Ex Parte Juengling

Patent Trial and Appeal Board

Jun 30, 2016

12950787 (P.T.A.B. Jun. 30, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR
12/950,787 11/19/2010 Werner Juengling
52142 7590 07/05/2016
FLETCHER YODER (MICRON TECHNOLOGY, INC)
P.O. BOX 692289
HOUSTON, TX 77269-2289
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
MICS:0326 (09-0493) 8443
EXAMINER
SLUTSKER, TIJLIA
ART UNIT PAPER NUMBER
2891
NOTIFICATION DATE DELIVERY MODE
07/05/2016 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):
docket@fyiplaw.com
manware@fyiplaw.com
s trickland @fyiplaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte WERNER JUENLING 1
Appeal2014-003210
Application 12/950,787
Technology Center 2800
Before ADRIENE LEPIANE HANLON, CATHERINE Q. TIMM, and
JAMES C. HOUSEL, Administrative Patent Judges.
HOUSEL, Administrative Patent Judge.
DECISION ON APPEAL
Pursuant to 35 U.S.C. § 134(a), Appellant appeals from the
Examiner's decision finally rejecting claims 1-8, 27-29, and 32-36. We
have jurisdiction over the appeal under 35 U.S.C. § 6(b ).
We REVERSE. 2
1 According to Appellant, the real party in interest is Micron Technology,
Inc. Appeal Br. 2.
2 Our decision refers to Appellant's Specification (Spec.) filed November 19,
2010, the Examiner's Final Office Action mailed April 4, 2013, Appellant's
Appeal Brief (Appeal Br.) filed October 4, 2013, the Examiner's Answer
(Ans.) mailed November 5, 2013, and Appellant's Reply Brief (Reply Br.)
filed January 6, 2014.
Appeal2014-003210
Application 12/950,787
STATEMENT OF THE CASE
The invention relates to double gate finFETs having a highly resistive
upper gate and a low resistive lower gate formed between each fin. Spec. i-f
11. Appellant discloses that the fin transistors may be operated by biasing
the gates such that the low gates provide preselection of a fin during biasing
of the upper gates. Id. As shown in Figure 9, reproduced below, Appellant
provides metal conductors 40 in the bottom of the trenches 24 forming lower
gates between pairs of fins 12, and conductors 52, 54 in the trenches above
the lower gates on opposing faces of the fins forming upper gates. 3
3 Throughout this Opinion, for clarity, we present labels to elements in
figures in bold font, regardless of their presentation in the original document.
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Application 12/950,787
Appellant's Figure 9 depicting a cross-sectional plane view of a portion of a
memory array of finFETs.
Appellant discloses that the lower and upper gates may be formed
over an oxide layer 36, and the conductor 40 may be formed over a
conductive liner 38. Spec. i-f 22. According to one embodiment, Appellant
discloses that the liner 38 may be separated into upper and lower portions,
where the lower portion underlies conductor 40 and the upper portions on
the sides of the fins form the upper gates. Spec. i-f 24. In another
embodiment, Appellant discloses that the upper gates may be separately
formed after formation of the lower gates. Spec. i-f 28.
Claim 1, reproduced below from the Claims Appendix to the Appeal
Brief, is illustrative of the subject matter on appeal (limitation at issue in
italics):
1. A semiconductor device, comprising;
a first fin and a second fin separated by a trench;
a first conductor disposed in the trench and extending
substantially parallel to a sidewall of the first fin and a
sidewall of the second fin to form a first gate, wherein the
first conductor substantially fills a bottom portion of the
trench; and
a second conductor disposed in the trench above the
first conductor and on the sidewall of the first fin to form a
second gate, wherein the second conductor is electrically
isolated from the first conductor; and
a third conductor disposed in the trench above the first
conductor and on the sidewall of the second fin to form a
third gate, wherein the third conductor is electrically isolated
from the first conductor.
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Application 12/950,787
Additional independent claim 27 similarly requires a lower gate formed in
the trench and "substantially fills a bottom portion of the first trench."
Remaining independent claim 32 recites a liner formed over an oxide layer
on the sidewalls and bottom surface of the trench, with a first conductor on
the liner forming a first gate, and a portion of the liner being separated to
form second and third gates on the sidewalls.
The Examiner maintains the following rejections:
A. The rejection of claims 1-3, 8, and 27-29 under 35 U.S.C.
§ 102(b) as anticipated by Bums;
B. The rejection of claims 4--6 and 32-36 under 35 U.S.C.
§ 103(a) as unpatentable over Bums in view ofDreeskomfeld; and
C. The rejection of claim 7 under 35 U.S.C. § 103(a) as
unpatentable over Bums.
With regard to rejection A above, Appellant separately argues
independent claims 1 and 27, as well as dependent claim 3. For reasons that
will become apparent later in this Opinion, we need not address Appellant's
arguments with regard to claim 3. In addition, Appellant's arguments with
regard to claims 1 and 27 are substantially similar. As such, we select claim
1 as representative.
With regard to rejection B above, Appellant's arguments focus on the
limitations of claim 32.
With regard to rejection C above, Appellant relies on the same
arguments with regard to claim 1. Therefore, our disposition as to rejection
A applies with equal force to rejection C.
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Application 12/950,787
ANALYSIS
Rejection A: Anticipation by Burns
The dispositive issue on appeal before us is whether Appellant has
identified reversible error in the Examiner's finding that Bums teaches a first
conductor forming a first gate in the trench, wherein the first conductor
"substantially fills a bottom portion of the trench." Claim 1.
We answer this question in the affirmative and, therefore, will not
sustain the Examiner's anticipation rejection by Bums.
The Examiner finds Bums' Figure 46, reproduced below, discloses a
semiconductor device comprising fins 230 separated by a trench, a first
conductor 725, 750 disposed in the trench and extending substantially
paraUei to the sidewaUs of the fins to form a first gate, wherein the first
conductor substantially fills a bottom portion of the trench. Final Act. 5.
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Application 12/950,787
IJitline 314
""' DirectionC 705
FIG. 46
Figure 46 of Bums, depicting a cross-sectional view of a memory array
The Examiner further finds Bums teaches second and third conductors 735
disposed in the trench above the first conductor on the sidewalls of the fins
to form second and third gates, respectively, wherein the second and third
conductors are electrically isolated from the first conductor. Id.
Appellant contends that Bums fails to teach a first conductor disposed
in the trench to form a first gate, wherein the first conductor substantially
fills a bottom portion of the trench. Appeal Br. 9. In particular, Appellant
asserts that Bums' device includes a first pair of wordlines (lower gates) 725
formed in the trench below a second pair of wordlines (upper gates) 735,
where each of the wordlines 725 take up less than half of the width of the
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Application 12/950,787
trench. Id. As such, Appellant argues that neither of wordlines 725
substantially fills a bottom portion of the trench. Id. Moreover, Appellant
asserts that the Examiner improperly reads element 750 as part of the first
conductor. Appeal Br. 10. Instead, Appellant argues that Bums teaches
element 750 is an n+ polysilicon material 585 that forms a deep trench
capacitor, not a gate. Appellant also argues that because element 750
appears to substantially fill a bottom portion of the trench, Bums does not
teach a first conductor forming a gate that substantially fills a bottom portion
of the trench. Id. Finally, Appellant argues that although the Examiner
appears to read elements 725, 750 as a single element, such an interpretation
of Bums is improper given that these elements are physically and electrically
separate elements having different functions. Appeal Br. 10-11.
In response, the Examiner finds Bums teaches a first conductor
contains two portions made of the same conducting materials, where a first
portion 750 substantiaUy fiUs a bottom portion of the trench, and a second
portion 725 forms a first gate. Ans. 4. The Examiner also finds that
Appellant's claims do not require the first conductor to be a single element
that is not physically separated. Id. Moreover, the Examiner finds the
phrase, "substantially fills a bottom portion," to be broad enough to include
a first conductor that fills a part of a bottom portion. Id. Finally, the
Examiner finds that claim 1 fails to define the boundaries of the trench,
thereby permitting "bottom portion" to include either the entire portion of
the trench in which capacitor 750 and wordlines 725 are formed, or the
portion 555 of the trench above capacitor 585 as shown in Figure 39. Ans.
4--5; see the Examiner's annotated Figures 39 and 46 of Bums. Where the
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Application 12/950,787
trench is the portion 555, the Examiner finds Bums' wordlines 725 would
substantially fill the bottom portion of the trench. Ans. 5.
We have considered the respective positions clearly articulated by the
Examiner and Appellant, and find a preponderance of the evidence supports
Appellant. As Appellant argues (Reply Br. 4 ), one of ordinary skill in the art
would interpret the trench 555 in Bums to extend the entire height of the
pillars 230, not just the partial height of pillars 230 above the n+ polysilicon
fill 585. See Bums, col. 22, 1. 8 ("n+ polysilicon 585 is deposited in the
trenches 555.") And as Appellant correctly notes (Reply Br. 4), deposition
of material into Bums' trenches does not reduce the depth of the trench.
Moreover, again as Appellant argues (id.), even if the trench were defined to
be the space above then+ polysilicon fill, wordlines 725 each appear to fill
less than half this space which would not reasonably read on "substantially
fill."
In this regard, we are mindfui of the fact that the Specification
provides little guidance as to the meaning of the term, "substantially" as an
adverb modifying the term "fills." Indeed, the Specification describes metal
conductor 40 formed in the row trenches and on the sidewalls of the fins,
and is subsequently removed to a depth 44, 61 by etching to form the bottom
or lower gates. Spec. i-f 22, 28. However, Appellant's Figures 9, 14, 16, and
1 7 each depict the metal conductor 40 filling the space in the bottom of the
trenches 24 not occupied by the oxide layer 36 and the liner 48. It is in this
context that one of ordinary skill in the art would understand the term,
"substantially," to be language of magnitude, i.e. not insubstantial or to a
significant extent. See, for example, Epcon Gas Systems, Inc. v. Bauer
Compressors, Inc., 279 F.3d 1022, 1031 (Fed. Cir. 2002) ("the phrase
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Application 12/950,787
'substantially below' signifies language of magnitude"); Deering Precision
Instruments, L.L.C v. Vector Distribution Systems, Inc., 347 F.3d 1314,
1323-1324 (Fed. Cir. 2003) ("the term 'substantially' in this context is used
as a term of magnitude.") Given this construction of claim 1, we cannot say
that Bums' wordlines 725 substantially fill either a bottom portion of the
space above then+ polysilicon material 585 or a bottom portion of the trench
in which capacitor 750 resides. In this regard, as Appellants contend, each
of Bums' wordlines 725 fill less than half of the bottom portion of the space
above then+ polysilicon material 585, and do not fill a bottom portion of the
trench in which capacitor 750 resides.
As to the Examiner's position that Bums' elements 725, 750 may be
read together as a first conductor, we agree with Appellant that such a
reading is unreasonable. Bums teaches element 725 is a wordline or gate
(Bums, col. 24, 11. 12-15), whereas element 7 50 is a deep trench capacitor
(id. at coi. 24, ii. 50-51 ), and elements 725, 750 are separated by oxide 600
(id. at Fig. 46). Where, as here, two structures are both physically separated
and perform different functions, reading these distinct structures as a single
structure is unreasonable.
"A claim is anticipated only if each and every element as set forth in
the claim is found, either expressly or inherently described, in a single prior
art reference." Verdegaal Bros., Inc. v. Union Oil Co. of Cal., 814 F.2d 628,
631 (Fed. Cir. 1987). In this case, the Examiner has not established that
Bums teaches each and every element as set forth in claim 1, in particular, a
first conductor that forms a first gate and substantially fills a bottom portion
of the trench. If follows that we will not sustain the Examiner's anticipation
rejection based on Bums.
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Appeal2014-003210
Application 12/950,787
Rejection B: Obviousness over Burns in view of Dreeskornfeld
For this rejection, Appellant directs their arguments to the rejection of
claim 32 only. Claim 32 is reproduced below.
32. A semiconductor device, comprising:
a first sidewall of a first fin, the first sidewall extending
in a first direction;
a second sidewall of a second fin, the second sidewall
extending in the first direction, wherein the first sidewall and
second sidewall generally define a trench having a bottom
surface;
an oxide on the first sidewall, second sidewall, and
bottom surface;
a liner on the first oxide;
a first conductor on the liner forming a first gate; and
wherein a portion of the liner is separated to form a
second gate on the first sidewall and a third gate on the second
sidewall.
The dispositive issue here is whether Appellant has identified
reversible error in the Examiner's finding that Bums teaches an oxide on the
bottom surface of the trench such that the Examiner's obviousness
conclusion is in error. Based on a proper construction of claim 32 with
regard to this limitation, we answer this question in the affirmative.
With regard to this claim, the Examiner finds that Bums discloses
opposing sidewalls of a pair of fins defining a trench having a bottom
surface, with an oxide 600 on the sidewalls and bottom surface, a first
conductor 730 forming a first gate, a second gate 720 (left) on a first
sidewall, and a third gate 720 (right) on a second sidewall. Final Act. 8.
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Application 12/950,787
The Examiner acknowledges that Bums does not disclose a liner on the first
oxide with the first conductor formed on the liner, nor that a portion of the
liner is separated. Id. The Examiner finds Dreeskomfeld discloses the
deposition of a liner before depositing a conductor for the purpose of
adjusting the threshold voltage of a transistor. Final Act. 9. The Examiner
concludes it would have been obvious to modify Bums by depositing a liner
on the first oxide and then depositing a first conductor on the liner for the
purpose of adjusting the threshold voltage of a transistor. Id. As for the
separation of the liner to form the second and third gates, the Examiner finds
this limitation to be a product-by-process limitation. Id. Since Bums
discloses second and third gates on the sidewalls of the fins, the Examiner
finds that this limitation is met. Id.
Appellant contends, inter alia, that Bums fails to teach an oxide layer
on the bottom surface of the trench because there is no oxide layer below the
n+ polysilicon material 585 or the p+ field isolation region 575. Appeal Br.
15. Appellant also argues that oxide 600 is not on a bottom surface of the
trench, which is not above then+ polysilicon material 585. Id.
In response, the Examiner finds that the phrase, "a bottom portion of
the trench," is broad in scope such that "any portion of the trench can be
considered as 'a bottom portion."' Ans. 8. In addition, the Examiner finds
that claim 32 fails to define the boundaries of the trench, thereby permitting
a trench of Figure 47 of Bums to read on the claimed trench. Id. As such,
the Examiner finds Bums' oxide 600 is on a bottom surface of a trench. Id.
We have considered the respective positions clearly articulated by the
Examiner and Appellant, and find a preponderance of the evidence supports
Appellant. In particular, we note that claim 32 does not recite "a bottom
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Application 12/950,787
portion of the trench" and, therefore, it is not reasonable to interpret
structure in Bums based on construing such language to meet limitations of
claim 32. Claim 32 recites a trench defined by the sidewalls of a pair of fins,
wherein an oxide is formed on the fin sidewalls and "a bottom surface" of
the trench. Thus, contrary to the Examiner's finding, claim 32 defines the
trench boundaries as the fin sidewalls and the bottom surface. As we
discussed above, Bums' trench does not change dimensions as it is filled
with material. Nor does the trench's bottom surface change as it is filled
with material. As such, oxide layer 600 is not on the bottom surface of
Bums' trench, but is on the deep trench capacitor 750. Accordingly, the
Examiner's finding that Bums teaches an oxide on the bottom surface of the
trench is not supported on the record before us. The Examiner does not rely
on Dreeskomfeld to remedy this deficiency in Bums. Under these
circumstances, we cannot conclude that the Examiner has met the minimum
threshold of estabiishing obviousness under 35 U.S.C. § 103(a). See In re
Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992); KSR Int 'l Co. v. Teleflex,
Inc., 550 U.S. 398, 418 (2007) (quoting In re Kahn, 441F.3d977, 988 (Fed.
Cir. 2006) ).
Rejection C: Obviousness over Burns
Claim 7 depends from claim 1, and further requires that the first
conductor comprises tungsten. The Examiner rejects dependent claim 7 as
obvious over Bums, but relies on the same erroneous finding discussed
above that Bums teaches the first conductor forms a first gate and
substantially fills a bottom portion of the trench. Accordingly, for the same
reasons given above, we will not sustain this rejection.
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Application 12/950,787
DECISION
Upon consideration of the record, and for the reasons given above and
in the Appeal Brief and Reply Brief, the decision of the Examiner rejecting
claims 1-8, 27-29, and 32-36 is reversed.
REVERSED
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