Ex Parte Pendse et al

Patent Trial and Appeal Board

Jul 1, 2014

12688124 (P.T.A.B. Jul. 1, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte RAJENDRA D. PENDSE and
STEPHEN A. MURPHY
____________

Appeal 2012-005474
Application 12/688,124
Technology Center 2800
____________

Before ANTON W. FETTING, MICHAEL C. ASTORINO, and
JAMES A. WORTH, Administrative Patent Judges.

WORTH, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s final
rejection of claims 26–32, 34, 35, and 37–52 which constitute all the claims
pending in this application. 1, 2 We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.

1 We refer to the Appeal Brief (filed Aug. 9, 2011, hereinafter “Br.”) and the
Answer (mailed Nov. 16, 2011, hereinafter “Ans.”) for the respective
positions of Appellants and the Examiner.
2 The real party in interest identified by Appellants is STATS CHIPPAC,
LTD. of Singapore. Br. 1.
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Introduction
Appellants’ disclosure relates to a method of packaging a
semiconductor device, and to semiconductor devices themselves,
characterized by a flip chip interconnect structure having a void-free fine
pitch. Spec. 1.
Claims 26, 31, 37, and 45 are the independent claims on appeal.
Claim 26 is illustrative and reads as follows:
26. A method of making a semiconductor device,
comprising:
providing a semiconductor die having a contact pad;
forming a rounded bump on the contact pad;
providing a substrate having a trace line;
forming a solder resist layer over the substrate;
forming a star shaped solder resist opening in the solder
resist layer and over a portion of the trace line, the star shaped
solder resist opening having rounded tips that extend beyond a
width of the rounded bump;
placing the rounded bump in proximity to the portion of
the trace line;
reflowing the rounded bump to metallurgically connect
the reflowed rounded bump to a top and side surfaces of the
portion of the trace line, wherein the reflowed rounded bump is
within and contacts less than an entire perimeter of the solder
resist opening which creates vents in areas where the reflowed
rounded bump is discontinuous with the solder resist opening;
and
depositing underfill material under the semiconductor
die, the underfill material penetrating through the vents to fill
an area within the solder resist opening and under the reflowed
rounded bump to be void-free.

Br., Claims App.

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Prior Art Relied Upon
Tsukada US 6,228,466 B1 May 8, 2001
Wu US 2002/0071935 A1 June 13, 2002
Tsai US 6,787,918 B1 Sept. 7, 2004
Liu US 2008/0042278 A1 Feb. 21, 2008
Rejections On Appeal
The Examiner maintains, and the Appellants appeal, the following
rejections:
1) claims 26–30 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Liu, Tsai, and Wu;
2) claims 31, 32, 34, and 35 stand rejected under 35 U.S.C. § 103(a)
as unpatentable over Liu, Tsukada, and Tsai; and
3) claims 37–52 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Liu and Tsai.
ANALYSIS
Independent claim 26 and its dependent claims
The Examiner finds that Liu substantially describes the subject matter
of claim 26. However, Liu does not disclose certain requirements of claim
26, including the use of the semiconductor die as the support, the star-shaped
opening, and the underfill that penetrates through the vents to be void-free.
Ans. 5–6. The Examiner concludes that it would have been obvious to
modify Liu in view of the disclosure of Tsai to use the semiconductor die as
the support and to use underfill material penetrating through vents to be
void-free. Id. at 6 (citing Tsai, Figure 5 and col. 5, ll. 6–10). The Examiner
explains that this modification would increase the security of the substrate
connection and the ability of the package to sustain thermal stress. Id. The
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Examiner concludes that it would have been obvious to further modify Liu
in view of Wu to have a star-shaped opening to vent the reflowed rounded
ball material and to allow underfill to create a better bond in the package.
Id. (citing Wu, Fig. 7).
Appellants argue that none of the prior art references teach “forming a
star shaped solder resist opening . . . having rounded tips that extend beyond
a width of the rounded bump.” Br. 19. However, the Examiner correctly
concludes that “star-shaped” has no special definition and finds that Figure 7
of Wu demonstrates star shaped-grooves. Ans. 6, 13. Appellants argue that
the ditch-like grooves (321) in Wu do not extend beyond a width of the
rounded bump. Br. at 19–20. We do not find this argument persuasive
because the Examiner relies on Liu for this limitation. Ans. 14.
Appellants next argue that none of the prior art references teach
“reflowing the rounded bump to metallurgically connect the reflowed
rounded bump to a top and side surfaces of the portion of the trace line.” Br.
20. Specifically, Appellants argue that Liu teaches away from such
connection because Liu describes the solder ball mounted to the ball pad and
not to the trace line. Id. at 20–21. We are not persuaded by Appellants’
argument. The Examiner correctly determines that a person of ordinary skill
in the art would know that the trace line may be integrally formed with the
ball pad. Ans. 14–15. Indeed, under the broadest reasonable interpretation
of the term “trace line,” the trace line includes the rounded pad. This is
borne out by the Specification, which describes that “[t]race line 50 can have
a rounded pad 52.” See Spec. 8 ¶ 16 and Fig. 5a-b. Further, claim 28 recites
“[t]he method of claim 26, wherein the trace line includes a rounded contact
pad,” which demonstrates that the “trace line” of claim 26 may include a
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contact pad. Therefore, a metallurgic connection between the solder bump
and the rounded pad constitutes a metallurgic connection between the solder
bump and the trace line below.
Appellants argue that none of the prior art references teach a
“reflowed rounded bump is within and contacts less than an entire perimeter
of the solder resist opening which creates vents in areas where the reflowed
rounded bump is discontinuous with the solder resist opening.” Br. 21.
Appellants argue that the size of the opening in Liu is described with respect
to the ball pad rather than the bump, i.e., Liu shows that the opening is larger
than the ball pad 202 rather than the bump itself, and that Liu does not show
that the rounded bump of Liu contacts less than an entire perimeter. Br. 22.
The Examiner submits that, “the combination [of Liu and Tsai] is sufficient
to meet the limitations of the claimed invention.” Id. The Examiner finds
that both Liu and Tsai teach solder resist openings formed larger than the
rounded bump. Id. Indeed, a bump in a larger opening is within the
broadest reasonable interpretation of “contacts less than an entire perimeter”
and creates vents “in areas where the . . . bump is discontinuous with the
solder resist opening.” Appellants further argue that the Examiner’s use of
the Wu reference undermines the use of vents in Liu because the grooves in
Wu are fully filled by the reflow process. Br. 22–23. This argument is not
persuasive because the Examiner cites Wu solely for the shape of the
opening. Ans. 15.
Appellants next argue that none of the prior art references teach
“depositing underfill material . . . penetrating through the vents to fill an area
within the solder resist opening and under the reflowed rounded bump to be
void-free.” Br. 23. Appellants assert that the SMD (Solder Mask Define)
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perimeter of Tsai avoids underfill. Br. 24. Appellants continue that the
NSMD (Non Solder Mask Define) center of Tsai lacks contact between the
bump and the solder resist opening, and therefore does not suggest using
underfill with the solder mask opening of Liu, which describes a ball pad
contacting less than an entire perimeter of the opening. Br. 25. However,
we agree with the Examiner that the claimed invention employs underfill to
penetrate otherwise-obscured areas in the same manner as Tsai and for the
same reason, i.e., to fill an area to be void free. See Ans. 16.
We therefore sustain the Examiner’s rejection of claim 26 under 35
U.S.C. § 103(a). Because Appellants only argue the Examiner’s rejections
of claims 27–30 on the basis of arguments relating to independent claim 26,
we also sustain the Examiner’s rejections of claims 27–30 under 35 U.S.C.
§ 103(a).
Claims 31, 32, 34, 35, and 37–52
Although we understand that there are different groups of references
and consequently different conclusions for the Examiner’s rejection of
claims 31, 32, 34, 35, and 37–52, Appellants’ arguments (Br. 31–39) with
respect to these claims are so similar to those for claim 26 that we find them
unpersuasive for similar reasons, as discussed above.
We therefore sustain the Examiner’s rejection of claims 31, 32, 34,
35, and 37–52 under 35 U.S.C. § 103(a).

DECISION
The decision of the Examiner to reject claims 26–32, 34, 35 and 37–
52 is affirmed.
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No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv).

AFFIRMED

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