Ex Parte Ding et al

Patent Trial and Appeal Board

Apr 18, 2013

11529166 (P.T.A.B. Apr. 18, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte MENG DING, AMOL JOSHI, TAKASHI ORIMOTO,
JAYENDRA BHAKTA, LEI XUE, SATOSHI TORII, and ROBERT
BERTRAM OGLE, JR.1
____________

Appeal 2011-006174
Application 11/529,166
Technology Center 2800
____________

Before KARL D. EASTHOM, JAMES B. ARPIN, and GEORGIANNA W.
BRADEN, Administrative Patent Judges.

ARPIN, Administrative Patent Judge.

DECISION ON APPEAL
STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
rejection of claims 1-7 and 15-20. We have jurisdiction under 35 U.S.C. §
6(b). Claims 8-14 are cancelled. Br. 2. 2 We affirm.

1 GLOBALFOUNDERIES Inc. and Spansion LLC are the real parties-in-
interest.
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INVENTION
Appellants’ invention relates to structures, for example, flash memory
cells, and electronic systems, which may include a transistor gate dielectric
stack situated on a semiconductor substrate. See generally Abstract. The
transistor gate dielectric stack may include a bottom oxide layer, a silicon-
rich nitride layer situated on the bottom oxide layer, a low silicon-rich
nitride layer situated on the silicon-rich nitride layer, and a top oxide layer
situated on the low silicon-rich nitride layer. Id. In another embodiment,
the flash memory cell may include a high-K dielectric layer situated on the
transistor gate dielectric stack. Id. Claim 1 is illustrative and is reproduced
below with disputed limitations emphasized:
1. A structure comprising:
a bottom oxide layer in a transistor gate dielectric stack situated
over a semiconductor substrate;
a silicon-rich nitride layer situated over said bottom oxide
layer;
a separate low silicon-rich nitride layer situated over said
silicon-rich nitride layer, wherein said separate low silicon-rich
nitride layer contains a lower silicon concentration than said silicon-
rich nitride layer.

The Examiner relies on the following as evidence of unpatentability:
Jenne
Han
Chen
Jung
Lee

Takiar
US 6,709,928 B1
US 6,849,514 B2
US 2005/0199944 A1
US 2005/0285184 A1
US 2007/0048957 A1

US 2007/0163109 A1
Mar. 23, 2004
Feb. 1, 2005
Sep. 15, 2005
Dec. 29, 2005
Mar. 1, 2007 (filed
Aug. 31, 2006)
July 19, 2007 (filed

2 Throughout this opinion, we refer to (1) the Appeal Brief (Br.) filed August
17, 2010; and (2) the Examiner’s Answer (Ans.) mailed November 15, 2010.
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Dec. 29, 2005)

THE REJECTIONS
1. The Examiner rejected claims 1-3 under 35 U.S.C. § 103(a) as
unpatentable over Lee and Chen. Ans. 4-6.
2. The Examiner rejected claims 4-6 under 35 U.S.C. § 103(a) as
unpatentable over Lee, Chen, and Jung. Id. at 6-8.
3. The Examiner rejected claim 7 under 35 U.S.C. § 103(a) as
unpatentable over Lee, Chen, Jung, and Han. Id. at 8-9.
4. The Examiner rejected claims 15-18 and 20 under 35 U.S.C. § 103(a)
as unpatentable over Takiar, Lee, Chen, and Jung. Id. at 9-14.
5. The Examiner rejected claim 19 under 35 U.S.C. § 103(a) as
unpatentable over Takiar, Lee, Chen, Jung, and Han. Id. at 14-15.
6. The Examiner rejected claims 1-3 under 35 U.S.C. § 103(a) as
unpatentable over Jenne. Id. at 15-17.
7. The Examiner rejected claims 4 and 5 under 35 U.S.C. § 103(a) as
unpatentable over Jenne and Jung. Id. at 17-19.
8. The Examiner rejected claims 6 and 7 under 35 U.S.C. § 103(a) as
unpatentable over Jenne and Han. Id. at 19-20.
9. The Examiner rejected claims 15-17, 19, and 20 under 35 U.S.C.
§ 103(a) as unpatentable over Takiar, Jenne, and Han. Id. at 20-25.
10. The Examiner rejected claim 18 under 35 U.S.C. § 103(a) as
unpatentable over Takiar, Jenne, Han, and Jung. Id. at 25-26.

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OBVIOUSNESS REJECTIONS OVER LEE AND CHEN OR JENNE
Regarding representative claim 1, the Examiner finds that Lee
discloses all of the limitations recited in claim 1, except that “Lee fails to
expressly disclose where the separate silicon nitride layer is a low silicon-
rich nitride layer, wherein said separate low silicon-rich nitride layer
contains a lower silicon concentration than said silicon-rich nitride layer.”
Ans. 10 (emphasis omitted). Nevertheless, the Examiner finds that, in view
of Chen’s description of the range of the ratios of silicon to nitrogen in a low
or very low silicon-rich nitride layer, Lee discloses a layer having ratios
overlapping the range of the ratios of the low or very low silicon-rich nitride
layer. Id. at 11-12.
Alternatively, the Examiner finds that, in view of Appellants’
description of a “regular nitride layer” (Spec. 8:2-8), Jenne discloses or
renders obvious all of the limitations recited in claim 1. Ans. 21-22.
Appellants argue that neither Lee nor Jenne discloses or renders
obvious either that a silicon-rich nitride layer is situated over a bottom oxide
layer or that a separate low silicon-rich nitride layer situated over the silicon-
rich nitride layer, as recited in claim 1. Br. 8, 19-20. Further, according to
Appellants, neither Lee and Chen nor Jenne discloses or renders obvious that
the silicon concentration of the low silicon-rich nitride layer is lower than
that of the silicon-rich nitride layer. Id. at 8-9, 12, 20.
ISSUES
Under § 103(a), has the Examiner erred by finding that Lee and Chen,
collectively, or Jenne teach or suggest:
(1) “a silicon-rich nitride layer situated over said bottom oxide layer,”
as recited in claim 1? or
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(2) “a separate low silicon-rich nitride layer situated over said silicon-
rich nitride layer, wherein said separate low silicon-rich nitride layer
contains a lower silicon concentration than said silicon-rich nitride layer,” as
recited in claim 1?
ANALYSIS
1. Claim Construction.
We begin by construing the disputed limitations of claim 1 which
calls for, in pertinent part,
a silicon-rich nitride layer situated over said bottom oxide layer;
[and]
a separate low silicon-rich nitride layer situated over said
silicon-rich nitride layer, wherein said separate low silicon-rich
nitride layer contains a lower silicon concentration than said silicon-
rich nitride layer (emphases added).

In construing these limitations, we apply the broadest reasonable meaning of
the words in their ordinary usage, as those words would be understood by
one of ordinary skill in the art, taking into account any definitions supplied
by Appellants’ Specification. In re Morris, 127 F.3d 1048, 1054 (Fed. Cir.
1997).
In describing the silicon-rich nitride layer and the separate low
silicon-rich nitride layer, claim 1 recites that the silicon-rich nitride layer is
situated over the bottom oxide layer and that the separate low silicon-rich
nitride layer is situated over the silicon-rich nitride layer. Appellants do not
expressly define the term “over” in the claims or in the Specification.
Nevertheless, a pertinent definition of the preposition “over” is “above in
place or position.” RANDOM HOUSE WEBSTER’S COLLEGE DICTIONARY 940
(2nd Random House ed. 1999).
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We further note that the preamble of claim 1 includes the transitional
term “comprising.” “‘Comprising’ is a term of art used in claim language
which means that the named elements are essential, but other elements may
be added and still form a construct within the scope of the claim.”
Genentech, Inc. v. Chiron Corp., 112 F.3d 495, 501 (Fed. Cir. 1997)
(emphasis added). Thus, the scope of the language of this claim does not
preclude, for example, the inclusion of layers in addition to the bottom oxide
layer, the silicon-rich nitride layer, and the separate low silicon-rich nitride
layer.
In the Specification, Appellants describe, for example, that “silicon-
rich nitride layer 210 can be formed over bottom oxide layer 208” (Spec.
11:13-14 (emphasis added)). Appellants do not direct attention to anything
in the Specification showing that “over” mandates direct contact. See
Morris, 127 F.3d at 1056 (“It is the applicant’s burden to precisely define
their invention, not the PTO’s.”). Thus, consistent with the Specification
and the term’s plain meaning, we construe to term “over” to mean “above or
at a higher position than.” Therefore, the various layers of Appellants’
recited structure may be above or at a higher position than one another; this
may include, but is not limited to, layers that are “on,” i.e., in direct contact
with, one another.
We further note that Appellants do not expressly define the term
“silicon-rich nitride layer” or “low silicon-rich nitride layer.” Nevertheless,
referring to the embodiment depicted in Figure 2, Appellants describe that
“layer 212 can comprise an ordinary silicon nitride layer (also referred to
simply as ‘nitride’ in this application), instead of the low silicon-rich nitride
layer referred to in the earlier embodiment. However, in both embodiments,
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layer 210 comprises a silicon-rich nitride layer.” Spec. 7:1-4 (emphases
added). In addition, referring to Figure 3, Appellants describe that “bi-layer
plot 308 comprising a very low silicon-rich nitride (for example, a regular
nitride layer) over a silicon-rich nitride layer, bi-layer plot 310 comprising a
low silicon-rich nitride layer over a silicon-rich nitride layer, and single
layer plot 312, comprising only silicon-rich nitride layer.” Id. at 8:2-8
(emphases added). Thus, we interpret a very low silicon-rich nitride layer to
correspond to an ordinary or regular silicon nitride layer, and we construe a
“low silicon-rich nitride layer” to include a very low silicon-rich nitride
layer, as well as layers that contain more silicon than a very low silicon-rich
nitride layer, but less than a silicon-rich nitride layer. Therefore, these layers
are defined by their relative silicon contents; and, in view of the Figure 3, we
conclude that a low silicon-rich nitride layer encompasses very low silicon-
rich nitride layers. Ans. 28.
2. Lee and Chen.
Referring to Lee’s Figure 7, the Examiner finds that Lee depicts a first
oxide layer 115, which corresponds to the bottom oxide layer, on a
semiconductor substrate. Ans. 4 (citing Lee, ¶ [0115]). Further, Lee depicts
a silicon nitride layer 120 comprising a silicon nitride layer 122 on first
oxide layer 115 and a silicon-rich nitride layer 124 on silicon nitride layer
122. Id. (citing Lee, ¶ [0128]); see also Lee, ¶ [0118]. Lee further teaches
that a third silicon nitride layer, formed in the same manner as silicon nitride
layer 122, may be formed on silicon-rich nitride layer 124. Id. (citing Lee,
¶¶ [0123], [0130]).
Lee describes that silicon-rich nitride layer 124 may have a
composition ratio of silicon with respect to nitrogen “in a range of about
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0.85 to about 1.5, and preferably in a range of about 0.9 to about 1.3.” Lee,
¶ [0129]. Further, Lee describes that silicon nitride layer 122 may have a
composition ratio of silicon with respect to nitrogen “in a range of about 0.7
to about 0.85, and preferably in a range of about 0.7 to about 0.8.” Id. at ¶
[0128]. Because Lee describes that the third silicon nitride layer situated
over silicon-rich nitride layer 124 may be formed using substantially the
same method as that of silicon nitride layer 122 (id. at ¶ [0123]), the
Examiner concludes that the third silicon nitride layer also may have a
composition ratio of silicon with respect to nitrogen in a range of about 0.7
to about 0.85, and preferably in a range of about 0.7 to about 0.8 (Ans. 4-5).
We agree.
Referring to Chen’s Figure 1, Chen depicts a graded trapping layer
104, in which the composition ratio of silicon with respect to nitrogen
decreases from the bottom to the top of the layer. Chen, ¶ [0040]. Chen
teaches that “[t]he silicon/nitrogen compositional ratio x/y of silicon-rich
silicon nitride is larger than ¾[, i.e., 0.75], while the silicon/nitrogen
compositional ratio x/y of nitrogen-rich silicon nitride is smaller than ¾[,
i.e., 0.75]. In the middle portion of the graded silicon nitride layer 112, the
silicon/nitrogen compositional ratio x/y is about ¾[, i.e., 0.75].” Id.
(emphases added). Thus, the Examiner concludes that the transition
between a silicon-rich composition and a nitrogen-rich composition occurs
at a composition ratio of 0.75. Ans. 4-5. We agree.
Consequently, the Examiner finds that Lee’s third silicon nitride layer,
having a composition ratio in a range of 0.7 to about 0.85, and preferably in
a range of about 0.7 to about 0.8, demonstrates a range which overlaps a
composition ratio, e.g., 0.75 < ratio ≤ 0.8, of a low or very low silicon-rich
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nitride layer. Id. Again, we agree. Thus, the Examiner concludes that Lee
and Chen, collectively, disclose a bottom oxide layer (i.e., first oxide layer
115), a silicon-rich nitride layer (i.e., silicon-rich nitride layer 124) over the
bottom oxide layer, and a low silicon-rich nitride layer (i.e., the third silicon-
nitride layer) over the silicon-rich nitride layer, wherein the silicon
concentration of the low silicon-rich nitride layer (e.g., about 0.7 to about
0.8) is lower than that of the silicon-rich nitride layer (e.g., about 0.9 to
about 1.3).
Appellants argue that Lee does not disclose a silicon-rich layer
situated over a bottom oxide layer. Br. 8. Further, Appellants argue that,
unlike the recited structure of claim 1, Lee describes a silicon-rich nitride
layer “sandwiched” between two silicon nitride layers. Id. at 9-10. In view
of Lee’s disclosure, as discussed above; the construction of the term “over”;
and the breadth imparted to claim 1 by the use of the transitional term:
“comprising,” we are not persuaded by this argument.
Further, Appellants argue that Lee does not disclose a separate low
silicon-rich nitride layer situated over the silicon-rich nitride layer, wherein
the separate low silicon-rich nitride layer contains a lower silicon
concentration than the silicon-rich nitride layer (id. at 10-11) and that Chen
fails to supply this missing low silicon-rich nitride layer (id. at 11). Initially,
we note that Chen is relied upon to teach a range of composition ratios for a
silicon-rich layer, not to supply the low silicon-rich nitride layer. See Ans.
4. Moreover, Appellants argue that Lee does not describe silicon nitride
layer 122 or the third silicon nitride layer as “silicon-rich.” Id. at 11-12.
Nevertheless, Chen describes composition ratios greater than 0.75 as silicon-
rich. Chen, ¶ [0040]; see also Ans. 5. Thus, Appellants argue that Lee
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contradicts Chen. Br. 12. The Examiner explains, however, that Lee’s
ranges for silicon nitride layer 122 or the third silicon nitride layer “overlap”
the range understood in the art as a “silicon-rich” range. Ans. 28-29.
Therefore, we are not persuaded that the terminology of Lee and that of
Chen describing “silicon-rich” are contradictory, and we are persuaded that
Lee and Chen teach the low silicon-rich nitride layer, as recited in claim 1.
3. Jenne.
Referring to Jenne’s Figure 5F, the Examiner finds that Jenne
describes a bottom oxide layer, e.g., tunnel oxide 500, situated over a
semiconductor substrate, e.g., substrate 502. Ans. 16. Further, Jenne
describes that “[a] layer of silicon nitride 510 has been formed over silicon-
rich silicon nitride layer 508. A silicon nitride layer 510 may have a lower
percentage of silicon than a silicon-rich silicon nitride layer 508.” Jenne,
col. 7, l. 65-col. 8, l.1 (emphases added). Thus, Jenne discloses that a layer
with a lower silicon to nitrogen ratio is formed over a silicon-rich nitride
layer.
Although Jenne does not expressly describe silicon-nitride layer 510
as a silicon-rich nitride layer (see Br. 20), the Examiner notes that
Appellants describe an “ordinary” or “regular” silicon nitride layer as
including a very low silicon-rich nitride layer. Ans. 16 (citing Spec. 8:5-6);
see also Spec. 7:1-4 (describing “ordinary silicon nitride layer”). Thus,
because Jenne describes layer 510 as having a lower silicon percentage than
layer 508, and because Appellants do not distinguish between “silicon-rich,”
“low silicon-rich,” and “ordinary” or “regular” silicon nitride layers; Jenne
satisfies the disputed limitations. In any event, the Examiner concludes that
the modification of Jenne’s layer 510 to be a low silicon-rich nitride layer is
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a matter of design choice or optimization based on routine experimentation.
Ans. 16-17; Cf. Spec. 9:1-4; Fig. 3 (depicting silicon-rich single layer plot
312).3 The Examiner also notes that employing two silicon nitride layers
with different concentrations alters the charge storing capacity and the
ability to erase electrons stored in the charge-trapping dielectric. See Ans. 29
(citing Lee, ¶ [0030]). To the extent that Jenne does not expressly disclose a
low silicon-rich nitride layer, as recited in claim 1; given Appellants’
description of “ordinary” and “regular” silicon nitride layers, we agree with
the Examiner that the proposed modification would have been obvious to a
person of ordinary skill in the relevant art, for example, in order to modify
the charge storing capacity or charge-trapping characteristics of the device.
As argued above with respect to Lee and Chen, Appellants now argue
that Jenne does not disclose a silicon-rich layer situated over a bottom oxide
layer. Br. 19-20. Further, Appellants argue that, unlike the recited structure
of claim 1, Jenne describes a silicon-rich nitride layer “sandwiched” between
two silicon nitride layers. Id. In view of Jenne’s disclosure, as discussed
above; the construction of the term “over”; and the breadth imparted to
claim 1 by the use of the transitional term: “comprising,” we are not
persuaded by this argument.
For the foregoing reasons, Appellants have not persuaded us of error
in the rejections of independent claim 1, based on Lee and Chen or Jenne,

3 See also KSR Int’l. Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007) (“When
there is a design need or market pressure to solve a problem and there are a
finite number of identified, predictable solutions, a person of ordinary skill
has good reason to pursue the known options within his or her technical
grasp.”).
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and of claims 2 and 3, not separately argued with particularity. Therefore,
we sustain the obviousness rejections of these claims.

OBVIOUSNESS REJECTIONS OVER LEE AND CHEN OR JENNE IN
COMBINATION WITH JUNG AND/OR HAN
Although the Examiner rejects claims 4-7 under § 103(a) as
unpatentable over Lee and Chen or Jenne, in combination with Jung and/or
Han, each of these claims depends, directly or indirectly, from independent
claim 1; and Appellants do not argue these claims separately from claim 1,
with particularity. Br. 12-13 (stating that neither Jung nor Han rectifies the
alleged deficiencies in the combination of Lee and Chen); 21-22 (stating that
neither Jung nor Han rectifies the alleged deficiencies in Jenne). For the
same reasons that Appellants have not persuaded us of error in the rejections
of independent claim 1, discussed above, we are not persuaded of error in
the rejections of dependent claims 4-7. Thus, we sustain the obviousness
rejections of these claims.

OBVIOUSNESS REJECTIONS OVER TAKIAR IN COMBINATION
WITH LEE AND CHEN OR JENNE, AND FURTHER IN
COMBINATION WITH JUNG AND/OR HAN
The Examiner rejects claims 15-20 under § 103(a) as unpatentable
over Takiar in combination with Lee and Chen or Jenne, and further in
combination with Jung and/or Han. Independent 15 recites an electronic
system comprising at least one flash memory cell comprising the layers
recited in independent claim 1. Br. 14 (“Independent claim 15 specifies a
flash memory cell including similar limitations as the structure specified in
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independent claim 1.”); see also Br. 23. As discussed above with respect to
claim 1, Appellants argue that neither Lee and Chen nor Jenne disclose the
similar limitations of claim 1 that are contained in claim 15. Id. at 13-15,
22-24. For the reasons set forth above with respect to claim 1, we are not
persuaded by these arguments.
Further, Appellants argue that neither Jung (id. at 15-16) nor Han (id.
at 24) discloses the similar limitations of claim 1 that are contained in claim
15 and that allegedly are not supplied by Lee and Chen or Jenne. Initially,
we note that the Examiner does not rely on Jung and/or Han to supply those
limitations. Ans. 10-12, 21-22. Moreover, because we conclude that the
Examiner demonstrates that Lee and Chen or Jenne teach or suggest the
limitations of claim 1, we also conclude that the similar limitations of claim
15 are taught or suggested by these references.
In addition, Appellants argue that the Examiner fails to demonstrate
any reasoning with rational underpinning to combine Takiar with Lee and
Chen or with Jenne, in combination with other references, to achieve the
recited inventions. Br. 16, 24. In particular, Appellants argue that Takiar
discloses “a strip on which a plurality of integrated circuit packages may be
fabricated with a plurality of process tools.” Id. at 14. Appellants argue that
Takiar discloses flash memory storage cards fabricated as system-in-a-
package (SIP) or multichip modules (MCM) and that their flash memory cell
is fabricated in a different manner. Id. Thus, Appellants argue that a person
of ordinary skill in the art would not have sufficient reason to combine
Takiar with Lee and Chen or with Jenne, and the other cited references, to
achieve the recited inventions. Id.
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As the Examiner states, however, although Takiar fails to expressly
disclose Appellants’ flash memory cell structure, Takiar discloses a die
comprising a circuit board that comprises flash memory cells. Ans. 29; see
also Takiar, ¶¶ [0004]-[0006] (describing flash memory storage cards
fabricated by SIP and MCM). The Examiner concludes that a person of
ordinary skill in the relevant art at the time of the invention “would have
readily recognized the desirability and advantages of modifying Takiar by
employing the well known or conventional features of flash memory device
fabrication/structure, such as that displayed by Lee and Chen [or Jenne,] in
view Jung [or Han].” Id. As the U.S. Supreme Court explains,
If a person of ordinary skill can implement a predictable variation, §
103 likely bars its patentability. For the same reason, if a technique
has been used to improve one device, and a person of ordinary skill in
the art would recognize that it would improve similar devices in the
same way, using the technique is obvious unless its actual application
is beyond his or her skill.

KSR, 550 U.S. at 417 (emphasis added). Thus, we conclude that the
Examiner demonstrates sufficient reason to combine the teachings of these
references supported by articulated reasoning with some rational
underpinning to justify the obviousness conclusions.
For reasons discussed above, Appellants have not persuaded us of
error in the rejections of independent claim 15 or of dependent claims 16-20,
which Appellants do not argue separately with particularity. Br. 16, 17, 25.
Thus, we are not persuaded of error in the rejections of claims 15-20.
Therefore, we sustain the obviousness rejections of these claims.

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CONCLUSION
The Examiner did not err in rejecting claims 1-7 and 15-20 under
§ 103(a).

DECISION
The Examiner’s decision rejecting claims 1-7 and 15-20 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)(iv).

AFFIRMED

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