Ex Parte Okabe et al

Patent Trial and Appeal Board

Jan 19, 2018

12367581 (P.T.A.B. Jan. 19, 2018)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
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P.O.Box 1450
Alexandria, Virginia 22313-1450
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APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
12/367,581 02/09/2009 Takeo Okabe OGOSH30BUSA 1237
270 7590 01/23/2018
HOWS ON fr HOWS ON T T P
EXAMINER
350 Sentry Parkway HEVEY, JOHN A
Building 620, Suite 210
Blue Bell, PA 19422 ART UNIT PAPER NUMBER
1735
NOTIFICATION DATE DELIVERY MODE
01/23/2018 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
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PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte TAKEO OKABE and
HIROHITO MIYASHITA
Appeal 2017-003632
Application 12/367,581
Technology Center 1700
Before ADRIENE LEPIANE HANLON, MARK NAGUMO, and
WESLEY B. DERRICK, Administrative Patent Judges.
DECISION ON APPEAL
A. STATEMENT OF THE CASE
The Appellants filed an appeal under 35 U.S.C. § 134(a) from an Examiner’s
decision finally rejecting claims 1, 3, 5, 6, 21, 23, and 26.1 We have jurisdiction
under 35 U.S.C. § 6(b).
We AFFIRM.
Independent claims 1,5, and 6 are reproduced below from the Claims
Appendix of the Appeal Brief dated March 7, 2016 (“Br.”).
1. Semiconductor device wiring including a seed layer formed by
sputtering a target, said seed layer being of a copper alloy having a
1 Claims 8, 9, 14, and 15 are pending but have been withdrawn from consideration.
Appeal 2017-003632
Application 12/367,581
composition consisting of A1 in an amount of 0.5 to 4.0wt%, Si in an
amount of 0.5wtppm or less, and Cu as the remnant of the
composition.
Br. 24.
5. A seed layer for wiring of a semiconductor device, said seed
layer being formed by sputtering a target and made of a copper alloy
having a composition consisting of Sn in an amount of 0.5 to 4.0wt%,
Mn in an amount of 0.5wtppm or less, and Cu as the remnant of the
composition.
Br. 24.
6. A seed layer for wiring of a semiconductor, said seed layer
being formed by sputtering a target and made of a copper alloy having
a composition consisting of a combination of A1 and Sn in a total
amount of 0.5 to 4.0wt%, one of Si or Mn in an amount of 0.5 wtppm
or less, one or more elements selected from the group consisting of
Sb, Zr, Ti, Cr, Ag, Au, Cd, In and As in a total amount of 1.0 wtppm
or less, and Cu as the remnant of the composition.
Br. 25.
The claims on appeal stand rejected as follows:
(1) claims 1, 3, 5, 6, 21, 23, and 26 under 35 U.S.C. § 103(a) as
unpatentable over acknowledged prior art admission (APAA) in view of JP
2002038246 dated February 6, 2002 (JP 246);2
(2) claims 5, 6, 21, and 23 under 35 U.S.C. § 103(a) as unpatentable over
APAA in view of JP 1123040 dated May 16, 1989 (JP 040);3 and
(3) claims 5, 6, 21, 23, and 26 under 35 U.S.C. § 103(a) as unpatentable
over APAA in view of Yurasko.4
2 We refer to the English translation dated June 15, 2011.
3 We refer to the English translation dated October 5, 2016.
4 US 3,428,442, issued February 18, 1969.
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Application 12/367,581
B. DISCUSSION
We begin our discussion by interpreting the phrases “Si in an amount of
0.5wtppm or less” in claim 1 and “Mn in an amount of 0.5wtppm or less” in claim
5. Br. 24 (emphasis added). The Appellants do not expressly define the lower
limit of either claimed range (i.e., “or less”). Nonetheless, the Appellants disclose
several examples of the inventive copper alloys (i.e., Examples 1—5 (Spec. 14) and
Examples 6—10 (Spec. 15)). The Cu-Al alloy disclosed in Example 5 comprises
2.0 wt% A1 and no Si. Spec. 14. Similarly, the Cu-Sn alloy disclosed in Example
10 comprises 3.67wt% Sn and no Mn. Spec. 15. Thus, we interpret the range “Si
in an amount of 0.5wtppm or less” (Br. 24) to encompass no Si, whereby the
copper alloy recited in claim 1 consists of only Cu and Al. Likewise, we interpret
the range “Mn in an amount of 0.5wtppm or less” (Br. 24) to encompass no Mn,
whereby the copper alloy recited in claim 5 consists of only Cu and Sn. See Ans. 8
(concluding that claim 5 “merely requires 0.5 wt. % Sn, optional Mn, and Cu as the
remnant of the composition”).5
Consistent with our interpretation of claims 1 and 5, we interpret the phrase
“or less” in claim 6 encompass no Si, Mn, Sb, Zr, Ti, Cr, Ag, Au, Cd, In, and/or
As. See Ans. 6 (concluding that “[ajppealed claim 6 further contains Markush
group of nine additional optional elements”).
1. Claims E 5, and 6
The Examiner finds “APAA discloses that semiconductor wiring is known
to be sputtered with [a] Cu alloy seed layer on [a] barrier layer such as Ta/TaN.”
Ans. 3 (citing Spec. 3—4, 14). In particular, APAA discloses:
With the current formation process of copper wiring, often
times, after forming a diffusion barrier layer of Ta/TaN or the like in a
5 Examiner’s Answer dated September 22, 2016.
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Application 12/367,581
contact hole or the concave portion of a wiring groove, copper is
electroplated thereto. In order to perform this electroplating, as the
foundation layer (seed layer), generally, copper or copper alloy is
sputtered and deposited thereto.
Ordinarily, electrolytic copper having a purity of 4N (excluding
gas components) is employed as the crude metal in a wet or dry high
purification process to manufacture high purity copper having a purity
of 5N to 6N, and this was used as the sputtering target. Here, there
was no particular problem for copper wirings having a semiconductor
wiring width of up to 0.18pm.
Spec. 4—5 (emphasis added).
APAA also discloses that “a proposal has been made for adding Al or Sn . . .
to copper to obtain a copper alloy to be used as the target.... [T]his is for
improving the EM [electromigration] resistance, SM resistance or oxidation
resistance without hindering the low resistance characteristics of copper.” Spec.
114. The Examiner, however, does not find that APAA discloses a copper alloy
having a composition as claimed. Ans. 3, 4, 5 (finding that “APAA does not
disclose specific Cu alloy”).
The Examiner relies on JP 246 to show a copper alloy having a composition
within the scope of claims 1,5, and 6. The Examiner concludes that it would have
been obvious to one of ordinary skill in the art “to use high electrical conductive
Cu alloys for semiconductor seed layer in order to obtain all of the known benefits
such as high electrical conductivity . . . .” Ans. 3. The Examiner also relies on
JP 040 and Yurasko to show electrically conductive copper alloys within the scope
of claims 5 and 6 and makes a similar conclusion based on APAA in combination
with either JP 040 or Yurasko. Ans. 4, 5.
The Appellants acknowledge “that APAA generally discloses that it is
known in the field of semiconductor wiring that a seed layer of copper or a copper
alloy may be formed by sputter deposition on a barrier layer of, for example,
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Application 12/367,581
Ta/TaN.” Br. 6. Nonetheless, the Appellants contend that APAA does not provide
a solution to the problem of “coagulation” and “uneven electrodeposited texture,”
which is said to be solved by the claimed invention. Br. 6.
APAA describes the problem of “coagulation” and “uneven electrodeposited
texture” as follows:
[T]here were problems in that with ultra fine wiring where the
copper wiring width is 0.13pm or less', for instance 90 nm or 65 nm,
and the aspect ratio exceeds 8, the thickness of the seed layer would
become an ultra thin film of lOOnm or less, and, when forming a seed
layer with a 6Npurity copper target, coagulation would occur and a
favorable seed layer could not be formed.
[T]he uniformity of the foundation layer is important, and,
when the foundation layer becomes coagulated, it is not possible to
form a uniform film upon forming a copper film via electroplating.
For example, during wiring, defects such as voids, hillocks, and
disconnections are formed.
Spec. 6—7.
APAA does not disclose that the problem of “coagulation” occurs with the
copper wiring described in paragraph 5 of the Specification, which has a wiring
width of up to 0.18pm. Thus, we find the problem of coagulation is limited to the
ultra fine wiring described in paragraph 6 of the Specification, wherein the wiring
width is 0.13pm or less. Significantly, independent claims 1, 5, and 6 are not
limited to the ultra fine wiring described in paragraph 6. See Ans. 9 (concluding
that “there is no seed layer thickness in independent appealed claims 1,5, and 6
and no wiring width in any appealed claims”).
As for the copper alloys disclosed in JP 246, the Appellants do not direct us
to any credible evidence showing that JP 246 does not teach a copper alloy having
a composition as recited in claims 1,5, and 6. Rather, the Appellants argue that:
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Application 12/367,581
[JP 246] fails to disclose that its Cu-alloy may be subject to sputtering
for purposes of forming an ultra-thin film, such as a seed layer.
Instead, [JP 246] discloses a Cu alloy for a J-shaped electric terminal
that is disclosed as having a thickness of 0.25 mm (250,000 nm) (see
Paragraph No. 0039 of [JP 246]) and that is a material that needs to be
subject to plastic processing followed by low-temperature annealing
for purposes of providing the material with “spring characteristics”
(see Paragraph No. 0022 of [JP 246]).
Br. 9 (emphasis omitted).
The Appellants also argue that “[t]he effects of the Cu-based alloy taught in
[JP 246] (superior and long-lasting spring characteristics) are useless for a seed
layer.” Br. 13. Therefore, the Appellants argue that one of ordinary skill in the art
would not have expected the copper alloy disclosed in JP 246 to form a seed layer
via sputtering. Br. 13.
Similarly, the Appellants argue that JP 040 discloses a “bus bar as a bulk
material having a cold rolled structure” and Yurasko discloses “a composition of a
Cu-based alloy powder for use in spray welding” and neither JP 040 nor Yurasko
teaches the respective material is suitable for forming a seed layer via sputtering.
Br. 18, 20 (emphasis omitted).
The Appellants’ arguments are not persuasive of reversible error. In the
§ 103(a) rejections on appeal, the Examiner relies on JP 246, JP 040, and Yurasko
to show that copper alloys having the compositions recited in claims 1, 5, and 6
were known in the art at the time of the Appellants’ invention. The Examiner
proposes replacing the copper alloy in the sputtering target of APAA with other
high conductivity copper alloys, such as the copper alloys disclosed in JP 246, JP
040, and Yurasko. See Ans. 7; see Ans. 10 (finding that “regardless [of] the
history of the copper alloy/raw material, it would be melt [sic] to form a sputtering
target and sputtered”).
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On this record, the Appellants do not direct us to any credible evidence
showing that the copper alloys disclosed in JP 246, JP 040, and Yurasko would not
have been considered suitable for forming a seed layer on the copper wiring
described in paragraph 5 of the Appellants’ Specification. We recognize the
Appellants argue that JP 246, JP 040, and Yurasko do not disclose that the copper
alloys described therein are suitable for forming a seed layer. JP 246, JP 040, and
Yurasko, however, do not state that the disclosed copper alloys are not suitable for
forming a seed layer. Thus, the mere fact that JP 246, JP 040, and Yurasko do not
affirmatively state that the copper alloys are suitable for forming a seed layer does
not demonstrate their inability to form a seed layer on the copper wiring described
in paragraph 5 of the Appellants’ Specification.
For the reasons discussed above, the § 103(a) rejections of claims 1, 5, and 6
are sustained. The Appellants do not present arguments in support of the separate
patentability of claim 3. Therefore, the § 103(a) rejection of claim 3 is also
sustained.
Finally, we note that APAA discloses a copper alloy for forming a seed layer
that includes 0.5 wt% of Sn. In particular, paragraph 15 discloses:
Further, there is also a proposal stating that 0.5wt% of Sn is
effective in reducing the grain boundary diffusion and improving the
EM characteristics of Cu . . . . Nevertheless, this does not resolve the
coagulation problem (interaction) with the seed layer on the barrier
layer formed with the likes of Ta or TaN. [Emphasis added.]
The Examiner finds the composition disclosed in paragraph 15 is
substantially the same as the composition recited in claim 5. Ans. 8. The
Appellants do not direct us to any error in the Examiner’s finding. Rather, the
Appellants argue that APAA specifically teaches that the copper alloy described in
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Application 12/367,581
paragraph 15 cannot be used for forming a seed layer and cannot solve the
coagulation problem described in paragraphs 6 and 7 of the Specification. Br. 8.
As discussed above, on this record, the problem of “coagulation” is limited
to the ultra fine wiring described in paragraph 6 of the Specification, and claim 5 is
not limited to the ultra fine wiring described therein. Therefore, the § 103(a)
rejections of claim 5 based on APAA in view of any one of JP 246, JP 040, and
Yurasko are sustained for this additional reason. See In re Kalm, 378 F.2d 959,
962 (CCPA 1967) (a complete description in a reference is the epitome of
obviousness).
2. Claims 21, 23, and 26
Claim 23 depends from claim 5 and recites that “said seed layer has a
thickness of 50 to 500 nm.” Br. 26. Likewise, claim 21, which depends from
claim 6, and claim 26, which depends from claim 1, recite that “said seed layer has
a thickness of 50 to 500 nm.” Br. 26, 27.
The Examiner finds APAA discloses a conventional seed layer thickness.
See Ans. 3 (citing Spec. ]Hf 5—6). In particular, paragraph 6 of the Appellants’
Specification discloses that a seed layer having a thickness of lOOnm or less, which
overlaps the claimed range, was known in the art at the time of the Appellants’
invention.
The Appellants do not dispute that lOOnm or less was known to be a
conventional seed layer thickness. Rather, the Appellants argue that paragraph 6
of their Specification states that “with a copper target having a purity level of 6N,
it is not possible to form a favorable seed layer having a thickness of 100 nm or
less” and “APAA makes no reference to the thickness of a copper alloy seed layer”
having the claimed compositions. Br. 16 (emphasis omitted). The Appellants also
argue that JP 246 does not teach the claimed thickness. Br. 17. The Appellants
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Application 12/367,581
make similar arguments as to APAA in combination with either JP 040 or
Yurasko. Br. 19, 22.
We recognize the Appellants disclose that coagulation would occur at a
thickness of lOOnm or less. See Spec. 1 6. However, that disclosure is limited to
ultra fine wiring where the copper wiring width is 0.13 pm or less, the aspect ratio
exceeds 8, and the seed layer is formed with a 6N purity copper target. In contrast,
the Examiner finds:
At aspect ratio 4 and seed layer thickness at 50 nm, the wiring width
calculated is 200 nm or 0.2 pm and seed layer thickness at 500 nm,
the wiring width calculated is 2000 nm or 2 pm. According to APAA
instant specification paragraph [0005] that “. . . there was no
particular problem for copper wirings having a semiconductor wiring
width of up to 0.18 gm”
Ans. 9 (emphasis added).
The Appellants do not direct us to any error in the Examiner’s findings.
Therefore, the rejection is sustained.
C. DECISION
The Examiner’s decision is affirmed.
No time period for taking any subsequent action in connection with this
appeal may be extended under 37 C.F.R. § 1.136(a)(1).
AFFIRMED
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