Ex Parte Teo et al

Patent Trial and Appeal Board

May 6, 2014

11333399 (P.T.A.B. May. 6, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte JOCELYN WEI-YEE TEO, CHI-CHUN CHEN,
and SHIH-CHANG CHEN
____________

Appeal 2012-000687
Application 11/333,399
Technology Center 2800
___________

Before ADRIENE LEPIANE HANLON, CATHERINE Q. TIMM and
JAMES C. HOUSEL, Administrative Patent Judges.

HOUSEL, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2012-000687
Application 11/333,399

2
Appellants1 seek our review under 35 U.S.C. § 134 of the Examiner’s
decision finally rejecting claims 9-19, 21, 22, 25-29, and 31-33. We have
jurisdiction over the appeal under 35 U.S.C. § 6(b).
We AFFIRM-IN-PART.2

STATEMENT OF THE CASE
The invention relates to a method of forming metal oxide
semiconductor (MOS) devices using hydrogen annealing. Spec. ¶ [0007].
Appellants disclose, in reference to Figure 7A reproduced below, due to
hydrogen annealing, surface 40 in the active region 100 has a convex surface
or a substantially rounded surface. Id. at ¶ [0024]. According to Appellants,
the curvature “introduces beneficial strain to the channel region of the MOS

1 Appellants identify the Real Party in Interest in this appeal as Taiwan
Semiconductor Manufacturing Company, Ltd.
2 Our decision refers to Appellants’ Brief (App. Br.) filed May 20, 2011, the
Examiner’s Answer (Ans.) mailed July 29, 2011, and Appellants’ Reply
Brief (Reply Br.) filed September 28, 2011.

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Appeal 2012-000687
Application 11/333,399

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substantially the entirety of the top surface of the second active
region forms a convex surface with a curvature; and

forming a second gate dielectric over the semiconductor
substrate in the second active region.

App. Br. A1, Claims App’x.
Rejections
The Examiner maintains, and Appellants request review of, the
following rejections under 35 U.S.C. § 103(a):
(a) claims 9-11, 13-14, 16-18, 21-22, 25, and 31 over Horita3 in view
of Yamamoto4;
(b) claim 12 over Horita and Yamamoto, further in view of Yang5;
(c) claim 15 over Horita and Yamamoto, further in view of Lee6;
(d) claim 33 over Horita and Yamamoto, further in view of
Nakamura7;
(e) claims 19, 26, 28-29, and 32 over Yamamoto in view of Lee; and
(f) claim 27 over Yamamoto and Lee, further in view of Horita.
With respect to Rejection (a), Appellants confine their arguments to
the rejection of independent claims 9 and 22. In accordance with 37 C.F.R.
§ 41.37(c)(1)(vii), we select claims 9 and 22 as representative for resolving
the issues arising for Rejection (a). Rejections (b) through (d) stand or fall
with the decision with regard to Rejection (a) as Appellants do not advance
any additional arguments directed to those rejections. With respect to

3 US 2002/0005529 A1, published January 17, 2002.
4 US 2006/0001108 A1, published January 5, 2006.
5 US 2005/0167750 A1, published August 4, 2005.
6 US 2006/0008961 A1, published January 12, 2006.
7 US 2005/0062080 A1, published March 24, 2005.
Appeal 2012-000687
Application 11/333,399

5
Rejection (e), Appellants confine their arguments to the rejection of claim
19. We, therefore, select claim 19 as representative. Rejection (f) stands or
falls with the decision with regard to Rejection (e).

ANALYSIS
Rejection for Claims 9 and 22 over Horita and Yamamoto
The Examiner finds Horita discloses a method of forming a
semiconductor structure comprising forming trench isolation regions
extending from the top into the semiconductor substrate to define one or
more active regions; forming a gate dielectric over the semiconductor
substrate in the active regions; performing a hydrogen anneal on the
semiconductor substrate so that the cross-sectional shape of the upper edge
portion of the active region is formed into a circular arc; and forming a gate
dielectric (gate insulating film) over the semiconductor substrate in the
active region. Ans. 4-5. The Examiner acknowledges that Horita lacks the
teaching of first and second active regions and, therefore, that the hydrogen
annealing is performed while the entire top surface in the second active
region is exposed. Id. at 5 (emphasis added). 8 However, the Examiner finds
Horita provides for multiple active regions in the recitation of “at least one
active region” (Horita, ¶ [0037]), and in other embodiments (Horita, ¶¶
[0048], [0050], [0052]). Id.
The Examiner looks to the teaching of Yamamoto for an explicit
teaching of first and second active regions separated by trench isolation

8 We note claim 9 does not require that hydrogen annealing be performed on
the second active region only.
Appeal 2012-000687
Application 11/333,399

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regions, wherein the hydrogen anneal is performed while the entire top
surface of the semiconductor substrate in the second active region is
exposed. Id. at 5-6. The Examiner concludes it would have been obvious to
one of ordinary skill in the art to provide Horita with first and second active
regions such that the hydrogen annealing is performed while the entire top
surface in the second active region is exposed to allow field effect transistors
with different properties to be formed. Id. at 6. The Examiner finds the
convex curvature of the surface of the second active region is a passive
(inherent) result of the claimed steps, which are disclosed by both Horita and
Yamamoto. According to the Examiner, “[i]f the claimed active steps are all
the same, then the shape should be the same.” Id. Alternatively, the
Examiner determines that “if the shape is not the same, then there is some
random variation in possible resultant shapes that would be discovered
during routine experimentation and optimization.” Id.
Appellants argue that Horita fails to explicitly or inherently disclose
the claimed features of claims 9 and 22. App. Br. 13-20. Particularly,
Appellants argue that Horita does not teach “substantially the entirety of the
top surface of the second active region” either forms a convex surface with a
curvature (claim 9), or is rounded (claim 22). Id. at 13. Appellants assert
that Horita only teaches a planarized portion between two upper edge
portions that are “‘formed into a circular arc’” or “formed into a rounded
cross-sectional shape having a radius of curvature” as shown in Fig. 11. Id.
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Application 11/333,399

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position that in the absence of a definition in the Specification, the term
“substantially” has the ordinary dictionary meaning of “being largely but
not wholly that which is specified.” Id. at 25. As such, the Examiner finds
Horita’s Figure 24 shows that “‘most but not all’” of the upper surface of
PP1 forms a convex surface with a curvature, or is rounded. Id. at 26. On
the other hand, citing Phillips v. AWH Corp., 415 F.3d 1301 (Fed. Cir.
2005), Appellants argue that the Examiner fails to consider “substantially” in
a manner consistent with the disclosure of the Specification. Reply Br. 5-6.
According to Appellants, the Specification describes surface 41 of Fig. 7A
as “substantially flat, ‘although a slight curvature may exist.’” Id. at 6,
citing Spec. ¶ [0026]. Therefore, Appellants contend a skilled artisan would
understand the claimed term “substantially” allows for a slight flatness, but
not Horita’s significant intentionally planarized portion between two upper
edge portions. Id.
We begin, appropriately, with the claim’s words. See Amazon.com,
Inc. v. Barnesandnoble.com, Inc., 239 F.3d 1343, 1351 (Fed. Cir. 2001)
(“Only when a claim is properly understood can a determination be made . . .
whether the prior art anticipates and/or renders obvious the claimed
invention.”); In re Donaldson Co., 16 F.3d 1189, 1192 (Fed. Cir. 1994).
During examination, claim terms are given their broadest reasonable
construction consistent with the specification. In re ICON Health & Fitness,
Inc., 496 F.3d 1374, 1379 (Fed. Cir. 2007). In general, words used in a
claim are accorded their ordinary and customary meaning. Honeywell Int’l
Inc. v. Universal Avionics Sys. Corp., 488 F.3d 982, 992 (Fed. Cir. 2007).
Under a broadest reasonable interpretation, words of the claim must be given
their plain meaning, unless such meaning is inconsistent with the
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Application 11/333,399

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specification. However, limitations from the Specification must not be read
into the claims. Sjolund v. Musland, 847 F.2d 1573, 1581 (Fed. Cir. 1988)
(“[W]hile it is true that claims are to be interpreted in light of the
specification and with a view to ascertaining the invention, it does not follow
that limitations from the specification may be read into the claims.”); see
also In re Am. Acad. of Sci. Tech. Ctr., 367 F.3d 1359, 1369 (Fed. Cir. 2004)
(“We have cautioned against reading limitations into a claim from the
preferred embodiment described in the specification, even if it is the only
embodiment described, absent clear disclaimer in the specification.”)
Looking to Appellants’ Specification, the Examiner finds no
description of the limits on how much the top surface must form a convex
surface with a curvature or is rounded. Ans. 25. We note the Specification
only discloses that “the surface 40 in the active region 100 has a convex
surface with curvature, as illustrated in Figure 7A. In one exemplary
embodiment, the convex surface is substantially rounded . . .” Spec. ¶
[0024]. In addition, the Specification teaches that “[d]epending on the
widths of the isolation separation regions or the active regions, this curvature
or the extent of the curvature varies.” Id. Moreover, the Specification
teaches
The roundness of the surface 40 of the region 100 is
affected by various factors, such as the composition of the
semiconductor substrate 20 and the length L of the active
region 100. Different temperatures, hydrogen pressures and
anneal durations may be required to form rounded surface 40
with a desired curvature. One skilled in the art can find suitable
temperatures, pressures and anneal durations through routine
experiments.

Appeal 2012-000687
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Id. at ¶ [0025]. We further note that the factors and conditions under which
the curvature of surface 40 is achieved in Fig. 7A are not described. The
“desired curvature” is also not further defined in the Specification. We
conclude that the claim recitation is sufficiently broad to encompass the
preferred embodiment of Fig. 7A and any “desired curvatures,” including
the convex surface of PP1 having a curvature shown in Horita’s Fig. 24.
Such an interpretation is consistent with the disclosure of Appellants’
Specification.
Since we are satisfied that Horita’s Figure 24 and attendant written
description meets the claim recitation that substantially the entirety of the
top surface of the active region forms a convex surface with a curvature
(claim 9) and is rounded (claim 22), we need not reach the Examiner’s
alternative positions that Horita either inherently meets this recitation or
would meet this recitation through routine optimization, nor Appellants’
arguments directed against these alternative positions. Accordingly,
Appellants have not shown reversible error in the Examiner’s rejection. We
will sustain the Examiner’s Section 103 rejections of claims 9 and 22, and
their dependent claims, over Horita and Yamamoto, alone or further in view
of any of Yang, Lee and Nakamura.

Rejection for Claim 19 over Yamamoto and Lee
The Examiner finds that Yamamoto (Fig. 5A-G) discloses a method
of forming a semiconductor structure comprising the steps of forming trench
isolation regions 2 in the semiconductor substrate, wherein the trench
isolation regions define a first active region (high voltage region) and a
second active region (low voltage region); forming a first gate dielectric 4
Appeal 2012-000687
Application 11/333,399

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over the semiconductor substrate in the first active region; performing a
hydrogen anneal (rapid thermal hydrogen anneal or RTH) on the
semiconductor substrate in an ambient containing substantially pure
hydrogen, wherein the second active region forms a round surface; and
forming a second gate dielectric 6 over the round surface and a second gate
electrode 7 over the second gate dielectric. Ans. 16-19. The Examiner finds
that the “round surface having a curvature” limitation is met by Yamamoto’s
disclosure that RTH results in corners being “‘more rounded’” and “‘the
flatness of the active region 3 is increased.’” Id. at 18. Further, the
Examiner finds Yamamoto’s process steps and mechanism of shape change
(diffusion of silicon atoms) are the same as in the claimed method, the
results (the shape) should be the same. Id. Alternatively, the Examiner
finds that though the shape may be slightly different, variations in the
resultant shape would have been discovered during routine experimentation
and optimization. Id. at 18-19. The Examiner acknowledges that
Yamamoto fails to disclose that the hydrogen annealing is performed after
forming the first gate electrode, but finds that Lee teaches hydrogen
annealing after forming the first gate electrode. Id. at 19.
Appellants argue that Yamamoto does not explicitly or inherently
disclose the “round surface having a curvature” or the same process steps as
recited in the claims. App. Br. 21-22, 24. Rather, Appellants urge that
Yamamoto describes a flat portion between rounded corners as shown in
Fig. 5E (depicted below). Id. at 22.
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Figure 5E of Yamamoto, depicting a stage in forming a semiconductor
device
Appellants argue that Yamamoto in fact teaches away from the claimed
invention in stating that as a result of RTH, “flatness of the active region 3 is
increased and its corners are rounded.” App. Br. 12; Yamamoto ¶ [0041].
Further, Appellants argue that Yamamoto does not recognize the desire for a
rounded surface to improve mobility or describe any result-effective
variables that would motivate experimentation and optimization by the
ordinary artisan. App. Br. 24-25.
Appellants’ arguments are persuasive of reversible error. In the
rejection, the Examiner finds that the “round surface having a curvature”
limitation has been met because Yamamoto discloses RTH results in corners
being “more rounded” and “the flatness of the active region 3 is increased.”
The Examiner considers that if the flatness is “increased,” it is not flat. Ans.
18, 33. However, as noted by the Appellants, a surface of increased flatness
does not mean that it is a round surface. For example, as Appellants note,
the increased flatness may be a reduction in surface roughness. Reply Br.
12. The Examiner has failed to supply the requisite facts showing that
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Yamamoto explicitly or inherently discloses the claimed “rounded surface
having a curvature.”
The Examiner maintains that because Yamamoto and the claimed
process both perform a hydrogen anneal, the resultant shape would be the
same. Ans. 18, 36. However, the Examiner fails to direct us to any
evidence establishing that performing RTH under the conditions disclosed in
Yamamoto inherently produces “a round surface having a curvature that
extends from one trench isolation region across the entire second active
region to another trench isolation region” as claim 19 requires. As indicated
above the Examiner has not shown that one skilled in the art following the
teachings of Yamamoto would have arrived at the claimed invention, in the
absence of Appellants’ disclosure.
Accordingly, we will not sustain the Examiner’s Section 103 rejection
of claims 19, 26, 28-29, and 32 over Yamamoto and Lee. Further, with
regard to the rejection of claim 27, we note the Examiner does not rely on
Horita to remedy the deficiencies in the Yamamoto and Lee combination.
We therefore will not sustain the Examiner’s obviousness rejection of claim
27.

ORDER
Upon consideration of the record, and for the reasons given above and
in the Answer, it is
ORDERED that the decision of the Examiner rejecting under
35 U.S.C. § 103(a) claims 9-11, 13-14, 16-18, 21-22, 25, and 31 over Horita
in view of Yamamoto; claim 12 over Horita and Yamamoto, further in view
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14
of Yang; claim 15 over Horita and Yamamoto, further in view of Lee; and
claim 33 over Horita and Yamamoto, further in view of Nakamura is
affirmed; and
FURTHER ORDERED that the decision of the Examiner rejecting
under 35 U.S.C. § 103(a) claims 19, 26, 28-29, and 32 over Yamamoto in
view of Lee; and claim 27 over Yamamoto and Lee, further in view of
Horita is reversed.
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-IN-PART

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