Ex Parte Ho et al

Patent Trial and Appeal Board

May 18, 2018

14552086 (P.T.A.B. May. 18, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
14/552,086 11/24/2014
65913 7590 05/22/2018
Intellectual Property and Licensing
NXPB.V.
411 East Plumeria Drive, MS41
SAN JOSE, CA 95134
FIRST NAMED INVENTOR
Chung Hsiung Ho
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
81639293US01 7615
EXAMINER
CAMPBELL, SHAUN M
ART UNIT PAPER NUMBER
2829
NOTIFICATION DATE DELIVERY MODE
05/22/2018 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):
ip.department.us@nxp.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte CHUNG HSIUNG HO, BENSONIL CHAN, and
CHIEN KUO
Appeal2017-007355
Application 14/552,086
Technology Center 2800
Before DONNA M. PRAISS, CHRISTOPHER L. OGDEN, and
DEBRA L. DENNETT, Administrative Patent Judges.
PRAISS, Administrative Patent Judge.
DECISION ON APPEAL 1
STATEMENT OF THE CASE
This is an appeal under 35 U.S.C. § 134 from the final rejection of
claims 1---6. Final Act. 3-7; App. Br. 3. We have jurisdiction under
35 U.S.C. § 6(b ).
We AFFIRM.
The subject matter of this appeal relates to a process for sawing a low
dielectric constant wafer substrate having active devices so as to minimize
1 In explaining our decision, we make reference to the Specification filed
November 24, 2014 ("Spec."), the Final Office Action mailed March 16,
2016 ("Final Act."), the Appeal Brief filed October 24, 2016, as corrected
November 16, 2016 ("App. Br."), the Examiner's Answer mailed January 5,
2017 ("Ans."), and the Reply Brief filed March 6, 2017 ("Reply Br.").
Appeal2017-007355
Application 14/552,086
side wall damage along active device edges. Spec. ,r 1. According to the
Specification, by sawing a first cut of Zl on the back-side surface of the
wafer substrate, the maximum shift is reduced to which the active devices on
the front-side of the wafer would be exposed and the smaller kerf of the
second cut of Z2, after laser grooving between the active devices on the
wafer front-side to remove metallization, lessens the probability of
damaging active areas of the die with its reduced shift. Id. ,r,r 29, 45. Claim
1 is illustrative:
1. A method for sawing a wafer substrate, the wafer
substrate having a front-side surface containing active devices
separated by saw lanes and a back-side surface having
undergone back grinding, the saw lanes having process control
monitor (PCM) devices present therein, the method comprising:
mounting the wafer substrate onto a carrier tape on the
front-side surface;
with a blade of a first kerf, W z1, sawing the back-side
surface in tracks corresponding to the saw lanes, to a first
depth;
applying carrier tape to the back-side surface of the wafer
substrate;
removing the carrier tape from the front-side surface;
laser grooving (LG) the saw lanes, to an LG depth, on the
front-side surface of the wafer substrate until PCM devices are
substantially removed, the LG having a preset beam diameter,
WLa; and
with a blade of a second kerf, W z2, the second kerf less
than the first kerf, sawing the front-side surface of the wafer
substrate about the center of the saw lanes to enable the
separation of the active devices from one another;
wherein WLa>Wz1>WZ2.
App. Br. 14 (Claims Appendix).
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Application 14/552,086
Appellant's Figures 2A through 2C below illustrate Appellant's wafer
dicing process. Spec. ,r 13.
----------·'
.+,
I
1!
\ ... ! l........... . ..... '
: \ · ...... •· ......... '
\\ 30
\
250
Fl(r 2.A HC. 2B FlG. 2.C
Figure 2A above shows blade 5 having width Z 1, Figure 2B above shows
laser beam 10 having diameter 25 (width LG) which is close to that of saw
lane 20, and Figure 2C above shows blade 15 having width Z2. Spec. ,r,r 5,
30.
The Examiner maintains, 2 and Appellant3 appeals, the rejection of
claims 1-6 under 35 U.S.C. § 103 as unpatentable over Qiu4 in view of
Park. 5 Ans. 2; App. Br. 3. Appellant argues the subject matter of claims
2 The rejection of claims 5, 6, and 10 under 35 U.S.C. § 112(b) as indefinite
has been withdrawn. Ans. 2.
3 Appellant is the Applicant, NXP B.V., identified in the Brief as the real
party in interest. App. Br. 3.
4 Qiu et al., US 2014/0024199 Al, pub. Jan. 23, 2014 ("Qiu").
5 Park, US 2006/0169680 Al, pub. Aug. 3, 2006.
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Application 14/552,086
1---6 as a group. App. Br. 4. In accordance with 37 C.F.R. § 4I.37(c)(l)(iv),
claims 2-6 will stand or fall together with claim 1.
OPINION
The dispositive issues for this appeal are (1) whether the Examiner
erred in modifying Qiu's teaching that active devices are separated from
each other with one saw cut at the back-side of a wafer and a laser scribe on
the front-side of the wafer with Park's teaching to separate active devices
from each other with a saw cut on the front-side of a wafer, (2) whether the
Examiner erred in finding that Qiu teaches that the grooving on the back-
side of a wafer should be larger than the final cutting width, and (3) whether
the Examiner erred in finding that Park teaches a laser grooved trench
having a width greater than the width of a mechanical cutter.
After review of the arguments and evidence presented by both
Appellant and the Examiner, we affirm the stated rejection.
It is the Examiner's position that Qiu in view of Park suggests the
subject matter of claims 1---6 for the reasons stated on pages 3-7 of the Final
Office Action.
In the Appeal Brief, Appellant argues that the Examiner's rejection is
in error because no reasoning was articulated for sawing both the back-side
surface and the front-side surface of a wafer with blades to separate active
devices. App. Br. 7. Appellant contends that neither Qiu nor Park suggest
separating active devices with saw cuts on both sides because Qiu teaches
separation with two saw cuts at the front-side of a wafer and Park teaches
separation with a saw cut only on the front-side of a wafer. Id. at 8.
Regarding the Examiner's reasoning that the combination of prior art
teaches the relationship of WLa>Wz1>WZ2, Appellant contends that the
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Application 14/552,086
reasoning does not articulate why a skilled artisan would saw both the back-
side surface and the front-side surface of a wafer with blades to separate
active devices. Id. at 8-10. In addition, Appellant contends that Qiu teaches
away from WLa>Wz1 because Qiu's laser beam produces regions below the
front surface over a width less than and included within the width of the
grooves. Id. at 11 (citing Qiu ,r 27). Appellant also contends that Park is
silent as to the relative widths of the laser beam and the mechanical cutter,
therefore, Qiu in view of Park does not teach or suggest the relative kerfs of
the saw blades. Id. at 12 (citing Park Figs. 9-12).
Appellant argues that unexpected results were achieved from the
double-sided sawing, and cites paragraphs 39-46 and Figures 5A and 8 as
evidence of such unexpected results, pointing out that paragraph 45 states
that the probability of sawing damaging active areas of the integrated circuit
device die was lessened. Id. at 10-11.
The Examiner responds that a skilled artisan would have substituted
Qiu's single step process of laser cutting the front-side surface of the wafer
with Park's two-step cutting process of laser cutting and sawing with a blade
to improve the devices by allowing the incorporating of testing elements
onto the wafer without wasting valuable chip space. Ans. 3--4 ( citing Park
Fig. 9, testing elements 910, and Fig. 10, laser cutting 1000). The Examiner
finds that Park's laser cutting process requires a larger cutting width for the
purpose of completely removing the testing elements followed by cutting
with a blade having a smaller width similar to the final laser cutting step of
Qiu. Id. at 5. The Examiner additionally finds that Park's disclosure that
multiple passes with the laser beam may be used to form the laser grooved
trench also suggests forming the trench with a single pass, particularly in the
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Application 14/552,086
interest of shortening manufacturing time; thus, a less fine cut would be
beneficial. Id. at 6-7 (citing Park ,r 52).
Regarding Qiu's cutting widths, the Examiner finds that Qiu uses a
laser beam cutter 702 with a width smaller than the width of the cutting
operation on the backside of the wafer such that wasted cutting space is on
the back side, therefore, Qiu teaches the final cutting operation should have
a width less than the width of the cutting operation on the back-side surface
(the second kerfWZ2 by Park's blade). Id. at 5, 7 (citing Qiu ,r,r 17, 27).
Regarding Appellant's showing of unexpected results, the Examiner
finds that it would have been expected to be easier to cut through a thinner
rather than a thicker region because there is less material to cut through. Id.
at 4. The Examiner also finds that a lower probability of damage to the
opposite side of the cutter in a cutting process would have been expected.
Id.
In the Reply Brief, Appellant argues that there is no reason to
substitute Park's two-step process in the process of Qiu because Qiu does
not teach or suggest the need to remove test pattern circuitry. Reply Br. 4
( citing Qiu ,r 3 regarding the desirability to allow for more area on the wafer
to be used for forming circuitry). According to Appellant, a skilled artisan
would be motivated to use the two-step process of Park itself rather than that
of Qiu if it was necessary to remove a test pattern in the saw streets. Id. at 5.
Because Qiu teaches using a laser beam to scribe the front-side of the wafer,
Appellant asserts that Qiu does not teach or suggest a relationship between
the kerfs of two saw blades of W z1> W z2, but only the relative widths of a
saw blade and a laser scribe. Id. at 6, 8. Regarding the relative widths of the
mechanical cutter and the laser beam of Park, Appellant asserts that the
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Application 14/552,086
diameter of the laser beam appears smaller than the width of the saw blade
in Park's Figures 10 and 11, e.g., WZ2>WLa, and that the Examiner's
position otherwise is not supported by the record. Id. at 7.
We review the appealed rejection for error based upon the issues
identified by Appellant and in light of the arguments and evidence produced
thereon. Cf Ex parte Frye, 94 USPQ2d 1072, 107 5 (BP AI 2010)
(precedential) (cited with approval in In re Jung, 637 F.3d 1356, 1365 (Fed.
Cir. 2011) ("it has long been the Board's practice to require an applicant to
identify the alleged error in the examiner's rejections"). We find
Appellant's arguments unpersuasive of reversible error by the Examiner for
the following reasons.
Appellant does not dispute the Examiner's findings regarding the
relative widths taught by Qiu between the final cut and the back-side cut.
Instead, Appellant points out that Qiu's final cut is a scribe and not a blade.
Appellant's argument is not persuasive because it argues the references
individually rather than the combination of art on which the rejection is
based. See In re Keller, 642 F.2d 413,426 (CCPA 1981); In re Merck &
Co., Inc., 800 F.2d 1091, 1097 (Fed. Cir. 1986). It is also not persuasive
because in a determination of obviousness, a reference may be relied upon
for all that it would have reasonably suggested to one having ordinary skill
in the art. Merck & Co. v. Biocraft Labs., 874 F.2d 804, 807 (Fed. Cir.
1989). The Examiner's finding that Qiu teaches the final cut ("singulation")
has a substantially reduced width is supported by the record. Qiu ,r,r 17, 27.
Qiu quantifies the width (SI) of the groove (604) on the back-side as
approximately 40 µm and the width (S2) of the scribing on the front-side as
less than 10 µm. Id. ,r,r 26, 27.
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Application 14/552,086
Appellant's argument (Reply Br. 4--5) that a skilled artisan would not
be motivated to substitute Park's two-step process on the front-side of the
wafer for Qiu's single cutting operation because Park's method can be used
alone for removing test circuitry and Qiu does not teach the need to remove
test pattern circuitry is not persuasive because the removal of test circuitry is
an articulated reason provided by the Examiner for modifying the method of
Qiu. The Examiner's reasoning is supported by the record, namely Park.
Simply because Park teaches the removal of test circuitry with its two-step
process and could be used for this purpose absent combination with Qiu is
insufficient to rebut the articulated benefit of the step in Qiu's process.
Regarding the relative widths of Park's laser 1000 and blade 1100, the
Examiner's rejection relies upon the teachings of Qiu for the relative sizes of
both ( 1) the kerf of the saw blade on the back-side of the wafer having a
larger width than cutting on the front-side, based on Qiu's teaching
regarding wasted space being located on the back-side, as well as (2) the
final cut having the smallest width. The Examiner relies on Park for
teaching the width of the laser grooving being such that test circuity may be
removed. Ans. 3 ( citing Park, Figs. 9, 10). Appellant does not dispute that
Park uses laser grooving for the purpose of removing testing elements and
the Examiner's findings are supported by the record. Park, Fig. 9 ( testing
elements 910) and Fig. 10 (laser cutting 1000 removes testing elements 910).
The Examiner further determines that it would have been within the
level of skill of one of ordinary skill in the art at the time of the invention to
choose the desired width of the laser beam for a particular laser grooving
operation to form the laser groove with a single pass, thus drastically
shortening the manufacturing time. Ans. 6-7. In the Reply Brief, Appellant
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Application 14/552,086
does not dispute that it would have been within the level of skill of one
having ordinary skill in the art to select a desired width of the laser beam for
a particular grooving operation that removes testing circuity in a single pass,
nor does Appellant argue that a grooving operation for the purpose of
removing testing circuitry would not have a larger width than both the
singulation width and the back-side groove width disclosed in Qui.
Therefore, Appellant's arguments regarding the relative widths required by
claim 1 are not persuasive because they argue the references individually
rather than the combination of the teachings from each reference as applied
in the rejection.
Regarding Appellant's evidence of unexpected results, a party
asserting unexpected results as evidence of nonobviousness has the burden
of proving that the results are unexpected. In re Geisler, 116 F.3d 1465,
1469--70 (Fed. Cir. 1997). "[I]t is not enough to show that results are
obtained which differ from those obtained in the prior art: that difference
must be shown to be an unexpected difference." In re Klosak, 455 F.2d
1077, 1080 (CCPA 1972). Moreover, "when an inventor tries to distinguish
his claims from the prior art by introducing evidence of unexpected
'synergistic' properties, the evidence should at least demonstrate 'an effect
greater than the sum of the several effects taken separately."' Merck & Co.,
874 F.2d at 808 (citing Sakraida v. Ag Pro, Inc., 425 U.S. 273,282 (1976)).
Appellant's evidence shows no more than "the smaller kerf of the second cut
of Z2, after the laser grooving, with its reduced shift, lessens the probability
of the sawing/singulation process damaging active areas of the integrated
circuit device die" (Spec. ,r 45). Such evidence is insufficient to rebut the
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Application 14/552,086
Examiner's obviousness determination, particularly in view of Qiu's
teaching that the last singulation cut has the smallest width.
For the foregoing reasons, we affirm the Examiner's rejection of
claims 1-6 under 35 U.S.C. § 103.
CONCLUSION
The Examiner's rejection of claims 1-6 under 35 U.S.C. § 103 is
affirmed.
No time period for taking any subsequent action in connection with
this appeal maybe extended under 37 C.F.R. § 1.136(a)(l)(v).
AFFIRMED
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