering using
a direct current magnetron source,” J. Vac. Sci. Technol A, Vol.
11, No. 6, pp. 2980-2984 (1993).
Asamaki et al. (Asamaki), “Copper Self-Sputtering by Planar
Magnetron,” Jpn. J. Appl. Phys., Vol. 33, pt. 1, No. 5A,
pp. 2500-2503 (1994).
Appeal No. 2001-1812
Application No. 08/854,008
4
Claims 1, 2, 4, 5, 7, 19, 20 and 23-25 are rejected under 35
U.S.C. § 103(a) as being unpatentable over Shiraishi or Hazuki or
Igarashi or Mikalesen in view of Demaray, the Asamaki article and
the Posadowski article; the remaining claims on appeal are
correspondingly rejected over these references and further in
view of various combinations of the other previously-listed
references relied upon by the examiner.
We refer to the brief and to the answer for a complete
discussion of the contrary viewpoints expressed by the appellants
and by the examiner concerning the above noted rejections.
OPINION
For the reasons set forth below, we cannot sustain any of
the rejections advanced by the examiner on this appeal except for
the rejections of independent claim 27 and of claim 28 which
depends therefrom.
Claims 1-16 and 18-26 are directed to a sustained self-
sputtering apparatus or method which includes a biasable grid
positioned between the target and support. With respect to these
claims, it is the examiner’s basic position that each of the
“primary” references to Shiraishi or Hazuki or Igarashi or
Mikalesen discloses an apparatus which is not sustained self-
sputtering as here claimed but which includes a biasable grid
Appeal No. 2001-1812
Application No. 08/854,008
5
positioned between the target and support. According to the
examiner, the Asamaki article and the Posadowski article supply
the aforementioned sustained self-sputtering deficiency of the
primary references, and “it would be [sic, would have been]
obvious to modify the primary references by utilizing self-
sputtering conditions of Asamaki . . . and Posadowski . . . since
it allows for good filling of a contact hole” (answer, page 15).
More specifically, the examiner states:
it is agreed that the primary references do not suggest
the conditions required for generating sustained self
sputtering but the secondary references of Asamaki ...
and Posadowski ... teach the conditions needed for
sustained self sputtering with the benefit being that
contact holes can be filled uniformly which the primary
references also recognize as important [answer, page
16].
The examiner’s position is not well taken.
As correctly argued by the appellants and seemingly
appreciated by the examiner, the conventional sputtering
technique of the respective primary references is distinct from
the sustained self-sputtering technique of Asamaki and
Posadowski. Contrary to the examiner’s belief, it would not have
been obvious to combine these techniques in the fashion proposed
by the examiner simply because the primary and secondary
references disclose common desideratum such as the effective
filling of contact holes. As properly indicated in the brief,
Appeal No. 2001-1812
Application No. 08/854,008
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the applied prior art contains no teaching or suggestion that the
respective techniques of the primary and secondary references are
individually insufficient to achieve the desired results or that
the achievement of such results would have been enhanced by
combining these techniques in the manner proposed by the
examiner. Indeed, there is merit in the appellants’ argument
that the sustained self-sputtering techniques of Asamaki and
Posadowski do not exhibit the problems which are taught by at
least some of the primary references as being solved via the
“grids” disclosed therein.
For example, the control plates or “grid” of Shiraishi and
the sustained self-sputtering technique of Asamaki both direct
the flow of sputtering atoms so that contact holes in substrates
are effectively filled. Based on the disclosures of these
references, an artisan with ordinary skill would have considered
Shiraishi’s “grid” and Asamaki’s self-sputtering technique to be
individually effective in obtaining this desired result and thus
would not have considered combining these features as the
examiner urges because such a combination seemingly would be
redundant. Similarly, the mesh type control electrode or “grid”
of Hazuki performs the function of capturing secondary electrons
to prevent them from reaching and adversely affecting the
Appeal No. 2001-1812
Application No. 08/854,008
7
substrate. There is nothing in either Asamaki or Posadowski
which reflects that the self-sputtering techniques thereof suffer
from any such problem involving “secondary electrons.” It
follows that no basis exists for combining the teachings of
Hazuki with the teachings of Asamaki and Posadowski.
In addition to the foregoing, we find nothing and the
examiner points to nothing in the applied prior art which would
have given an artisan a reasonable expectation that the
combination proposed by the examiner would have been successful.
For all we know, based on the applied reference evidence, the
primary reference feature of a biasable grid positioned between
the target and substrate would have been incompatible with the
secondary reference feature of a sustained self-sputtering
technique. That is, an artisan having read the applied
references might have as easily expected the presence of such a
grid to inhibit a self-sputtering operation rather than enhance
it as taught by the appellants. We here remind the examiner that
obviousness under section 103 requires not only a suggestion to
combine the applied reference teachings but also a reasonable
expectation that such a combination would be successful. See In
re O’Farrell, 853 F.2d 894, 903-04, 7 UPSQ2d 1673, 1680-81 (Fed.
Cir. 1988).
Appeal No. 2001-1812
Application No. 08/854,008
8
For the reasons set forth above, we cannot sustain any of
the examiner’s section 103 rejections of claims 1-16 and 18-26.
We reach a different conclusion regarding the section 103
rejections of claims 27 and 28. Concerning these rejections, the
only argument advanced by the appellants is that “Claim 27 . . .
recites a microTorr of pressure for sustained self-sputtering”
and that “the [applied prior] art does not teach such a low
pressure, and hence this claim must be held allowable” (brief,
page 12). As properly indicated by the examiner, however, the
abstract of Asamaki expressly teaches that “self-sputtering of
copper is performed in a wide pressure range of 10-2 Pa to 10-4
Pa.” The appellants’ apparent belief that Asamaki’s lower most
pressure of 10-4 Pa (which correspond to 0.75×10-6Torr and thus
falls within the here claimed range) relates to reactor
capability rather than operational pressure is not well taken
since it is contrary to the previously quoted, express disclosure
of Asamaki. In any event, if nothing else, Asamaki evinces that
the parameter of pressure constitutes an art-recognized variable
in a sustained self-sputtering operation, and it is generally
considered that it would have been obvious for an artisan to
determine workable or even optimum values for such an art-
recognized, result-effective variable. In re Woodruff, 919
Appeal No. 2001-1812
Application No. 08/854,008
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F.2d 1575, 1578, 16 USPQ2d 1934, 1936-37 (Fed. Cir. 1990); In re
Boesch, 617 F.2d 272, 276, 205 USPQ 215, 219 (CCPA 1980); In re
Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Under these circumstances, we will sustain the examiner’s
section 103 rejections of independent claim 27 and of nonargued
dependent claim 28.
The decision of the examiner is affirmed-in-part.
No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).
AFFIRMED-IN-PART
Bradley R. Garris )
Administrative Patent Judge )
)
)
)
Terry J. Owens ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
Peter F. Kratz )
Administrative Patent Judge )
BRG:tdl
Appeal No. 2001-1812
Application No. 08/854,008
10
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