Ex Parte Akram

Board of Patent Appeals and Interferences

Jul 27, 2005

10209004 (B.P.A.I. Jul. 27, 2005)

1 The appellant states (specification, page 15, lines 20-25): “As used
herein to define the present invention, the term ‘nodular shape’ means a
structure having a finite cross section which includes a curved or partially
curved cross section, and a partially square or rectangular cross section
having curved corners, partially curved corners or faceted corners and having
a width equal to or greater than the width of the contact 64 or 114. The term
‘nodular shape’ does not incorporate either a square cross section or a
rectangular cross section.”
The opinion in support of the decision being entered
today was not written for publication and is not
binding precedent of the Board.
UNITED STATES PATENT AND TRADEMARK OFFICE
____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________
Ex parte SALMAN AKRAM
____________
Appeal No. 2005-1894
Application No. 10/209,004
____________
ON BRIEF
____________
Before OWENS, RUGGIERO, and DIXON, Administrative Patent Judges.
OWENS, Administrative Patent Judge.
DECISION ON APPEAL
This appeal is from a rejection of claims 2 and 4-11.
THE INVENTION
The appellants claim a method for forming an electrode
having a nodular shape,1 and claim methods for forming a
capacitor, a semiconductor device, a memory array and a wafer
that include the method for forming the electrode. Claim 2,
Appeal No. 2005-1894
Application No. 10/209,004
2 Citations herein to Hosaka are to the English translation thereof
which is of record.
2
which claims the method for forming the electrode, is
illustrative:
2. A method for forming an electrode comprising:
forming an insulating layer;
forming a contact in said insulating layer;
forming an electrode layer on said insulating layer and
on said contact;
etching said electrode layer utilizing a dry etch; and
etching said electrode layer utilizing a wet etch to
form an electrode having a nodular shape.
THE REFERENCES
Sandhu et al. 5,381,302 Jan. 10, 1995
(Sandhu)
Hosaka2 62-115767 May 27, 1987
(Japanese Kokai)
THE REJECTION
Claims 2 and 4-11 stand rejected as being unpatentable over
Sandhu in view of Hosaka.
OPINION
We affirm the aforementioned rejection.
The appellant states that the claims stand or fall in three
groups: 1) claims 2, 4-6 and 10; 2) claims 7 and 9; and
Appeal No. 2005-1894
Application No. 10/209,004
3
3) claims 8 and 11 (brief, page 4). We therefore limit our
discussion to one claim in each group, i.e., claims 2, 7 and 8.
See In re Ochiai, 71 F.3d 1565, 1566 n.2, 37 USPQ2d 1127, 1129
n.2 (Fed. Cir. 1995); 37 CFR § 1.192(c)(7)(1997).
Claim 1
Sandhu discloses a method for forming a storage node
electrode of a capacitor in a dynamic random access memory (DRAM)
device, comprising forming an insulating layer (40; figure 3),
forming a contact (65) in the insulating layer (figure 5),
forming an electrode layer (85) on the insulating layer and the
contact (figure 11A), and etching the electrode layer using a dry
etch (col. 6, lines 60-64). Sandhu does not disclose etching the
electrode layer using a wet etch to form the electrode into a
nodular shape.
Hosaka etches the lower electrode of a nonvolatile memory or
DRAM using a dry etch and then a wet etch to remove the surface
roughness and distortions on the lower electrode and to round the
corner portions of the lower electrode’s side surface, thereby
preventing degradation of the quality of an insulating film
formed on the lower electrode and obtaining good electrical
characteristics (page 3).
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Application No. 10/209,004
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The appellant argues that Sandhu would not have suggested
eliminating surface roughness or sharp corners on a platinum
electrode to provide a smooth topology (brief, page 6; reply
brief, page 3). That argument is not well taken because the
appellants are attacking the reference individually when the
rejection is based upon a combination of references. See In re
Keller, 642 F.2d 413, 426, 208 USPQ 871, 882 (CCPA 1981); In re
Young, 403 F.2d 754, 757-58, 159 USPQ 725, 728 (CCPA 1968).
Hosaka is relied upon by the examiner for a suggestion to dry
etch and then wet etch Sandhu’s lower electrode to remove surface
roughness and distortions and to form the lower electrode into a
nodular shape by rounding the corner portions of the lower
electrode’s side surface (answer, page 4).
The appellant argues that neither Sandhu nor Hosaka
discloses a desire to reduce current leakage (brief, pages 6-7;
reply brief, page 2). To establish a prima facie case of
obviousness, references need not be combined for the purpose of
solving the problem solved by the appellants. See In re Kemps,
97 F.3d 1427, 1430, 40 USPQ2d 1309, 1311 (Fed. Cir. 1996); In re
Beattie, 974 F.2d 1309, 1312, 24 USPQ2d 1040, 1042 (Fed. Cir.
1992); In re Dillon, 919 F.2d 688, 693, 16 USPQ2d 1897, 1901
(Fed. Cir. 1990) (en banc), cert. denied, 500 U.S. 904 (1991); In
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Application No. 10/209,004
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re Lintner, 458 F.2d 1013, 1016, 173 USPQ 560, 562 (CCPA 1972).
Sandhu and Hosaka would have fairly suggested, to one of ordinary
skill in the art, using Hosaka’s method in Sandhu’s method to
provide the above-discussed benefits disclosed by Hosaka.
The appellant argues that “Sandhu teach[es] away from the
use of polysilicon electrode materials such as those taught by
Hosaka because they are subject to oxidation” (brief, page 7).
This argument is not convincing because Hosaka teaches that the
electrode material can be platinum (page 5), which is the same
material used by Sandhu (col. 6, line 52).
The appellant argues that “while Hosaka teach[es] the use of
platinum as a possible electrode material, it is clear from
reading the reference that polysilicon is the preferred material
for use, as evidenced by Hosaka’s disclosure and working
examples” (brief, pages 7-8). We are not persuaded by this
argument because Hosaka is not limited to its preferred
embodiments, see In re Kohler, 475 F.2d 651, 653, 177 USPQ 399,
400 (CCPA 1973); In re Mills, 470 F.2d 649, 651, 176 USPQ 196,
198 (CCPA 1972); In re Bozek, 416 F.2d 1385, 1390, 163 USPQ 545,
549 (CCPA 1969), or to its working examples. See In re
Fracalossi, 681 F.2d 792, 794 n.1, 215 USPQ 569, 570 n.1 (CCPA
1982); Mills, 470 F.2d at 651, 176 USPQ at 198.
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Application No. 10/209,004
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The appellants argue that “there is no teaching or
suggestion in Hosaka as to how such metal electrode materials
should be etched if they are to be used in place of the
polysilicon film” (brief, page 8). Hosaka’s disclosure that the
electrode material can be platinum (page 5) indicates that one of
ordinary skill in the art would have been capable of forming an
electrode made of that metal. The appellant has provided no
evidence or technical reasoning to the contrary.
We therefore conclude that the method claimed in the
appellant’s claim 1 would have been obvious to one of ordinary
skill in the art over the applied prior art. Accordingly, we
affirm the rejection of that claim and claims 4-6 and 10 that
stand or fall therewith.
Claim 7
Claim 7 requires forming a layer of a barrier material in a
barrier hole such that the layer of barrier material contacts a
contact and is substantially coplanar with the surface of an
insulating layer. Such a structure is disclosed by Sandhu
(figure 10A, barrier hole containing barrier layer 75 (col. 5,
lines 64-65) substantially coplanar with insulating layer 40).
The appellant argues that Sandhu does not disclose forming
an electrode having a nodular shape (brief, page 9). This
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argument is not persuasive because, as discussed above regarding
the rejection of claim 2, Hosaka would have fairly suggested, to
one of ordinary skill in the art, forming Sandhu’s lower
electrode into a nodular shape.
The appellant argues that Hosaka does not form a contact
(reply brief, pages 3-4). Such a disclosure is not needed for
establishing a prima facie case of obviousness of the claimed
invention because Sandhu’s method includes forming a
contact (65).
For the above reasons we affirm the rejection of claim 7 and
claim 9 that stands or falls therewith.
Claim 8
Claim 8 requires planarizing a contact to make it
substantially coplanar with a surface of an insulating material.
Sandhu’s prior art figure 1 shows such a structure (contact 3
substantially coplanar with the insulating material on each side
of it).
The appellant questions why one of ordinary skill in the art
would have been motivated to use the prior art configuration
disclosed by Sandhu when Sandhu teaches away from it (brief,
page 8; reply brief, page 3). Sandhu teaches that he seeks to
provide increased density, decreased contact resistance between
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Application No. 10/209,004
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an electrode and a barrier layer, and reduced degradation of the
barrier layer compared to the prior art device (col. 2, lines 33-
38), but he does not disclose that the prior art device is not
functional. Hence, Sandhu and Hosaka would have fairly
suggested, to one of ordinary skill in the art, the use of
Hosaka’s method when making the prior art device disclosed by
Sandhu to improve the prior art device in the manner taught by
Hosaka, i.e., to remove surface roughness and distortions in the
lower electrode (1) and round the corner portions of the lower
electrode’s side surface to prevent degradation of the quality of
the thin insulating film formed on the lower electrode and to
obtain good electrical characteristics (page 3).
We therefore affirm the rejection of claim 8 and claim 11
that stands or falls therewith.
DECISION
Appeal No. 2005-1894
Application No. 10/209,004
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The rejection of claims 2 and 4-11 over Sandhu in view of
Hosaka is affirmed.
AFFIRMED
TERRY J. OWENS )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
JOSEPH F. RUGGIERO ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
JOSEPH L. DIXON )
Administrative Patent Judge )
Appeal No. 2005-1894
Application No. 10/209,004
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