Ex Parte Xu et al

Patent Trial and Appeal Board

Feb 27, 2018

14373628 (P.T.A.B. Feb. 27, 2018)

UNITED STATES PATENT AND TRADEMARK OFFICE
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.
14/373,628 07/21/2014 Qiuxia Xu 5006.0006WU1 7653
112610 7590 02/27/2018
Christensen, Fonder, Dardi & Herbert PLLC
33 South Sixth Street
Suite 3950
Minneapolis, MN 55402
EXAMINER
GARBER, CHARLES D
ART UNIT PAPER NUMBER
2812
MAIL DATE DELIVERY MODE
02/27/2018 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
_________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte QIUXIA XU, GAOBO XU,
HUAJIE ZHOU, HUILONG ZHU, and
DAPENG CHEN
__________

Appeal 2017-002487
Application 14/373,6281
Technology Center 2800
___________

Before ROMULO H. DELMENDO, KAREN M. HASTINGS, and
JAMES C. HOUSEL, Administrative Patent Judges.

PER CURIAM.

DECISION ON REHEARING

Appellant requests rehearing of a Decision on Appeal mailed
September 27, 20172 affirming the Examiner’s decision that claims 1–14 and
18–20 are unpatentable over the applied prior art.
A Request for Rehearing3 must state with particularity the points

1 Appellant is the Applicant, Institute of Microelectronics, Chinese Academy
of Sciences, which, according to the Appeal Brief, is the real party in interest
Appeal Brief (Appeal Br.) filed April 29, 2016. Appeal Br. 3.
2 Hereinafter, “Decision.”
3 Hereinafter, “Request”.
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believed to have been misapprehended or overlooked by the Board.
Arguments not raised and evidence not previously relied upon in the Briefs
before the Board are not permitted in a Request for Rehearing except as
permitted by 37 C.F.R. §§ 41.52(a)(2) and (a)(3). See 37 C.F.R.
§ 41.52(a)(1) (2016).
We have reconsidered the Decision in light of Appellant’s comments
in the Request and find no error in the disposition of the affirmed rejections.
We remain of the opinion that the subject matter of the claims is
unpatentable in view of the applied prior art.
I.
The Board’s Decision affirmed the Examiner’s rejection under
35 U.S.C. § 103(a) of claims 1, 6–8, 10, 18, and 20 over Xu ’3284 in view of
Gulari5 and Ramin.6
In the Request, Appellant requests reconsideration of the rejection for
claim 1. Request 2–8. Appellant argues that it is not their burden to identify
an error because the Examiner has merely made allegations without meeting
the Examiner’s burden of establishing a prima facie case of obviousness.
Request 5. We disagree. “[T]he examiner bears the initial burden, on
review of the prior art or on any other ground, of presenting a prima facie

4 Xu et al., CN 102339858 A, published Feb. 1, 2012. The Examiner cites
Xu et al. by its application number, 201010233549 (Final Office Action
(Final Act.) mailed Sept. 29, 2015, Final Act. 2), instead of the publication
number. Further references to Xu et al. will refer to US 2013/0099328 A1,
published Apr. 25, 2013 (“Xu ’328”), which the Examiner indicates is an
English language equivalent. Id.
5 Gulari et al., US 2006/0163671 A1, published July 27, 2006 (“Gulari”).
6 Ramin et al., US 2008/0237743 A1, published Oct. 2, 2008 (“Ramin”).
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case of unpatentability. If that burden is met, the burden of coming forward
with evidence or argument shifts to the applicant.” In re Oetiker, 977 F.2d
1443, 1445 (Fed. Cir. 1992). Here, the Examiner has set forth a prima facie
case of obviousness based upon the teachings of the prior art regarding
dopants to adjust the work function of a gate electrode of a transistor. As a
result, the burden has shifted to the Appellant to identify a reversible error in
the Examiner’s rejection. In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011)
(rejecting the argument that the Board improperly shifted the burden to
identify a reversible error where the examiner established a prima facie case
of unpatentability and the burden was properly shifted to the applicant to
rebut it).
Appellant further disputes that the applied references, particularly Xu
’328 and Ramin, recognize aluminum and boron as equivalents for p-type
doping of a metal gate layer because Ramin discloses a Group IIIa element
as a dopant for polysilicon of a PMOS (p-type metal oxide semiconductor),
not a dopant to alter the work function of a metal gate layer. Reply Br. 3–5.
Appellant further argues that simply because two elements are equivalent in
one aspect, such as for doping polysilicon gates, does not mean that the two
elements are equivalent in other aspects, such as being dopants to adjust the
work function of a metal gate electrode, as recited in claim 1. Id. at 5.
Appellant’s arguments are unpersuasive. As stated at pages 4–5 of the
Decision, the Examiner finds Xu ’328 discloses the introduction of
aluminum into a gate stack but does not disclose implanting dopant ions in a
metal gate layer to increase an effective work function of a PMOSFET,
wherein the dopant is selected from In, B, BF2, Ru, W, and Mo. See Final
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Act. 3. The Examiner finds Ramin teaches that aluminum and boron are
equivalent p-type dopants for gate electrodes. Decision 5; Final Act. 4.
Xu ’328 discloses a semiconductor device that includes a substrate
1000,7 isolation structures 1022, an oxide layer (not depicted in the drawings
of Xu ’328), a second dielectric layers 1004 and 1008 that each contain
aluminum, a first dielectric layer 1006 that is a high-K gate dielectric layer, a
first metal layer 1010 (i.e., metal gate layer) comprising a metal nitride
including aluminum, a second metal layer 1012, a polysilicon layer 1014,
forming a gate stack from the layers, and a sidewall spacer 1016. Xu ’328
¶¶ 25, 28, 32, 33, 38, 51. Xu ’328 further discloses annealing a
semiconductor device after formation of source/drain regions to form Al–O
dipoles. Xu ’328 ¶ 53. Specifically, the aluminum provided in the gate
dielectric layers 1004 and 1008 and in the gate electrode 1010 form Al–O
electric dipoles at the interface for the high-K gate dielectric layer and the
metal gate layer. Id. ¶¶ 46, 37, 56. Xu ’328 teaches that the dipoles change
the energy level at the interface, which affects the gate work function. Id.
¶¶ 37, 56. In addition, Xu ’328 discloses its invention is useful for tuning
the work function of a PMOS metal gate. Id. ¶ 20.
Ramin discloses a PMOS transistor in which a dopant is used to adjust
the work function of the transistor and convert a polysilicon electrode to a
fully silicided gate electrode. Ramin ¶ 9. Ramin discloses a work function
adjustment by implanting a p-type dopant into an exposed gate electrode
made of polysilicon. Id. ¶¶ 9, 45. Specifically, Ramin discloses:
The PMOS work function adjustment implant 230 is now
performed on the exposed region containing the PMOS transistor

7 Throughout this Decision, for clarity, we present labels to elements in
figures in bold font, regardless of their presentation in the original document.
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60. Specifically, p-type dopants selected from the Group Illa
series (e.g. B, Al, Ga, In, Tl) are implanted into the exposed gate
electrode 113 of the PMOS transistor 60.
Id. ¶ 45. Thus, Ramin does not merely disclose that boron and aluminum
are equivalent p-type dopants, but are equivalents for adjusting the work
function of a gate electrode for a transistor. We are not saying that boron
and aluminum are identical in their level of performance as dopants to adjust
the work function of a gate electrode but that the applied references
demonstrate they are equivalent for adjusting the work function of a gate
electrode.
Appellant asserts that the mere fact that components are members of a
Markush group does not establish equivalency of the components. Request
4. This argument does not address the rejection because Ramin teaches that
aluminum and boron are examples of p-type dopants that can be used to
adjust the work function of a gate electrode. Thus, either aluminum or boron
could be used for this purpose in view of Ramin’s disclosure.
With regard to Appellant’s arguments that Xu ’328 discloses a gate
electrode made of a metal nitride but Ramin discloses a gate electrode made
of polysilicon, Ramin discloses that boron or aluminum can be used to adjust
the work function of an electrode for a transistor. Ramin ¶¶ 9, 45.
Appellant does not direct us to any evidence or persuasive technical
reasoning that boron would not function to adjust the work function of the
particular metal gate layer materials of Xu ’328. Appellant asserts that
observations such as these improperly shifts the burden. Request 6. This is
unpersuasive. As noted above, the Examiner’s prima facie case of
obviousness has shifted the burden to Appellant to identify a reversible
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error, not determinations by the Board regarding the merits of Appellant’s
arguments, reasoning, and evidence.
Moreover, we note Schulz8 discloses implanting a dopant species to
tune the work function of a metal gate electrode. Schulz ¶ 67. Schulz
discloses that the dopant species can be boron and that the metal gate
electrode material can be TiAlN (Schulz ¶ 69), which is one of the materials
disclosed by Xu ’328 for its metal gate electrode (Xu ’328 ¶ 46). Therefore,
the disclosure of Schulz serves as additional evidence that boron would
function to adjust the work function of a metal gate electrode, including a
particular metal gate electrode of Xu ’328.
Appellant contends “Schulz does not demonstrate that testing or
manufacturing a metal gate doped with B or BF2 ions had actually been
achieved” and that “the lack of known testing or actual manufacture of a
metal gate doped with B, BF2 is a factor in generally demonstrating non-
obviousness.” Request 7–8. These arguments are unpersuasive. A
reference is presumed to be enabling. In re Sasse, 629 F.2d 675, 681 (CCPA
1980) (it is applicant’s burden to demonstrate non-enablement of a
reference). Appellant merely asserts that Schulz lacks actual testing without
providing any evidence or persuasive technical reasoning that the disclosure
of Schulz would not enable one of ordinary skill in the art to dope a metal
gate electrode of a transistor, such as a gate electrode made of TiAlN, with
boron to tune its work function without undue experimentation. Therefore,
Appellant has not met their burden of showing that the disclosure of Schulz

8 Schulz et al., US 2007/0075351 A1, published Apr. 5, 2007 (“Schulz”).
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does not enable one of ordinary skill in the art to make the transistor it
discloses.
Appellant also argues that Schulz contemplates thousands of
combinations of different gate materials and dopant species. Request 8. As
discussed above, Schulz expressly teaches boron as a dopant species to tune
the work function of a gate electrode and expressly discloses that the gate
electrode material can be TiAlN. Moreover, the disclosure of many
effective combinations does not negate the obviousness of any of those
combinations. See, e.g., Merck & Co. v. Biocraft Labs., Inc., 874 F.2d 804,
807 (Fed. Cir. 1989) (“That the [prior art] patent discloses a multitude of
effective combinations does not render any particular formulation less
obvious. This is especially true because the claimed composition is used for
the identical purpose taught by the prior art.”).
The 37 C.F.R. § 1.132 Declaration of Qiuxia Xu (“Declaration”)
submitted February 29, 2016 includes statements regarding whether
aluminum and boron are equivalents for doping metal gates. Specifically,
the Declaration states aluminum ions are not compatible with CMOS Front
End of Line (FEOL) processes because the aluminum ions will cause
contamination; aluminum tends to form alumina, which causes degradation
of performance; and the ability of aluminum to adjust an effective work
function is less than that for boron or BF2. Declaration ¶¶ 4–6. However, to
the extent these statements may demonstrate differences between aluminum
and boron as dopants or differences in their effectiveness as dopants, the
statements fail to demonstrate that both aluminum and boron are not useful
as dopants to adjust the work function of a transistor, as suggested by the
disclosures of Xu ’328 and Ramin. In fact, these statements appear to be
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rebutted by the disclosure of Schulz, which provides evidence that it was
known to use boron to dope a metal gate electrode and tune its work
function, as discussed above.
The Declaration also includes statements addressing whether it would
have been obvious to select B or BF2 over Al as a dopant. Id. ¶¶ 7–9. These
statements are entitled to little weight because they regard legal issues
without considering and discussing the prior art disclosures in a meaningful
way. In re Reuter, 670 F.2d 1015, 1023 (CCPA 1981) (expert’s opinion on
ultimate legal issue entitled to no weight); cf. Icon Health and Fitness, Inc.
v. Strava, Inc., 849 F.3d 1034, 1041 (Fed. Cir. 2017) (“[W]e frequently have
affirmed PTAB determinations on obviousness that rely on expert
declarations that include such statements, so long as other aspects of the
declarations contain statements related to factual findings.”). In addition,
these statements regard the personal knowledge of the declarant and lack
factual support and are, therefore, conclusory.
In view of the above, the Declaration is entitled to little weight.
Having weighed all of the evidence before us, including the Declaration and
the disclosures of the applied references, we are convinced that a
preponderance of the evidence supports the conclusion that the claimed
invention would have been obvious to one of ordinary skill in the art.
Appellant further contends there is no basis for boron having an effect
upon the work function of a gate electrode as an inherent property or
characteristic that necessarily flows from the disclosures of Xu ’328 and
Ramin. Request 6–7. Inherency is unnecessary here because the applied
references, such as Ramin, disclose that boron functions as a dopant to
adjust the work function of a transistor, as discussed above.
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Appellant does not argue claims 6–8, 10, 18, and 20 separately from
claim 1. Request 3–8.
Accordingly, Appellant has not persuasively shown that the Board
misapprehended or overlooked any of the arguments raised in the Briefs or
that the Decision to affirm the rejection of claims 1, 6–8, 10, 18, and 20
should otherwise be modified or reversed.

II.
The Board’s Decision also affirmed the following rejections under
35 U.S.C. § 103(a):
 claims 2–5 and 12–14 over Xu ’328, Ramin, and Gulari and
further in view of Xu ’447;9
 claim 9 over Xu ’328, Ramin, and Gulari and further in view of
Im;10
 claim 11 over Xu ’328, Ramin, and Gulari and further in view
of Schulz; and
 claim 19 over Xu ’328, Ramin, and Gulari and further in view
of Mollard.11
Appellant does not argue these claims separately from claim 1.

9 Xu et al., CN 102280376 A, published Dec. 14, 2011. The Examiner cites
Xu et al. by its application number, 201010199981 (Final Act. 5), instead of
the publication number. Further references to Xu et al. will refer to US
2012/0094447 A1, published Apr. 19, 2012 (“Xu ’447”), which the
Examiner indicates is an English language equivalent. Id.
10 Im et al., US 8,354,671 B1, issued Jan. 15, 2013 (“Im”).
11 Mollard et al., US 2014/0319580 A1, published Oct. 30, 2014
(“Mollard”).
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Request 8–9. As discussed above, Appellant has not persuasively shown
that the Board misapprehended or overlooked any of the arguments raised in
the Briefs or that the Decision to affirm the rejection of claim 1 should
otherwise be modified or reversed. Therefore, Appellant has not
persuasively shown that the Decision to affirm the rejections of claims 2–5,
9, 11–14, and 19 should otherwise be modified or reversed.

III.
Appellant’s Request for Rehearing has been granted to the extent that
the Decision has been reconsidered in light of Appellant’s arguments.
However, the Request is otherwise denied, and the Decision is not modified
in any respect.
This Decision on the Request for Rehearing incorporates our
Decision, mailed September 27, 2017, and is final for the purposes of
judicial review. See 37 C.F.R. § 41.52(a)(1).

IV.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

REHEARING DENIED