Ex Parte Sett et al

Board of Patent Appeals and Interferences

Mar 23, 2007

10831012 (B.P.A.I. Mar. 23, 2007)

T
written for publication and is not inding precedent of the Board.

UNITED STATES P EMARK OFFICE
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BEFORE T APPEALS
AND INTERFERENCES
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Ex parte SUBHAM S Y CUNNINGHAM
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Technology Center 2800
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Decided: March 23, 2007
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S, and
HOMAS A. WALTZ, Administrative Patent Judges.
Administrative Patent Judge.

rejection of claims 1, 4, 5, 7, 9, and
11-21. Claim
ding capability to reduce operating temperature, comprising the
eps of :
electric
layers and a first conductive layer having a first array of electrical
he opinion in support of the decision being entered today was not
b
ATENT AND TRAD
HE BOARD OF PATENT

ETT and SHAWN JA

Appeal 2007-1055
Application 10/831,012

Before EDWARD C. KIMLIN, BRADLEY R. GARRI
T

KIMLIN,
DECISION ON APPEAL
This is an appeal from the final
1 is illustrative:
1. A method for fabricating a micro-scale device having internal
heat sprea
st

forming a heterostructure on a substrate comprising one or more di
Appeal 2007-1055
Application 10/831,012

2
transmission lines separated from the substrate by at least one of the
dielectric layers such that the first array is electrically isolated from the
substrate;

embedding a thermally conductive element in the one or more dielectric
layers at a location of the heterostructure where a heat transfer path can be
established in response to a thermal gradient generally directed from the first
array to the thermally conductive layer,

wherein adjacent transmission lines of the first array are separated from each
other by a distance ranging from approximately 25 to approximately 250
microns, and wherein the thermally conductive element has an out-of-plane
thickness ranging from approximately 0.1 to approximately 1 microns.
The Examiner relies upon the following references as evidence of
obviousness:
Fathy US 6,154,176 Nov. 28, 2000
Gotro US 2002/0162685 A1 Nov. 7, 2002
Swanson US 6,580,170 B2 Jun. 17, 2003
Appellants’ claimed invention is directed to a method for fabricating a
micro-scale device having internal heat spreading capability. The method
entails separating a first array of electrical transmission lines from a
substrate with a dielectric layer and embedding a thermally conductive
element in one of the dielectric layers. Adjacent transmission lines of the
array are separated from each other by a distance ranging from about 25 to
about 250 microns, and the thickness of the thermally conductive element is
approximately 0.1 to approximately 1 micron.
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Application 10/831,012

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Appealed claims 1, 4, 5, 7, 9, and 11-21 stand rejected under
35 U.S.C. § 103(a) as being unpatentable over Fathy in view of Gotro. The
appealed claims also stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Swanson in view of Gotro.
We have thoroughly reviewed the respective positions advanced by
Appellants and the Examiner. As a result, we concur with the Examiner that
the claimed subject matter would have been obvious to one of ordinary skill
in the art within the meaning of § 103 in view of the collective teachings of
Fathy and Gotro. Accordingly, we will sustain the Examiner’s rejection of
the appealed claims over the combination of Fathy and Gotro. We will not,
however, sustain the Examiner’s rejection over the combined teachings of
Swanson and Gotro.
We consider first the Examiner’s rejection of the appealed claims over
Fathy in view of Gotro. We agree with the Examiner that figure 5 of Fathy
depicts an array of electrical transmission lines (509) separated from
substrate (502) by a dielectric material, and that metal core layer (504) meets
the requirement of the claimed thermally conductive element. Fathy teaches
that the metal core layer (504) “provides thermal management, as it is
essentially a built-in heat sink, for efficient spreading of generated heat”
(col. 2, ll. 11-12). As appreciated by the Examiner, and emphasized by
Appellants, Fathy is silent with respect to the distance separating the
adjacent transmission lines and the thickness of the conductive element.
However, while we agree with Appellants that the Examiner improperly
Appeal 2007-1055
Application 10/831,012

4
relies upon Gotro for teaching the separation distance between conductive
elements in separate layers, we agree with the Examiner that one of ordinary
skill in the art would have found it obvious to determine the optimum
spacing between adjacent transmission lines and the thickness of the
conductive element. It is well settled that where patentability is predicated
upon a change in a condition of a prior art feature, such as a change in size,
concentration, or the like, the burden is on the applicant to establish with
objective evidence that the change is critical, i.e., it leads to a new,
unexpected result. In re Woodruff, 919 F.2d 1575, 1578, 16 USPQ2d 1934,
1936 (Fed. Cir. 1990); In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235
(CCPA 1955).
In the present case, Appellants’ specification attaches no particular
criticality to either the distance between adjacent transmission lines or the
thickness of the thermally conductive element. The Specification, at page
11, simply prefers a thickness within the claimed range for the thermally
conductive element, which preference would seem to allay any suggestion of
criticality. Similarly, the Specification, at page 14, only states that the
distance between adjacent transmission lines can be in the range recited in
the appealed claims. While Appellants’ Reply Brief points to figure 4 of the
Specification as evidence of criticality, the Specification merely
demonstrates that a thermally conductive element having a thickness of 1
micron is superior to having no thermally conductive element with respect to
reducing the maximum temperature reached. The Specification provides no
Appeal 2007-1055
Application 10/831,012

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comparison between values within the claimed ranges for separation
distance and thickness and values that would have been used by one of
ordinary skill in the art in devices of the type disclosed by Fathy. Hence,
Appellants have not established with objective evidence that the claimed
distance between adjacent transmission lines and thickness for the thermally
conductive element are critical parameters with respect to providing
unexpected results.
We note that figure 6 of Fathy also depicts a thermally conductive
element (606) and an array of electrical transmission lines (616) separated
from substrate (602) by a dielectric material (604). Appellants maintain that
element (610) of Fathy is not described as being thermally conductive.
Appellants submit that Fathy merely teaches that element (606) is a ground
plane. However, Gotro evidences that it was known in the art that such
power ground planes are used to dissipate heat from electronic components
(see ¶ 0009). Hence, we agree with the Examiner that element (606) of
Fathy qualifies as a thermally conductive element that dissipates heat to at
least the unspecified degree claimed.
Appellants also contend that transmission lines (616) of Fathy “are
embedded in the layer 604, and so are not separated from layer 602 by a
dielectric layer as required by the claims” (Reply Br. 8, third para.).
However, although transmission lines (616) are embedded in dielectric
layer (604), the fact remains that lines (616) are separated from substrate
(602) by the dielectric (604) into which they are embedded.
Appeal 2007-1055
Application 10/831,012

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Regarding separately argued claims 14 and 19 which specify that the
thermally conductive elements are patterned to lie between intersections of
transmission lines, we agree with the Examiner that it would have been
obvious for one of ordinary skill in the art to select any particular pattern for
the thermally conductive elements in the absence of evidence of criticality.
However, Appellants have proffered no such evidence of record.
We will not sustain the Examiner’s § 103 rejection of the appealed
claims over Swanson in view of Gotro. We agree with Appellants that there
is no factual basis for concluding that electrical transmission lines (34) of
Swanson are separated from substrate (30) by a dielectric material. The
Examiner appreciates that the dielectric layer separating the electrical
transmission lines from the substrate is not shown in the drawing but cites
Swanson at col. 4, ll. 15-30. However, we agree with Appellants that there
is no basis for interpreting the relevant portion of Swanson as teaching or
suggesting a dielectric layer between the transmission lines and the
substrate.
In conclusion, based on the foregoing, the Examiner’s decision
rejecting the appealed claims is affirmed.

Appeal 2007-1055
Application 10/831,012

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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)(1)(iv) (2006).
AFFIRMED

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