Ex Parte Buettgen et al

Patent Trial and Appeal Board

Nov 28, 2016

12856701 (P.T.A.B. Nov. 28, 2016)

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.
12/856,701 08/16/2010 Bernhard Buettgen 40530-0013001 /
0154.0019
2690
26211 7590 11/30/2016
FISH & RICHARDSON P.C. (NY)
P.O. BOX 1022
MINNEAPOLIS, MN 55440-1022
EXAMINER
PIZARRO CRESPO, MARCOS D
ART UNIT PAPER NUMBER
2814
NOTIFICATION DATE DELIVERY MODE
11/30/2016 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
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PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte BERNHARD BUETTGEN, JONAS FELBER,
MICHAEL LEHMANN, and THIERRY OGGIER
Appeal 2014-003584
Application 12/856,701
Technology Center 2800
Before ADRIENE LEPIANE HANLON, CATHERINE Q. TIMM, and
JAMES C. HOUSEL, Administrative Patent Judges.
HOUSEL, Administrative Patent Judge.
DECISION ON APPEAL1
Pursuant to 35 U.S.C. § 134(a), Appellants2 appeal from the
Examiner’s decision finally rejecting claims 1—17 as unpatentable under 35
U.S.C. § 103(a). We have jurisdiction over the appeal under 35 U.S.C.
§ 6(b).
1 Our decision refers to the Specification filed August 16, 2010, Appellants’
Appeal Brief (Appeal Br.) filed September 30, 2013, the Examiner’s Answer
(Ans.) delivered November 27, 2013, and Appellants’ Reply Brief (Reply
Br.) filed January 27, 2014.
2 According to Appellants, the real party in interest is MESA IMAGING
AG. Appeal Br. 1.
Appeal 2014-003584
Application 12/856,701
We AFFIRM-IN-PART.
STATEMENT OF THE CASE
The invention relates to a demodulation pixel having a drift field
incorporating one or more charge transport and photo-sensitivity
enhancement mechanisms including 1) a buried channel, 2) a majority
carrier current, 3) a high-low junction, and 4) a graded/gradually doped
wafer structure. Spec. 118. Demodulation pixels have different fields of
applications including three-dimensional range imaging and fluorescence
lifetime imaging where higher in-pixel charge transport speed and optical
sensitivity lead to more accurate per-pixel measurements. Id. at 12. “A
common problem of. . . [prior] pixels is the slowness of the charge transport
through the semiconductor material which decreases significantly the
accuracy or quality of the in-pixel demodulation process.” Id. at 17.
Appellants disclose that the enhancement mechanisms outperform prior
demodulation pixels in charge transport speed and photo-sensitivity. Id. at |
18.
Independent claims 1 and 12, reproduced below from the Claims
Appendix to the Appeal Brief, are illustrative of the subject matter on appeal
(paragraphing added). The limitations at issue are italicized.
1. A demodulation pixel, comprising:
a semiconductor substrate;
a photo sensitive section in the semiconductor substrate
for converting light into charge carriers;
storage nodes for receiving the charge carriers;
a demodulation region for transferring the charge carriers
to the different storage nodes;
a majority carrier current through semiconductor
substrate and under the photosensitive section that directs the
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Application 12/856,701
charge carriers to the demodulation region.
12. A demodulation pixel, comprising:
a semiconductor substrate;
a photo sensitive section in the semiconductor substrate for
converting light into charge carriers;
storage nodes for receiving the charge carriers;
a demodulation region for transferring the charge carriers to the
different storage nodes;
a high-low junction underneath the photo sensitive section for
directing charge carriers generated in the photo sensitive section to a
surface of the semiconductor substrate for transfer to the
demodulation region.
Rejections
The following rejections under 35 U.S.C. § 103(a) are before us on
appeal:
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Application 12/856,701
A. Claims 1—4 and 6—9 as unpatentable over Nakashima3 and
Schwarte;4
B. Claim 5 as unpatentable over Nakashima and Schwarte, further
in view of Ichikawa;5 and
C. Claims 10-17 as unpatentable over Nakashima and Schwarte,
further in view of Sinha6 and Yang.7
ANALYSIS
Rejection A
Appellants argue claims 1—4 and 9 separately. However, as will
become clear within this decision, we need only address claim 1. The
dispositive issue raised by Appellants’ arguments against this rejection is
whether the Examiner reversibly erred in finding that the Nakashima device
as modified by Schwarte is inherently capable of forming a majority carrier
current through the semiconductor substrate and under the photosensitive
section. We answer this question in the affirmative and, therefore, will not
sustain the Examiner’s rejection.
3 Nakashima et al., US 2008/0048212 Al, published February 28, 2008
(“Nakashima”).
4 R. Schwarte, et al., “A new electrooptical mixing and correlating sensor:
Facilities and Applications of the Photonic Mixer Device (PMD),”
Proceedings of the SPIE — The International Society for Optical
Engineering, Vol. 3100, pp. 245—253 (1997) (“Schwarte”).
5 Ichikawa et al., US 2009/0278174 Al, published November 12, 2009
(“Ichikawa”).
6 Amitabha Sinha, et al., “Effect of Heavy Doping on the Properties of High-
Low Junction,” IEEE Transactions on Electron Devices, Vol. ED 25, No. 12,
pp. 1412—1414 (December 1978).
7 Yang et al., US 6,184,055 Bl, issued February 6, 2001 (“Yang”).
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The Examiner finds Nakashima teaches most aspects of the invention
except for a majority carrier current flowing between two majority carrier
nodes. Ans. 3^4. For this feature, the Examiner finds Schwarte teaches
forming two majority, p+-type carrier nodes at either end of a photosensitive
section so that the device can operate at high frequencies and low
modulation voltages. Id. at 4. Therefore, the Examiner concludes it would
have been obvious to form two majority, p+-type carrier nodes at either end
of Nakashima’s photosensitive section so that Nakashima’s device can
operate at high frequencies and low modulation voltages. Id.
In addition, the Examiner finds “the presence of a majority carrier
current through semiconductor substrate and under the photo sensitive
section is an inherent property of the device of Nakashima.” Id. at 6. The
Examiner finds these currents are known in the art as parasitic or leakage
currents, are present even when the pixels are inactive, and can influence
neighboring pixels. Id. As such, the Examiner finds Nakashima teaches
isolation regions and Schwarte teaches p+ carrier node regions (channel
stops). Id. The Examiner further finds Nakashima shows all the features of
the claimed invention in support of the finding that the majority carrier
current is an inherent property of Nakashima’s device. Id. at 7. As such, the
Examiner finds the inherent parasitic or leakage current in Nakashima’s
device is the majority carrier current. Id.
Appellants contend that Nakashima and Schwarte do not teach or
suggest every feature of the claim 1. Appeal Br. 6. In particular, Appellants
argue that Schwarte does not teach or suggest a majority carrier current
through the semiconductor substrate and under the photosensitive section to
direct charge carriers to a demodulation region. Id. Because Schwarte
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Application 12/856,701
teaches a combined photosensitive and demodulation region, Appellants
argue that there is no need for a majority carrier that directs the charge
carriers from a photosensitive section to a demodulation region. Id. at 6—7;
Reply Br. 3. Appellants further argue that Schwarte does not teach two
majority carrier nodes on either end of a photosensitive section between
which the majority carrier current flows. Appeal Br. 7.
Moreover, Appellants urge that the Examiner’s finding that
Nakashima inherently has a majority carrier current is inconsistent with the
Examiner’s earlier finding that Nakashima fails to teach “a majority carrier
current flowing between two majority carrier nodes.” Reply Br. 1—2.
Appellants also argue that it would not have been obvious to modify a
device to have a component that creates an undesirable function. In other
words, Appellants argue that it would not have been obvious to modify
Nakashima’s device, which the Examiner finds inherently has parasitic or
leakage currents, with the nodes as Schwarte teaches to enhance such
undesirable currents. Id. at 3.
Appellants’ arguments are persuasive of reversible error in both the
Examiner’s inherency finding as well as the finding that the combination of
Nakashima and Schwarte would provide a majority carrier current between
two majority carrier nodes. We first turn to the Examiner’s finding that
Nakashima inherently provides a majority carrier current because of the
inherent existence of parasitic or leakage currents and because Nakashima
teaches all the physical features of the claimed invention. In general, a
limitation is inherent “if it is the ‘natural result flowing from’ the explicit
disclosure of the prior art.” Schering Corp. v. Geneva Pharms., 339 F.3d
1373, 1379 (Fed. Cir. 2003) (quoting EliLilly & Co. v. Barr Labs., Inc., 251
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F.3d 955, 970 (Fed. Cir. 2001)). ‘“Inherency, however, may not be
established by probabilities or possibilities. The mere fact that a certain
thing may result from a given set of circumstances is not sufficient.’” In re
Oelrich, 666 F.2d 578, 581 (CCPA 1981) (quoting Ilansgirg v. Kemmer,
102 F.2d 212, 214 (CCPA 1939)). What is required is that the inherent
feature inevitably results from the disclosed steps. In re Montgomery, 677
F.3d 1375, 1380 (Fed. Cir. 2012).
The Examiner’s support for the presence of parasitic or leakage
current is the presence of isolation nodes 2 in Nakashima’s Figure 2. Ans. 6.
The Examiner finds such isolation nodes are present to control the effect of
such undesirable currents. Id. However, what is not clear and is the subject
of Appellants’ challenge to the Examiner’s inherency finding is whether
such parasitic currents necessarily result in a majority carrier current through
the semiconductor substrate and under the photosensitive section to direct
charge carriers to the demodulation region. The Examiner does not direct
our attention to any teaching that such parasitic currents direct charge
carriers in any particular direction, much less under the photosensitive
section to the demodulation region, nor do we find any.
As to the Examiner’s finding that the combination of Nakashima and
Schwarte provides a majority carrier current between two majority carrier
nodes on either end of the photosensitive section between which the majority
carrier current flows, we find Appellants’ arguments persuasive that the
combination would not provide a majority carrier current through the
semiconductor substrate and under the photosensitive section that directs the
charge carriers to a demodulation region. As Appellants assert (Appeal Br.
7), Schwarte’s p+ nodes in Figure 2(b) are isolated from other components
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(including a voltage source) via either a Si-oxide or Si3N4 insulation layer.
Accordingly, Schwarte does not create a majority carrier current that directs
charge carriers to a demodulation region. Moreover, Appellants assert
without dispute that Schwarte teaches a combined photosensitive and
demodulation region thereby negating any need for a majority carrier
current.
Accordingly, we will not sustain the Examiner’s obviousness rejection
as to claims 1—4 and 6—9.
Rejection B
Claim 5 depends from claim 1, via claim 4, and further requires a
funnel shaped depleted implantation region in the direction of the
demodulation region. The Examiner does not rely on Ichikawa to remedy
the above-discussed deficiencies in the combination of Nakashima and
Schwarte. Accordingly, we will not sustain the Examiner’s obviousness
rejection of claim 5 for the same reasons as given above.
Rejection C
Appellants argue claims 10, 12, and 17 as a group, each of which
recites a high-low junction under the photosensitive section for directing
charge carriers to a surface of the semiconductor substrate. The Examiner
does not rely on tertiary references to Sinha and Yang to remedy
deficiencies in the combination of Nakashima and Schwarte as applied to
claim 1. Thus, given the dependency of claims 10 and 11 on claim 1, we
will not sustain the Examiner’s obviousness rejection of claims 10 and 11
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for the same reasons as given above. We, therefore, need only address
claims 12 and 17.
The Examiner finds the combination of Nakashima and Schwarte fails
to teach forming a high-low junction underneath the photosensitive section
and wafer material having an interface with the semiconductor substrate
forming the junction. Ans. 5. Nonetheless, the Examiner finds Sinha
teaches providing a high-low junction underneath a photosensitive section to
increase current and improve performance. Id. In addition, the Examiner
finds Yang teaches forming a high-low junction between wafer material and
a semiconductor substrate to improve sensor array modulation transfer
function by reducing random diffusion of photoelectric charges. Id.
Therefore, the Examiner concludes it would have been obvious to provide
Nakashima’s device with a high-low junction formed by a wafer material
interface with the semiconductor substrate underneath the photosensitive
section to increase current, reduce random diffusion of charges, and improve
performance. Id. at 5—6.
Appellants argue that Sinha merely teaches a high-low junction at the
back of a solar cell rather than a high-low junction underneath the
photosensitive section for directing charge carriers to a surface of a
semiconductor substrate for transfer to a demodulation region. Appeal Br. 9.
Appellants further argue that Yang merely teaches reducing “miscollection”
of photogenerated charges and does not teach a high-low junction
underneath a photosensitive section to direct charge carriers generated in the
photosensitive section to a surface of the semiconductor substrate for
transfer to a demodulation region. Id. at 10. As such, Appellants contend
the Examiner’s proposed combination fails to teach or suggest a high-low
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Application 12/856,701
junction underneath the photo sensitive section for directing charge carriers
generated in the photo sensitive section to a surface of the semiconductor
substrate for transfer to the demodulation region. Id.
We do not find Appellants’ arguments persuasive of reversible error
in the Examiner’s obviousness rejection of claims 12 and 17. Initially, we
note that Appellants’ arguments merely address each of Sinha and Yang
individually, rather the combination as proposed by the Examiner. “Non­
obviousness cannot be established by attacking references individually
where the rejection is based upon the teachings of a combination of
references. . . . [The reference] must be read, not in isolation, but for what it
fairly teaches in combination with the prior art as a whole.” In re Merck &
Co., Inc., 800 F.2d 1091, 1097 (Fed. Cir. 1986). In this case, Appellants do
not address the obviousness of providing a high-low junction underneath
Nakashima’s photosensitive section nor the Examiner’s reasoning for doing
so.
Further, while Appellants contend that the applied references fail to
teach or suggest a high-low junction underneath the photosensitive section
for directing charge carriers generated in the photosensitive section to a
surface of the semiconductor substrate for transfer to the demodulation
region, the Examiner finds without dispute that, given that the proposed
combination provides the structure of the claimed device, the ability of the
junction to direct charge carriers from the photo sensitive section to a
surface of the substrate for transfer to the demodulation region is an
inherent property of the combination device. Ans. 8. Appellants have not
provided any persuasive reasoning or evidence establishing otherwise.
Indeed, once a high-low junction is provided below the photosensitive
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section for preventing drift or diffusion of charge carriers further into the
substrate, it is reasonable to expect that these charge carriers will be directed
away from the junction and toward a surface of the semiconductor substrate
for transfer to the demodulation region.
Accordingly, we will sustain the Examiner’s obviousness rejection of
claims 12 and 17. Because Appellants do not separately argue claims 13—
15, these claims fall with claim 12 from which they depend.
Appellants next argue that the Examiner has made no findings in
support of the rejection of claim 16, which further requires a non-uniform
doping profile in the photosensitive section for generating a lateral drift field
to transfer charges to the demodulation region. Appeal Br. 10. We agree.
We are unable to identify any particular Examiner finding in either the
rejections or the response to arguments directed to claim 16 or a non-
uniform doping profile. Nor are we able to find any teaching or suggestion
in the Examiner’s proposed combination for providing a non-uniform doping
profile in the photosensitive section. We do not sustain the Examiner’s
obviousness rejection of claim 16.
CONCLUSION
The Section 103 rejections of claims 1—11 and 16 are not sustained,
whereas the Section 103 rejection of claims 12—15 and 17 is sustained.
DECISION
Upon consideration of the record, the decision of the Examiner
rejecting claims 1—4 and 6—9 under 35 U.S.C. § 103(a) as unpatentable over
Nakashima and Schwarte is reversed',
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rejecting claim 5 under 35 U.S.C. § 103(a) as unpatentable over
Nakashima and Schwarte, further in view of Ichikawa is reversed', and
rejecting claims 10-17 under 35 U.S.C. § 103(a) as unpatentable over
Nakashima and Schwarte, further in view of Sinha and Yang, is reversed as
to claims 10, 11, and 16, and affirmed as to claims 12—15 and 17.
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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