Ex Parte Giles et al

Patent Trial and Appeal Board

Jan 30, 2018

12618546 (P.T.A.B. Jan. 30, 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.
12/618,546 11/13/2009 Frederick Perry Giles 16483.0614US01/MAXM-0614 6863
99900 7590 02/01/2018
Advent/Maxim
The Advent Building
17838 Burke Street
Suite 200
Omaha, NE 68118
EXAMINER
MAI, ANH D
ART UNIT PAPER NUMBER
2829
NOTIFICATION DATE DELIVERY MODE
02/01/2018 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):
u spto @ adventip .com
sloma@adventip.com
Boumstein @ adventip.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL
AND APPEAL BOARD
Ex parte FREDERICK PERRY GILES, JOEL M. McGREGOR,
and STEPHEN MCCORMACK
Appeal 2017-002610
Application 12/618,546
Technology Center 2800
Before MARKNAGUMO, MICHAEL P. COLAIANNI, and
CHRISTOPHER C. KENNEDY, Administrative Patent Judges.
COLAIANNI, Administrative Patent Judge.
DECISION ON APPEAL
Appeal 2017-002610
Application 12/618,546
Appellants appeal under 35 U.S.C. § 134 the final rejection of claims
1—3, 6, 7, 9, and 10. We have jurisdiction over the appeal pursuant to
35 U.S.C. § 6(b).
We AFFIRM.
The appeal is directed to a power transistor having reduced gate
charge (Spec. 1:4—6; claim 1).
Claim 1 is illustrative:
1. A power transistor comprising:
a doped substrate comprising a doped source region in the doped
substrate, a doped body region disposed immediately adjacent to the doped
source region, a merged contact disposed over the dope source region and
the doped body region for shorting the doped source region and the doped
body region, a doped bridge region in the doped substrate, a first
controllable channel region, and a second controllable channel region within
a first doped region, a doped drain region in the doped substrate and a
transition region within a second doped region, and a trench within the
second doped region, wherein the doped source region, the doped drain
region, and the doped bridge region are doped the same type as the second
doped region, further wherein the trench is formed in the substrate and the
trench is filled with field oxide, further wherein the first controllable channel
region is positioned between the doped source region and the doped bridge
region, the second controllable channel region is positioned between the
doped bridge region and the transition region, the transition region is
positioned between the second controllable channel region and the trench,
and the trench is positioned between the transition region and the doped
drain region;
a gate oxide layer positioned on a first surface of the substrate;
a first gate positioned on the gate oxide layer and over the first
controllable channel region, the first gate configured to control operation of
the first controllable channel region;
a second gate positioned on the gate oxide layer and over the second
controllable channel region, the transition region, and a portion of the trench,
2
Appeal 2017-002610
Application 12/618,546
wherein the first gate is separated from the second gate such that at least a
portion of the doped bridge region is uncovered by both the first gate and the
second gate, the second gate configured to control operation of the second
controllable region; and
an insulating oxide structure disposed over and covering the first gate,
the second gate, and the trench,
wherein the doped bridge region separates the first controllable
channel region from the second controllable channel region.
(emphasis added to show disputed limitations).
Appellants appeal the following rejection:
Claims 1—3, 6, 7, 9, and 10 are rejected under 35 U.S.C. § 103(a) as obvious
over Hodel (US 2009/0140372 Al, published Jun. 4, 2007) in view of Kunz
(US 2004/0256692 Al, published Dec. 23, 2004) and Tanaka (US
2009/0114987 Al, published May 7, 2009).
Appellants argue the claims as a group (App. Br. 10, 15). We select
claim 1 as representative of the group. 37 CFR § 41.37(c)(l)(iv).
FINDINGS OF FACT & ANALYSIS
Appellants argue that the Examiner’s reason for combining Kunz’s
doping of the source, drain and bridge region having the same dopant-type
(e.g., P+) with Hodel’s transistor to reduce off-state leakage is faulty (App.
Br. 11, 13). Appellants argue that Kunz teaches that the composite transistor
structure in Kunz reduces off-state leakage currents, not the doping of the
source, drain and bridge being the same (App. Br. 13). Appellants contend
that the modification of Hodel’s transistor with Kunz’s composite transistor
would have frustrated the purpose of Hodel’s transistor arrangement, where
3
Appeal 2017-002610
Application 12/618,546
transistors are arranged in different positional relationships to one another
(App. Br. 13, 14).
The Examiner finds that Hodel teaches the subject matter of claim 1
except for the following three limitations: (1) explicitly disclosing that the
doped source region, the doped drain region, and the doped bridge region are
doped the same type as the second doped region, (2) a merged contact
disposed over the doped source and the doped body regions, and (3) an
insulating oxide structure disposed over the gates and the field oxide (Final
Act. 2-4). The Examiner finds that Tanaka teaches the missing limitations
(2) and (3) and concludes that it would have been obvious to modify Hodel’s
transistor structure in light of Tanaka’s teachings to provide an electrical
contact to both regions that is simplified that provides interconnection while
protecting the semiconductor device (Final Act. 6). Appellants do not
dispute the Examiner’s findings and conclusion with regard to the
combination of Hodel and Tanaka.
The Examiner finds that it is “well known in the art that in order to
have ‘high voltage between the source contact S and the drain contact D’,
the source S, the drain D and the bridge 134 must have the same dopant
type as that of the second doped regions 118.” (Final Act. 4). The Examiner
finds that in the present case of Hodel, a P-MOS transistor would have had
the source S, drain D, and the bridge 134 be the p-type, which is the same as
the second doped region 118 (Final Act. 4). The Examiner further finds that
Kunz discloses a transistor where the source, drain and doped bridge region
are doped with the same p-type dopant (Final Act. 5). The Examiner
concludes that it would have been obvious to form the power transistor of
4
Appeal 2017-002610
Application 12/618,546
Hodel having the source, drain and bridge regions doped the same as the
second doped region as taught by Kunz to reduce off-state leakage (Final
Act. 5).
The preponderance of the evidence favors the Examiner’s obviousness
conclusion. Although the Examiner’s reason for modifying Hodel with
Kunz is based upon reducing off-state leakage, the Examiner is not
proposing to modify Hodel to use Kunz’s composite transistor as argued by
Appellants. Rather, the Examiner relies on Kunz to support the Examiner’s
Official Notice that it is “well known in the art that in order to have ‘high
voltage between the source contact S and the drain contact D’, the source S,
the drain D and the bridge 134 must have the same dopant type as that of
the second doped regions 118.” (Final Act. 4). In other words, Kunz is used
to show that it is known to have the source, drain and bridge region doped as
P+ in a P-MOS transistor (Ans. 3). Appellants’ arguments about the
combination of Kunz with Hodel frustrating Hodel’s purpose or rendering
Hodel unsuitable for its intended use do not address and therefore have not
shown reversible error with the Examiner’s rejection based upon Official
Notice that P-MOS transistors have the drain, source and bridge regions
doped with P+-type dopants as further supported by Kunz.
On this record, we affirm the Examiner’s § 103 rejections of record.
DECISION
The Examiner’s decision is affirmed.
5
Appeal 2017-002610
Application 12/618,546
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
ORDER
AFFIRMED
6