Ex parte Melton et al.

Board of Patent Appeals and Interferences

Jun 19, 2001

08677755 (B.P.A.I. Jun. 19, 2001)

-1-
The opinion in support of the decision being entered
today was not written for publication and is not
binding precedent of the Board.
Paper No. 17
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________
Ex parte CYNTHIA MELTON and THERESA L. BAKER
________________
Appeal No. 1998-3053
Application 08/677,755
________________
ON BRIEF
________________
Before PAK, OWENS and LIEBERMAN, Administrative Patent Judges.
OWENS, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the examiner’s final rejection of
claims 13-18, which are all of the claims remaining in the
application.
THE INVENTION
The appellants’ claimed invention is directed toward a
method for attaching an integrated circuit component to a
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substrate by solder bump connections, wherein the solder has a
specified composition. Claim 13 is illustrative:
13. A method for attaching an integrated circuit
component to a substrate by solder bump interconnections, said
substrate comprising a plurality of first bond pads, said
integrated circuit component comprising a plurality of second
bond pads formed of solder-wettable metal, said method
comprising:
forming a solder bump onto each second bond pad, said
solder bump being formed of a lead-free solder alloy composed
predominantly of tin and optionally up to 1.5 weight percent
silver and containing between 2 and 8 weight percent copper,
superposing the integrated circuit component onto the
substrate to form an assembly such that each solder bump rests
against a corresponding first bond pad,
heating the assembly for a time and at a temperature
effective to melt said lead-free solder, whereupon each solder
bump forms molten solder that wets the corresponding first
bond pad, and
cooling to solidify the solder to form solder bump
interconnections bonding the first bond pads and the second
bond pads.
THE REFERENCES
Tulman 4,806,309 Feb. 21,
1989
Melton et al. (Melton ‘341) 5,154,341 Oct. 13,
1992
Melton et al. (Melton ‘453) 5,269,453 Dec. 14,
1993
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Application 08/677,755
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THE REJECTIONS
Claims 13-18 stand rejected as follows: under the
judicially created doctrine of obviousness-type double
patenting over
claim 1 of Melton ‘453 in view of Tulman, and under 35 U.S.C.
§ 103 as being unpatentable over Melton ‘341 in view of
Tulman.
OPINION
We reverse the aforementioned rejections.
Obviousness-type double patenting rejection
Claim 1 of Melton ‘453 recites that the assembly is
heated to a temperature greater than the melting temperature
of a solder composition formed of first and second metal
constituents, but less than the melting temperature of each of
these constituents, such that the first and second metals
cooperate to form an interfacial liquid phase that wets a
metal plate composed of the first metal and a metal bump
composed of the second metal.
Tulman discloses a solder composition which typically is
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Application 08/677,755
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95.5 wt% tin, 4 wt% copper and 0.5 wt% silver, and teaches
that this solder composition has an undesirably high melting
point of approximately 440EF (226.7EC) and is undesirably hard
(col. 1, lines 24-29).
The examiner argues that “it would have been obvious to
one of ordinary skill in the art to have formed the solder
bump interconnection according to Melton ‘453, using the
solder disclosed by Tulman by heating to a temperature between
225EC and 240EC due to the disclosed melting point and because
of the known benefit of raising the melting point of a solder
by the addition of copper {Paper #9, Preliminary Amendment
‘C’, page 5, line 22}” (final rejection, paper no. 13, page
3). The preliminary amendment referred to by the examiner
states: “It is well known in the art that copper raises the
melting point of solders.” The examiner states that “the
examiner takes official notice that it would be obvious to one
of ordinary skill in the art to heat solder bumps above their
melting temperature to promote the connection of components”
(final rejection, page 5).
As discussed above, however, claim 1 of Melton ‘453 does
not recite melting the at least one solder bump but, rather,
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recites heating to a lower temperature than the melting
temperatures of the first and second metal constituents such
that an interfacial liquid phase is formed which wets the
metal plate and the solder bump. Melting the solder bump
clearly would not have produced the required interfacial
liquid phase which wets the solder bump. Moreover, the
examiner has not explained why, if Tulman’s solder were used
in the method of claim 1 of Melton ‘453, the claim requirement
would be met that the second metal of which the solder is
composed forms, with the first metal of which the metal plate
is composed, a solder composition having a melting temperature
lower than that of the first and second metals.
The examiner, therefore, has not carried the burden of
establishing a prima facie case of obviousness over claim 1 of
Melton ‘453 in view of Tulman. Accordingly, we reverse the
rejection over these references.
Rejection under 35 U.S.C. § 103
Melton ‘341 discloses forming a high-melting spacer
solder bump (28) surrounded by lower-melting solder (36), and
heating to a temperature below the melting temperature of the
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spacer solder bump such that the lower-melting solder
liquefies and wets the spacer solder bump (col. 4, lines 21-24
and 50-56; col. 4, line 66 - col. 5, line 5; col. 5, lines 38-
43; col. 6, lines 27-35).
The examiner argues that “it would have been obvious to
one of ordinary skill in the art to have formed the solder
bump interconnection according to Melton ‘341, using the
solder disclosed by Tulman because of the known benefit of
raising the melting point of a solder by the addition of
copper {Paper #9, Preliminary Amendment ‘C’, page 5, line 22}”
(final rejection, page 4).
Even if Tulman’s solder were substituted for the
Melton ‘341 spacer bump solder in order to obtain a higher
melting temperature resulting from the copper component, the
result would not be the appellants’ claimed invention. The
reason is that the Melton ‘341 spacer solder bump is not
melted, whereas the appellants’ claims require melting the
solder bump. Consequently, we reverse the rejection over
Melton ‘341 in view of Tulman.
DECISION
The rejection of claims 13-18 under the judicially
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created doctrine of obviousness-type double patenting over
claim 1 of Melton ‘453 in view of Tulman, and under 35 U.S.C.
§ 103 over Melton ‘341 in view of Tulman, are reversed.
REVERSED
CHUNG K. PAK )
Administrative Patent Judge )
)
)
)
TERRY J. OWENS ) BOARD OF
PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
PAUL LIEBERMAN )
Administrative Patent Judge )
TJO/ki
Motorola, Inc.
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