Ex Parte Lin et al

Patent Trial and Appeal Board

Nov 15, 2013

11505141 (P.T.A.B. Nov. 15, 2013)

UNITED STATES PATENT AND TRADEMARKOFFICE
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.
11/505,141 08/16/2006 Wen Chin Lin N1085-461/TSMC2003-875DIV 4562
8933 7590 11/15/2013
DUANE MORRIS LLP - Philadelphia
IP DEPARTMENT
30 SOUTH 17TH STREET
PHILADELPHIA, PA 19103-4196
EXAMINER
LULIS, MICHAEL P
ART UNIT PAPER NUMBER
2824
MAIL DATE DELIVERY MODE
11/15/2013 PAPER
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.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
________________

Ex parte WEN CHIN LIN, DENNY TANG,
LI-SHYUE LAI, and CHAO-HSIUNG WANG
________________

Appeal 2011-007183
Application 11/505,141
Technology Center 2800
________________

Before TERRY J. OWENS, PETER F. KRATZ, and GEORGE C. BEST,
Administrative Patent Judges.

OWENS, Administrative Patent Judge.

DECISION ON APPEAL

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Application 11/505,141

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STATEMENT OF THE CASE
The Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
rejection of claims 1-9, 11-16, 18, and 19. We have jurisdiction under
35 U.S.C. § 6(b).
The Invention
The Appellants claim a method for forming a write line in a magnetic
random access memory device. Claim 1 is illustrative:
1. A method for forming a write line in a magnetic random access
memory device, the method comprising:
forming a trench in a substrate material;
filling the trench with a conductive filler material layer;
forming a conducting buffer layer over the conductive filler material
and substrate, wherein the conducting buffer layer is in contact with the
conductive filler material layer; and
forming a magnetic tunnel junction (MTJ) device in contact with the
buffer layer,
wherein the MTJ device has a width that is twice a width of the
trench, and the MTJ device is centered over the trench.

The References
Deak (Deak ’486) US 2003/0207486 A1 Nov. 6, 2003
Low US 2003/0211726 A1 Nov. 13, 2003
Deak (Deak ’068) US 2003/0235068 A1 Dec. 25, 2003
Tuttle US 2004/0042261 A1 Mar. 4, 2004
The Rejections
The claims stand rejected under 35 U.S.C. § 103 as follows: claims 1,
2, 16, and 18 over Tuttle in view of Deak ’068, claims 3-5, 7, 9, 11, 12,
and 14 over Tuttle in view of Deak ’068 and Low, claims 6, 8, 13, and 15
over Tuttle in view of Deak ’068, Low and Deak ’486 and claim 19 over
Tuttle in view of Deak ’068 and Deak ’486.
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Application 11/505,141

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OPINION
We affirm the rejections.
The Appellants rely upon the same arguments with respect to all of
the claims (Br. 4-12). We therefore limit our discussion to one claim, i.e.,
claim 1. Claims 2-9, 11-16, 18, and 19 stand or fall with that claim. See
37 C.F.R. § 41.37(c)(1)(vii) (2007).
Tuttle forms a write line (802) in a magnetic random access memory
device by forming a trench (300) in an insulating material substrate (202)
(Fig. 3; ¶¶ 0034, 0040), filling the trench (300) with a conductive filler
material (700, Fig. 7; 802, Fig. 8; ¶ 0043), forming a conducting buffer layer
(etch stop layer 902 which can be conductive) over the conductive filler
material (802) and substrate (202) (¶¶ 0046-47), wherein the conducting
buffer layer (902) is in contact with the conductive filler material (802)
(Fig. 9), and forming a magnetic tunnel junction (MTJ) device (1002) in
contact with the buffer layer (902) (Fig. 10E), wherein the MTJ
device (1002) is relatively well aligned, i.e., centered, with respect to the
trench (800/802) (Fig. 10E; ¶ 0052).1 Tuttle illustrates the MTJ
device (1002) as having a width greater than the width of the
trench (800/802) (Fig. 10E) but Tuttle does not discuss any relationship
between those widths.
Deak ’068 discloses that “[t]he field generated by a flat conductor is
proportional to the current density in the conductor, [thus] a narrower
conductor produces a larger field for a given current. In order to improve

1 An MTJ device (1102) which is relatively poorly aligned with the
trench (800/802) is shown in Fig. 11E (¶ 0052).
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Application 11/505,141

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the write efficiency of an MRAM [magnetic random access memory] bit, at
least one, and preferably both of the first and second conductors 14, 16
should have a width which is between one-half and two-thirds the
corresponding width of the sense layer [which corresponds to Tuttle’s
second ferromagnetic layer (908) (Deak ’068, ¶¶ 0002, 0021; Tuttle,
¶ 0045)]” (¶ 0022).
Thus, Deak ’068 would have led one of ordinary skill in the art,
through no more than ordinary creativity, to make the width of Tuttle’s write
line (802) as narrow as half the width of the MTJ device (1002) to produce a
larger field for a given current and thereby improve the MRAM’s write
efficiency. See KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007) (in
making an obviousness determination one “can take account of the
inferences and creative steps that a person of ordinary skill in the art would
employ”).
The Appellants argue (Br. 7) that the following disclosures by
Deak ’068 indicate that to obtain a desired result it is necessary for a trench
to be both narrowed and offset relative to the MTJ device:
When a memory cell is written, magnetization of the sense
layer starts to reverse (nucleate) at the edge of the sense layer.
With at least one of the row and column lines, being narrower
than the associated cell width and offset, the magnetic direction
of the sense layer of the cell can be reversed at a lower current
than if the column and row lines are the same size or wider than
the cell and are centered with respect to the cell. [¶ 0009]
. . .
The narrowing and positioning of the conductors maximizes the
flux delivered to the edge of the sense layer 18. [¶ 0023]

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Those disclosures do not indicate that the offsetting is necessary to
obtain the benefit provided by the narrowing but, rather, indicate that in
addition to the benefit provided by narrowing at least one of the row and
column lines, i.e., producing a larger field for a given current and thereby
improving the write efficiency the MRAM (¶ 0022), offsetting at least one
of the row and column lines such that its edge extends beyond the edge of
the sense layer (18) (¶¶ 0023-24; Figs.3, 4) provides the benefit of increased
magnetic flux.
The Appellants rely upon Deak ’068’s paragraph 0008 as showing
that the narrowing and offsetting are inextricably linked to each other (Br. 6-
7).
Deak ’068’s paragraph 0007 discloses that wide row and column lines
take up too much space, and paragraph 0008 discloses that narrowing the
row and column lines requires larger transistors. Those disclosures do not
indicate that offsetting the row and column lines is necessary to obtain the
benefit of narrowing them.
The Appellants argue that Deak ’068’s disclosure that “only one of
the conductors 16, 14 need extend over the corresponding edge of the sense
layer 18” (¶ 0026) does not suggest that the other conductor is centered
(Reply Br. 3-4).
Although Deak ’068 does not disclose that the other conductor is
centered, Deak ’068’s disclosure that only one of the conductors needs to be
offset (¶ 0026) would have indicated to one of ordinary skill in the art that
even if one of Tuttle’s conductors were offset according to Deak ’068’s
disclosure, the other conductor, narrowed according to Deak ’068’s
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disclosure (¶ 0022), could be centered, thereby meeting the Appellants’
claim requirement of an MTJ device having a width that is twice the width
of a trench.
For the above reasons we are not persuaded of reversible error in the
rejections.
DECISION/ORDER
The rejections under 35 U.S.C. § 103 of claims 1, 2, 16, and 18 over
Tuttle in view of Deak ’068, claims 3-5, 7, 9, 11, 12, and 14 over Tuttle in
view of Deak ’068 and Low, claims 6, 8, 13, and 15 over Tuttle in view of
Deak ’068, Low and Deak ’486 and claim 19 over Tuttle in view of
Deak ’068 and Deak ’486 are affirmed.
It is ordered that the Examiner’s decision 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).
AFFIRMED

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