Ex Parte Masumoto

Board of Patent Appeals and Interferences

Jan 26, 2007

10422290 (B.P.A.I. Jan. 26, 2007)

The opinion in support of the decision being entered today was not written
for publication and is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte MUTSUMI MASUMOTO
____________

Appeal 2006-3286
Application 10/422,290
Technology Center 1700
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Decided: January 27, 2007
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Before EDWARD C. KIMLIN, THOMAS A. WALTZ, and
CATHERINE Q. TIMM, Administrative Patent Judges.

WALTZ, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on an appeal from the Primary Examiner’s final
rejection of claims 1 through 12 and 16 through 19, which are the only
claims pending in this application. We have jurisdiction pursuant to 35
U.S.C. § 134.
According to Appellant, the invention is directed to a method of
thinning a semiconductor wafer, where the wafer has two flat surfaces and a
Appeal 2006-3286
Application 10/422,290

round periphery between the flat surfaces. The method comprises selecting
a generally circular support tape to place below the wafer, and thinning the
wafer by removing semiconductor material from the second wafer surface
until the intended thickness is achieved (Br. 2).1 The diameter of the tape is
selected to be greater than the diameter of the wafer at each side by an
amount about equal to the length of the rounding at the edge of the wafer
after thinning is accomplished (id.).
Appellant states that the claims should be considered as three groups
(Br. 5). However, Appellant does not discuss each group of claims under a
separate heading and only presents specific, substantive arguments regarding
claims 1, 11, and 16 (e.g., Br. 6; Answer 2). Accordingly, we limit our
consideration to claims 1, 11, and 16 to the extent these claims are separately
argued. Illustrative independent claim 1 is reproduced below:
1. A method of thinning a semiconductor wafer having first and
second flat surfaces of a first diameter and a rounded periphery between said
flat surfaces, comprising the steps of:

selecting a generally circular support tape for said wafer, said tape
having a second diameter;

selecting said second diameter to be greater than said first diameter by
an amount about equal to the length of said peripheral wafer rounding as
obtained in said wafer after said thinning step is completed;

placing said first flat wafer surface on said tape; and removing
semiconductor material from said second wafer surface until the intended
thickness is achieved.

1 We refer to and cite from the “Response to Non-Compliant Appeal Brief”
dated Apr. 19, 2006.
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Application 10/422,290

The Examiner has relied upon the following references as evidence of
obviousness:
Xin US 6,227,944 B1 May 08, 2001
Yamamoto US 6,767,426 B1 Jul. 27, 2004
ISSUES ON APPEAL
The claims on appeal stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Yamamoto in view of Xin (Answer 3).
Appellant contends that neither reference discloses the selection of a
support tape where the diameter of the tape is greater than the diameter of
the wafer by an amount about equal to the length of the peripheral wafer
rounding after thinning (Br. 6). Appellant also contends that the definition
of the diameter of the wafer in this application is different from the diameter
as disclosed by the applied references (Br. 7-9).
The Examiner contends that Yamamoto teaches that the diameter of a
support tape layer for a semiconductor wafer in a thinning process may be
greater than the diameter of the wafer surface while Xin teaches the
advantages of providing a rounded periphery for each wafer (Answer 3).
Accordingly, we determine that the issue in this appeal is whether the
combination of references disclose or suggest a support tape in a thinning
process with the same relative diameter as required by claim 1 on appeal,
based upon a rounded periphery between the surface edges of the wafer.
Based on the totality of the record, we AFFIRM this rejection on
appeal essentially for the reasons stated in the Answer, as well as those
reasons set forth below.
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Application 10/422,290

OPINION
The Examiner finds, and Appellant does not dispute, the following
facts:
(1) Yamamoto discloses a semiconductor wafer having first and
second flat surfaces of a first diameter (Answer 3);
(2) Yamamoto discloses a thinning process where semiconductor
material may be removed from the second wafer surface by
grinding or etching until the intended thickness is achieved (id.);
(3) Yamamoto teaches that a support tape having a second diameter
may be used, where the second diameter is greater than the first
diameter (id.);
(4) Yamamoto does not disclose that the periphery between the wafer
edges may be rounded (id.); and
(5) Xin teaches that the peripheral edge of each wafer may first be
rounded before further processing in order to reduce the risk of
wafer damage during this processing (id.).
It is well-established that before a conclusion of obviousness may be
made based on a combination of references, there must have been a reason,
suggestion, or motivation to lead an inventor to combine these references.
See Pro-Mold and Tool Co. v. Great Lakes Plastics, Inc., 75 F.3d 1568,
1573, 37 USPQ2d 1626, 1629 (Fed. Cir. 1996). “When relying on
numerous references or a modification of prior art, it is incumbent upon the
examiner to identify some suggestion to combine references or make the
modification. [Citation omitted].” In re Mayne, 104 F.3d 1339, 1342,
41 USPQ2d 1451, 1454 (Fed. Cir. 1999).
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Application 10/422,290

We determine that the Examiner has clearly identified a reason or
motivation to combine the references, namely the advantage of providing
peripheral rounding of wafer edges to avoid the risk of wafer damage during
subsequent processing (Answer 3). We note that Appellant does not dispute
this teaching of Xin but merely argues that no rounding is evident in Figure
3 of Xin (Br. 7). However, we note that a reference is not limited to its
examples but is available for all that it discloses or suggests to one of
ordinary skill in the art. See In re Widmer, 353 F.2d 752, 757, 147 USPQ
518, 523 (CCPA 1965). Additionally, we determine that Xin teaches that
such rounding is conventional in this art (col. 1, ll. 20-23), and rounding is
specifically taught for the Xin process, although not shown (col. 4, ll. 1-4).
Appellant’s arguments regarding the determination of diameters in the
references as opposed to the diameters recited in the claims on appeal are
also not persuasive. Yamamoto specifically teaches that the protective tape
is cut into the “approximately same shape as the wafer” but may be cut into
a shape having a diameter larger than the outer diameter of the wafer (col. 8,
ll. 9-12; see also col. 2, ll. 45-47). We determine that Xin discloses that one
surface of the wafer can be covered with a protective tape, where the tape
adheres to the front surface of the wafer but can be removed after the back
surface damaging (thinning) operation (col. 5, ll. 4-10). We further
determine that Xin teaches that the protective layer covering the front
surface functions to “protect(s) the front surface against damaging
engagement” with the belt of the pressure jetting machine (or other
apparatus used for thinning) (col. 5, ll. 40-42). We thus determine that it
would have been obvious to one of ordinary skill in this art to employ a tape
with a diameter that would accomplish the function desired for the tape
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layer, namely to protect and support one side of the wafer and any peripheral
edge that was not being thinned, i.e., protect the wafer up to the point of
thinning.
For the foregoing reasons and those reasons stated in the Answer, we
determine that the Examiner has established a prima facie case of
obviousness in view of the reference evidence. Based on the totality of the
record, including due consideration of Appellant’s arguments, we determine
that the preponderance of evidence weighs most heavily in favor of
obviousness within the meaning of § 103(a). Accordingly, the rejection of
claims 1-12 and 16-19 under § 103(a) over Yamamoto in view of Xin is
affirmed.
The decision of the Examiner 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)(2007).
AFFIRMED

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