Ex Parte Yau et al

Patent Trial and Appeal Board

Nov 20, 2013

11877488 (P.T.A.B. Nov. 20, 2013)

UNITED STATES PATENT AND TRADEMARKOFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
11/877,488 10/23/2007 Wai-Fan Yau 002592 USA C 13
DSM/LOW K
7994
44257 7590 11/21/2013
PATTERSON & SHERIDAN, LLP - - APPM/TX
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON, TX 77056
EXAMINER
PIZARRO CRESPO, MARCOS D
ART UNIT PAPER NUMBER
2814
MAIL DATE DELIVERY MODE
11/21/2013 PAPER
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.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
PATENT TRIAL AND APPEAL BOARD
____________

Ex parte APPLIED MATERIALS, INC.
(Application 11/877,488)
____________

Appeal 2011-009396
from Technology Center 2800
Marcos D. Pizarro, Primary Examiner
____________

Before RICHARD TORCZON, DEBORAH KATZ and HUNG H. BUI,
Administrative Patent Judges.

TORCZON, Administrative Patent Judge.

DECISION ON APPEAL
The appellant (AMI) seeks relief from the final rejection of claims 1-3. We
AFFIRM.

Appeal 2011-009396 Application 11/877,488

2
OPINION
AMI's specification discloses "a process and apparatus for depositing
dielectric layers on a semiconductor substrate."1 Claim 1, the sole independent
claim on appeal, defines the invention as:2
An integrated circuit structure, comprising:
regions of dielectric material separating regions of conductive
material within a layer, wherein the regions of dielectric material
comprise:
a first dielectric material comprising a porous low k dielectric
material; and
a second dielectric material comprising silicon, oxygen, and
carbon, wherein the second dielectric material has a carbon content
from 1 % to 50% by atomic weight and forms a low k lining layer
between the first dielectric material and the regions of conductive
material.
"Low k" means the dielectric constant is less than 4.0.3 The claim uses
"comprising" or "comprise" at several points, which opens the claim up to the
inclusion of additional, unlisted elements otherwise consistent with the claimed
subject matter.4 Thus, while the claim requires a first and a second dielectric
material in each dielectric region, there could be more than two, as long as the
second dielectric material forms a layer between the first dielectric material and
conductive material.
On appeal, the examiner maintains a rejection of claims 1-3 as having been
obvious5 from the combined disclosures of patents to Cheung6 and Bacchetta.7

1 Spec., ¶0002.
2 All claim language comes from the claims appendix. Br. 16; Ans. 4 (item (7)).
3 Spec. ¶0005.
4 Genentech, Inc. v. Chiron Corp., 112 F.3d 495, 501 (Fed. Cir. 1997).
5 Ans. 4 (item 9), citing 35 U.S.C. 103.
6 R.W. Cheung, Layered low dielectric constant technology, U.S. Pat. 5,534,731
(1996).
Appeal 2011-009396 Application 11/877,488

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FACTS AND FINDINGS
Cheung
[1] Cheung discloses a layered dielectric structure separating a first layer of metal
interconnects from each other and also from a second, overlying layer of metal
interconnects.8
[2] Cheung Figure 1 (right) shows a
cross-sectional view of the layered
dielectric structure, illustrating the
device up through the second
interconnect layer.9
[3] A silicon substrate 10 supports a first
layer of metal interconnects 12
separated by dielectric regions 14.10
[4] The dielectric region 14 has a plasma-enhanced chemical vapor deposited
(PECVD) silicon oxide layer 16, an organic spin-on glass (SOG) layer 18, a second
PECVD silicon oxide layer 20 and an inorganic SOG layer 22, followed by a third
PECVD silicon oxide layer 24 and a second inorganic SOG layer 26.11
[5] Cheung identifies commercially available inorganic SOGs with a dielectric
constant of about 3.2.12

7 M. Bacchetta, L. Zanotti & G. Queirolo, Process for the production of a
semiconductor device having better interface adhesion between dielectric layers,
U.S. Pat. 6,153,537 (2000, filed 1995).
8 Cheung, abstract.
9 Id. at 2:35-37.
10 Id. at 4:8-10.
11 Id. at 4:20-29.
12 Id. at 3:55-56.
Appeal 2011-009396 Application 11/877,488

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[6] Cheung explains that newer SOGs with higher carbon content have even lower
dielectric constants, but require extra care lest the carbon be oxidized in subsequent
processing steps.13
Cheung has identified a potential problem in using high-carbon dielectric
materials, but we do not consider a caution that care would be required to amount
to a teaching away even for high-carbon materials.
[7] Cheung teaches sealing off the inorganic SOG layer with a thin PECVD oxide
layer, providing dielectric layers with a lower dielectric constant that a single
dielectric material would provide.14
[8] The examiner finds that the inorganic SOG layer 22 comprises a porous low-k
dielectric material and the second PECVD silicon oxide layer 20 comprises a low-
k dielectric material with silicon and oxygen.15
[9] The examiner finds that Cheung fails to teach a second dielectric material with a 1-
50% carbon content.16
[10] Cheung explains that those skilled in the art could adapt the invention various
fabrication technologies and would know which fabrication steps could be changed
while attaining similar results.17
Bacchetta
[11] Bacchetta discloses a method for improving adhesion at the interface between
layers of dielectric material in a semiconductor device, particularly using a ternary
dielectric compound of silicon, oxygen and carbon.18

13 Id. at 2:58-3:7.
14 Id. at 3:66-4:6.
15 Ans. 4-5.
16 Id. at 5.
17 Cheung at 5:2-7.
18 Bacchetta at 1:8-16.
Appeal 2011-009396 Application 11/877,488

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[12] Bacchetta explains that those in the art knew that adhesion is a function of the
composition and structure of the layers.19
[13] Bacchetta reports "that the presence of carbon in the adhesion layer achieves
effective adhesion between a first dielectric material layer and a second dielectric
material layer superimposed in a semiconductor device, regardless of the chemical
composition and the surface condition of the layers."20
[14] Bacchetta Figure 1 (right) shows a cross-
section of a semiconductor device
including an adhesion layer.21
[15] A substrate 1 has a first conductive
layer 2, a first dielectric layer 3, a
planarization material (such as SOG) 4, a
second dielectric 5, an adhesive layer 6
and a second conductive layer 7.22
[16] Bacchetta addresses the oxidation
problem by advising that the adhesive layer be "formed at low
temperature and in an atmosphere kept essentially free from exogenous oxidative
substances before formation of the second dielectric layer."23
[17] Bacchetta explains that "exogenous oxidative substances" in this context means
oxygen from sources other than the sources of the carbon and silicon.24
[18] The dielectric layers may be formed by various techniques known in the art,
including PECVD.25

19 Id. at 2:45-51.
20 Id. at 3:37-43.
21 Id. at 3:61-64.
22 Id. at 7:28-43.
23 Id. at 3:44-47.
24 Id. at 3:47-50.
Appeal 2011-009396 Application 11/877,488

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[19] Bacchetta provides a preferred embodiment with atomic concentrations
(1021 atoms/cm3) of 15 to 27 for the silicon, 28 to 50 for the oxygen, 2.5 to 4.5 for
the carbon and (optionally) 0.8-1.3 of hydrogen.26
[20] The examiner finds that Bacchetta teaches a carbon content in the adhesive layer of
1-50% by atomic weight.27
AMI disputes whether Bacchetta teaches or suggests "a second dielectric
material comprising silicon, oxygen, and carbon, wherein the second dielectric
material has a carbon content from 1 % to 50% by atomic weight and forms a low
k lining layer between the first dielectric material and the regions of conductive
material".28 It is not clear which finding is being disputed. We find no basis for
doubting that Bacchetta teaches a carbon content of 1-50% by atomic weight in the
adhesive dielectric layer.
[21] As AMI notes, Bacchetta does not teach that the adhesive dielectric layer has a low
dielectric constant.29
AMI notes,30 and we agree, that the art does not suggest that the addition of
carbon in itself lower the dielectric constant for a dielectric layer.
[22] Bacchetta states that those skilled in the art would know how to change the
materials, shapes and dimensions as need requires while still achieving the
advantage of the improvement.31

25 Id. at 4:34-40 & 49-52.
26 Id. at 6:27-32.
27 Final Rej. 3.
28 Br. 10.
29 Br. 12; Bacchetta, passim.
30 Reply 2.
31 Bacchetta 9:1-11.
Appeal 2011-009396 Application 11/877,488

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ANALYSIS
A person having ordinary skill in the art is presumed to be able to combine
teachings and suggestions for their disclosed advantages, even if the combination
would require some modification.32 A teaching away, an unlikelihood that the
combination would work or some comparable evidence against the combination is
required to overcome this presumption.33
AMI urges that Cheung teaches away from the use of carbon because of the
risk during subsequent oxidation steps of carelessly damaging the circuit.34 The
threshold for a genuine teaching away is fairly high—mere cautions are not
sufficient—rather we must weigh the pros and cons as we would expect a person
having ordinary skill in the art to weigh them.35 In this case, Cheung's caution
about high-carbon materials does not even exclude their use inasmuch as Cheung
also recommends a solution within the skill in the art: the exercise of care.
Bacchetta provides additional solutions such as controlling the temperature and the
amount of exogenous carbon. In any case, neither Cheung nor Bacchetta requires
the use of high-carbon materials. Moreover, implicit in the multi-layered approach
of both references, a capping layer would shield a carbon-containing layer in a
subsequent oxidation step. In sum, we cannot find support for a genuine teaching
away from the use of carbon in this record.

32 In re Etter, 756 F.2d 852, 859 (Fed. Cir. 1985) (en banc); Transocean Offshore
Deepwater Drilling, Inc. v. Maersk Contractors USA, Inc., 617 F.3d 1296, 1304
(Fed. Cir. 2010).
33 KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 416, 420 (2007); In re Sovish,
769 F.2d 738, 742 (Fed. Cir. 1985).
34 Br. 10-11.
35 In re Young, 927 F.2d 588, 591 (Fed. Cir. 1991).
Appeal 2011-009396 Application 11/877,488

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AMI urges that Bacchetta does not teach a low-k adhesion layer.36
Moreover, Bacchetta teaches uses of the adhesive dielectric layer between other
dielectric layers rather than between the first dielectric layer and a conductive
layer.37 AMI misapprehends the examiner's rejection, which posits that a person
having ordinary skill in the art would add carbon to Cheung's low-k lining
dielectric (e.g., 20), which is between another low-k dielectric 22 and a conductive
material 12 to achieve the added advantage of better adhesion between layers. In
Cheung's illustrated embodiment, the second dielectric layer 20 is between a first
dielectric layer 22 and two other dielectric layers 16, 18. This proposed
combination would preserve the advantages of Cheung's multiple, low-k dielectric
layers, while improving adhesion between at least some of those layers as
Bacchetta teaches. AMI provides no evidence that adding the small amount of
carbon that Bacchetta contemplates adding to the adhesive dielectric layer would
significantly change the dielectric constant of the dielectric layer. Bacchetta's
silence in the face of a significant change in the dielectric constant would be
surprising since Bacchetta expects the adhered dielectric layers to continue to
function as a dielectric region.
AMI urges that adding carbon to Cheung's capping layer 20 would render it
inoperable to protect the underlying SOG layer 18 from oxidation damage. As an
initial matter, AMI provides only attorney argument for the proposition that the
proposed modification would render the invention inoperable.38 Moreover, as
discussed above in the context of teaching away, the art does not consider the
oxidation problem to be insuperable.

36 Br. 12.
37 Id.
38 In re Geisler, 116 F.3d 1465, 1470 (Fed. Cir. 1997) (explaining that attorney
argument is no substitute for evidence).
Appeal 2011-009396 Application 11/877,488

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AMI has offered no separate argument for claims 2 and 3 so they stand or
fall with claim 1.39
HOLDING
Final rejection of claims 1-3 is—
AFFIRMED

For the appellant: KEITH M. TACKETT, Patterson & Sheridan, LLP, of Houston,
Texas.

kmm

39 37 C.F.R. § 41.37(c)(1)(vii); C.W. Zumbiel Co., Inc. v. Kappos, 702 F.3d 1371,
1378 n.2 & 1381 n.4 (Fed. Cir. 2012).