Ex Parte Shue et al

Board of Patent Appeals and Interferences

Jun 30, 2004

09489970 (B.P.A.I. Jun. 30, 2004)

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written for publication and is not binding precedent of the Board.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. 20
UNITED STATES PATENT AND TRADEMARK OFFICE
____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________
Ex parte SHAU-LIN SHUE and MEI-YUN WANG
____________
Appeal No. 2003-1971
Application No. 09/489,970
____________
ON BRIEF
____________
Before HAIRSTON, FLEMING, and LEVY, Administrative Patent Judges.
FLEMING, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of
claims 1, 2, 9, 12 and 13. Claims 3-8, 10 and 11 stand objected
to for being dependent on a rejected claim. Claim 14 has been
allowed. Thus, the only claims before us for our consideration
are claims 1, 2, 9, 12 and 13.
Invention
The invention relates to the fabrication of integrated
circuit devices. In particular, the invention relates to a
method of forming salicided gate electrodes whereby no danger
exists of having an electrical short between the gate contact and
Appeal No. 2003-1971
Application No. 09/489,970
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the contacts for the source and drain regions. See page 1 of
Appellants' specification.
Referring now to specifically Figure 4, there is shown a
cross section of a partially completed gate electrode 40 on a
substrate 10. See page 15 of Appellants' specification. Figure
5 shows a cross section of a gate electrode 40 whereby gate
spacers of oxide (42) have been created. The layer 42 forms the
first layer of a double layer gate spacer on the side walls of
the partially completed gate of electrode 40. See page 16 of
Appellants' specification. Figure 6 shows a cross section of the
gate electrode after the second layer 44 of silicon nitride has
been created to form the second layer of the gate spacers. See
pages 17 and 18 of Appellants' specification. Figure 7 shows a
cross section of the gate electrode after the source 52 and drain
54 are implanted into the surface of substrate 10. See page 19
of Appellants' specification. Figure 8 shows a cross section of
the gate electrode after the layer 46 of the cobalt has been
deposited over the surface of the structure 40. See page 19 of
Appellants' specification. Figure 9 shows the siliciding of the
layer of cobalt creating reacted layers 56, 58 and 60 and
unreacted layer 46 of cobalt. See page 20 of Appellants'
specification. Figure 10 shows a cross section of the gate
Appeal No. 2003-1971
Application No. 09/489,970
3
structure of the invention after the removal of the unreacted
cobalt. See page 21 of Appellants' specification. Figure 11
shows a cross section of the gate structure after the removal of
the outer gate spacer layer 44. See pages 21 and 22 of
Appellants' specification.
Independent claim 1 is representative of Appellants' claimed
invention and is reproduced as follows:
1. A method for manufacturing salicided regions for electrical
contact to a semiconductor device, comprising the sequential
steps of:
providing a silicon semiconductor substrate whereby said
substrate has been provided with a semiconductor device whereby
said semiconductor device is a partially completed gate electrode
structure;
creating double layered gate spacers on the sidewalls of
said partially completed gate electrode structure said double
layered gate spacers containing an inner gate spacer comprising
oxide layer that is immediately adjacent to and overlying the
sidewalls of said partially completed gate electrode structure
and an outer gate spacer layer comprising silicon nitride that
overlays said inner layer thereby creating an intermediately
completed gate electrode structure;
performing source and drain implants into the surface of
said substrate whereby said source and drain implants are self-
aligned with said intermediately completed gate electrode
structure;
depositing a layer of cobalt over the surface of said
substrate thereby including the surface of said intermediately
completed gate electrode structure;
saliciding said layer of cobalt thereby creating reacted and
unreacted layers of cobalt on the surface of said substrate
Appeal No. 2003-1971
Application No. 09/489,970
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thereby including the surface of said intermediately completed
gate electrode structure;
removing said unreacted cobalt from the surface of said
substrate thereby including the surface of said intermediately
completed gate electrode structure; and
removing said outer gate spacer layer from said
intermediately completed gate electrode structure, using a warm
H3PO4 based etchant, thereby creating a gate electrode structure.
References
The references relied on by the Examiner are as follows:
Tsai et al. (Tsai '024) 5,668,024 Sep. 16, 1997
Tsai et al. (Tsai '890) 5,851,890 Dec. 22, 1998
DeBoer et al. (DeBoer) 6,258,729 Jul. 10, 2001
Rejection at Issue
Claims 1, 2, 9, 12 and 13 stand rejected under 35 U.S.C.
§ 103 as being unpatentable over Tsai '890, Tsai '024 and
DeBoer '729.
OPINION
With full consideration being given to the subject matter on
appeal, the Examiner's rejection and arguments of Appellants and
Examiner, for the reasons stated infra, we affirm the Examiner's
rejection of claims 1, 2, 9, 12 and 13 under 35 U.S.C. § 103.
At the outset, we note that Appellants state on page 11 of
the brief that claim 1 and dependent claims 2-13 form a first
group of claims. 37 CFR § 1.192 (c)(7) (July 1, 2002) as
Appeal No. 2003-1971
Application No. 09/489,970
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amended at 62 Fed. Reg. 53196 (October 10, 1997), which was
controlling at the time of Appellants filing the brief, states:
For each ground of rejection which [A]ppellants contest
and which applies to a group of two or more claims, the
Board shall select a single claim from the group and
shall decide the appeal as to the ground of rejection
on the basis of that claim alone unless a statement is
included that the claims of the group do not stand or
fall together and, in the argument under paragraph
(c)(8) of this section, Appellants explains why the
claims of the group are believed to be separately
patentable. Merely pointing out differences in what
the claims cover is not an argument as to why the
claims are separately patentable.
We will, thereby, consider Appellants' claims as standing or
falling together and we will treat claim 1 as a representative
claim of that group. See In re McDaniel, 293 F.3d 1379, 1383,
63 USPQ2d 1462, 1465 (Fed. Cir. 2002) ("If the brief fails to
meet either requirement [of 37 CFR § 1.192(c)(7)], the Board is
free to select a single claim from each group of claims subject
to a common ground of rejection as representative of all claims
in that group and to decide the appeal of that rejection based
solely on the selected representative claim.") See also, In re
Watts, 354 F.3d 1362, 1368, 69 USPQ2d 1453, 1458 (Fed. Cir.
2004).
In rejecting claims under 35 U.S.C. § 103, the Examiner
bears the initial burden of establishing a prima facie case of
Appeal No. 2003-1971
Application No. 09/489,970
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obviousness. In re Oetiker, 977 F.2d 1443, 1445, 24 USPQ2d 1443,
1444 (Fed. Cir. 1992). See also In re Piasecki, 745 F.2d 1468,
1472, 223 USPQ 785, 788 (Fed. Cir. 1984). The Examiner can
satisfy this burden by showing that some objective teaching in
the prior art or knowledge generally available to one of ordinary
skill in the art suggests the claimed subject matter. In re
Fine, 837 F.2d 1071, 1074, 5 USPQ2d 1596, 1598 (Fed. Cir. 1988).
Only if this initial burden is met does the burden of coming
forward with evidence or argument shift to the Appellants.
Oetiker, 977 F.2d at 1445, 24 USPQ2d at 1444. See also Piasecki,
745 F.2d at 1472, 223 USPQ at 788.
An obviousness analysis commences with a review and
consideration of all the pertinent evidence and arguments. "In
reviewing the [E]xaminer's decision on appeal, the Board must
necessarily weigh all of the evidence and argument." Oetiker,
977 F.2d at 1445, 24 USPQ2d at 1444. "[T]he Board must not only
assure that the requisite findings are made, based on evidence of
record, but must also explain the reasoning by which the findings
are deemed to support the agency's conclusion." In re Lee,
Appeal No. 2003-1971
Application No. 09/489,970
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277 F.3d 1338, 1344, 61 USPQ2d 1430, 1434 (Fed. Cir. 2002). With
these principles in mind, we commence review of the pertinent
evidence and arguments of Appellants and Examiner.
Appellants point out that claim 1 recites that the oxide is
used for a first gate spacer and that silicon nitride is used for
a second gate spacer. Appellants argue that Tsai '890 claims a
composite spacer comprising silicide which has no commonality
with the instant invention.
The question is not what Tsai '890 claims but instead what
Tsai '890 teaches. Tsai '890 teaches a double layer gate spacer
on the sidewalls of the partially completed gate electrode
structure, said double layer gate spacer containing an inner gate
spacer 50 comprising an oxide layer that is immediately adjacent
to and overlying the sidewalls of the partially completed gate
electrode structure and outer gate spacer layers 60 and 62
comprising silicon nitride that overlays said inner layer thereby
creating an intermediate completed gate electrode structure as
recited in Appellants' claim 1. See Tsai '890, column 4, line 50
through column 5, line 17. Therefore, Tsai '890 does teach that
the oxide is used for a first gate spacer and that silicon
nitride is used for a second gate spacer.
Appeal No. 2003-1971
Application No. 09/489,970
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Appellants concede that Tsai '024 does teach the removal of
the second spacer. However, Appellants argue that the process
used is prone to damaging the formed silicide cobalt.
While this court indeed warns against employing hindsight,
its counsel is just that--a warning. That warning does not
provide a rule of law that express, written motivation to combine
must appear in prior art references before a finding of
obviousness. Stated differently, this court has consistently
stated that a court or examiner may find a motivation to combine
prior art references in the nature of the problem to be solved.
Ruiz v. A.B. Chance Co., 357 F.3d 1270, 1276, 69 USPQ2d 1686,
1690 (Fed. Cir. 2004). Also see Pro-Mold & Tool Co. v. Great
Lakes Plastics, Inc., 75 F.3d 1568, 1573, 37 USPQ2d 1626, 1630
(Fed. Cir. 1996); Display Techs. Inc. v. Paul Flum Ideas, Inc.,
282 F.3d 1340, 1346-47 (Fed. Cir. 2002); In re Huang, 100 F.3d
135, 139, 40 USPQ2d 1685, 1689 (Fed. Cir. 1996).
Upon our review of Tsai '024, we fail to find any teaching
that the removal process disclosed would damage the silicide
cobalt layer. Furthermore, Tsai '024 suggests that silicon
nitride can be removed with hot phosphoric acid. See Tsai '024,
column 4, lines 2-4. DeBoer also teaches the use of an APM
Appeal No. 2003-1971
Application No. 09/489,970
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solution as well as a hot phosphoric solution to remove
insulating layers. See DeBoer, column 11, lines 25-40.
Therefore, one of ordinary skill in the art would have had before
him these teachings that would lead him to use a hot phosphoric
solution to remove the silicon nitride spacer as claimed.
Appellants have not made any other arguments as to the
claims. 37 CFR § 1.192(a) states:
Appellants must, within two months from the date of the
notice of appeal under § 1.191 or within the time
allowed for reply to the action from which the appeal
was taken, if such time is later, file a brief in
triplicate. The brief must be accompanied by the fee
set forth in § 1.17(c) and must set forth the
authorities and arguments on which [A]ppellants will
rely to maintain the appeal. Any arguments or
authorities not included in the brief will be refused
consideration by the Board of Patent Appeals and
Interferences, unless good cause is shown.

Thus, 37 CFR § 1.192 provides that only the arguments made by
Appellants in the brief will be considered and that failure to
make an argument constitutes a waiver on that particular point.
Support for this rule has been demonstrated by our reviewing
court in In re Berger, 279 F.3d 975, 984, 61 USPQ2d 1523, 1528-29
(Fed. Cir. 2002), wherein the Federal Circuit Court stated that
because the Appellants did not contest the merits of the
rejections in the brief to the Federal Circuit Court, the issue
is waived.
Appeal No. 2003-1971
Application No. 09/489,970
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In view of the foregoing, we have sustained the Examiner's
rejection of claims l, 2, 9, 12 and 13 under 35 U.S.C. § 103.
No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).
AFFIRMED
KENNETH W. HAIRSTON )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
MICHAEL R. FLEMING ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
STUART S. LEVY )
Administrative Patent Judge )
MRF/lbg
Appeal No. 2003-1971
Application No. 09/489,970
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