Google Inc. v. Rockstar Consortium US LP et al

Filing 134

MOTION for Issuance of Letters Rogatory to the Superior Court of Justice of Ontario, Canada for Nortel Networks Corporation, Jean-Pierre Fortin, Angela de Wilton, Jaspreet Harit, Yee-Ning Chan, Brian Finlay Beaton, Bruce Dale Stalkie, Mitch A. Brisebois, Laura A. Mahan, Paul Michael Brennan, Brian Cruickshank, and John Eric Lumsden filed by Google Inc.. (Attachments: # 1 Exhibit A to Google's Notice of Unopposed Motion and Motion for Issuance of Letter Rogatory, # 2 Declaration of Kristin J. Madigan In Support of Google's Unopposed Motion for Issuance of Letter Rogatory, # 3 Exhibit 1, # 4 Exhibit 2, # 5 Exhibit 3, # 6 Exhibit 4, # 7 Exhibit 5, # 8 Exhibit 6, # 9 Exhibit 7, # 10 Exhibit 8, # 11 Exhibit 9, # 12 Exhibit 10, # 13 Exhibit 11, # 14 Exhibit 12, # 15 Exhibit 13, # 16 Exhibit 14, # 17 Exhibit 15, # 18 Exhibit 16, # 19 Exhibit 17, # 20 Exhibit 18, # 21 Exhibit 19, # 22 Exhibit 20, # 23 Exhibit 21, # 24 Proposed Order)(Curran, Patrick) (Filed on 9/29/2014) Modified on 9/30/2014 (cpS, COURT STAFF).

EXHIBIT 18

[18005796] 70A

United States Patent [191

[11]

Patent Number:

Mareantonio

[45]

Date of Patent:

[54] BALL GRID ARRAY (BGA) INTEGRATED
Inventor:

[57]

Gabriel Marcantonio. Nepean. Canada

[73] Assignee: Northern Telecom Limited. Montreal.
Canada

[21] Appl. No.: 601.667
Feb. 15, 1996
[22] Filed:
[51] Int. Cl.‘5 ......................... .. H01L 23/48:

An improved ball grid array (BGA) package having EMI
shielding is provided. In a BGA package a thermally con
ductive heat spreader provided by a conductive layer. and an
electrical interconnection is provided between the electri
cally conductive heat spreader and solder balls of the array.

dielectric body of the package. Thus in use of the package.
HOIL 23/52:

HOlL 29/40
US. Cl. ........................ .. 257/786: 257/780; 257/779;

[5 8]

Field of Search ................................... .. 257/691. 738.

257/691; 257/693
257/659. 780. 781. 786. 706. 779. 698.
693

when contacts are made from the array of solder balls to a
corresponding array of contact areas of a substrate. a ground

connection is simultaneously provided to the heat spreader
through the solder balls. For example. one or more conduc
tive contacts on the substrate may be connected to a ground

plane of the substrate. and a corresponding solder balls of
the package are interconnected to the heat spreader.

Bene?cially. the ground connection is provided by external
rows of solder balls of the array extending around sides of

References Cited

package. or by clusters of solder balls surrounding balls for

carrying signals. Thus by providing integral ground

U.S. PATENT DOCUMENTS
4,954,877
5,371,404

ABSTRACT

for example by plated through holes extending through the

[52]

[5 6]

Aug. 18, 1998

Attomey, Agent. or Firm—Angela C. de Wilton

CIRCUIT PACKAGES

[75]

5,796,170

9/1990 Nakanishj et a]. .................... .. 257/659
12/1994 Juskey ................................... .. 257/659

connections. the heat spreader of the BGA package func
tions also a Faraday shield providing for improved shielding

of electromagnetic interference.

Primary Examiner—lerome Jackson
Assistant Examiner—-S. V. Clark

14 Claims, 4 Drawing Sheets

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Aug. 18, 1998

Sheet 1 of 4

5,796,170

US. Patent

Aug. 18, 1998

Sheet 2 of 4

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US. Patent

Aug. 13, 1998

Sheet 3 0f 4

5,796,170

342

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US. Patent

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Aug. 18, 1998

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5,796,170

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FIG. 8

5.796.170
1

2

BALL GRID ARRAY (BGA) INTEGRATED
CIRCUIT PACKAGES

coupled to received signals. Thus these chips also tend to be
sensitive to RF interference. and spacing between chips

FIELD OF INVENTION

BGA packages provide for many requirements. including
high lead count. heat dissipation and reliability for packag
ing of these chips. existing BGA packages do not provide

must be sul?ciently large to reduce EMI. While existing
This invention relates to improvements in a BGA inte

grated circuit package. and particularly to EMI shielding for

su?icient EMI shielding for this type of application. Addi

a BGA integrated circuit package.

tional EMI shielding in the form of grounded metal covers

may be provided. not only signi?cantly increasing costs. but
also adding bulk to the packaging. For some applications

BACKGROUND OF THE INVENTION

there is not sufficient space to house separate additional

Conventionally. an integrated circuit package provides for

shielding around the package.

electrical connections from an integrated circuit chip to
external conductors. and for protection of the chip from the

external environment. Additionally. management of electro
magnetic emission and thermal dissipation are increasingly
important considerations in the development of improved
packaging for integrated circuits chips. as described in US.

SUMMARY OF THE INVENTION
15

Pat. No. 5.294.826 to the present inventor.

Large integrated circuits. for example. application speci?c
integrated circuits (ASICs) used in telecommunications and
other applications. may dissipate powers in excess of several
Watts. Consequently. it may be necessary to provide an
integrated circuit package with a heat sink. Conventionally
a heat sink for a packaged integrated circuit may be provided
by mounting the chip in thermal contact with a slug of
thermally conductive metal or alloy having an exposed
surface for dissipation of heat. Where greater heat dissipa

conductive material. the heat spreader also being electrically
25

tion is required. a heat sink may be provided with ?ns

prises a conductively plated through hole which conduc
30

package.
To prevent electromagnetic interference (EMI) from
unwanted radiated emissions generated by integrated cir
cuits in electronic equipment. electromagnetic shielding of
electronic systems may be required to meet various regula

35

sions of integrated circuit packages. conventional packaging
techniques are severely challenged in providing both elfec

connection between the solder balls to the internal conduct

ing layers and the heat spreader or heat slug. Side plating is
45

for high lead count integrated circuits. e.g. Application
Speci?c Integrated Circuits (ASICs) for telecommunications
applications. is a Ball Grid Array (BGA) package. This type
of package in now available commercially from a number of

suppliers in various forms for cavity-up or cavity-down
con?gurations. The terminals take the form of arrays of
eutectic solder balls. The solder balls are aligned with
corresponding contact pad areas on a substrate. and heated 55

polyimide. or ceramic dielectric body. Optionally a BGA
package may include a heat spreader for example in the form
of a heat slug. which is typically copper. or another ther
mally conductive metal or alloy. Another type of BGA is
known as a metal BGA (MBGA) which comprise a heat slug

such as copper or copper alloy extending over the surface of

Alternative forms of interconnection between the heat
spreader and solder balls comprises pins or a conductive
connection formed by edge plating to achieve electrical

requirements. may add signi?cant cost to a system.
With the continued drive towards reducing the dimen

BGA package body may comprise a polymer. e.g.

provide Faraday shielding for the BGA package. For
example. the heat spreader comprises a layer of material
having a high thermal conductivity. for example. a metal

through one or more of the solder balls.

ling electromagnetic interference EMI. e.g. FCC

to form contacts directly with the substrate. which allow for
a high density of compact and reliable interconnections. The

tively interconnects the heat spreader and a conductive
contact to the solder balls. Thus the heat spreader may be
interconnected conveniently to a grounding connection to

the package. This material is also electrically conductive.
and thus a the heat spreader may be reliably grounded

tory standards. Addition of shielding to meet increasingly
stringent international regulations and standards for control

tive heat dissipation or control of electromagnetic interfer
ence in a readily manufacturable and reliable package.
One type of package which is now of signi?cant interest

conductive. and comprising a conductive interconnection
provided between the heat spreader and solder balls of the
ball grid array. for providing a ground connection through
the solder balls.
Advantageously. the conductive interconnection com~

extending laterally of the package. to increase the exposed
surface area for heat dissipation. However. the latter
structure. of course. adds considerably to the size of the

The present invention seeks to provide an improved BGA
package for integrated circuits for control of electromagnetic
interference.
Thus according to one aspect of the present invention
there is provided a ball grid array package for an integrated
circuit comprising a dielectric body. an array of solder balls.
and a heat spreader comprising a layer of a thermally

a particularly cost e?°ective method of adapting known

package con?gurations.
The ground connection for the heat spreader is made at the
same time as other interconnections. via the solder balls. A

Faraday shield may be provided without need to provide
separate grounding connections. A reliable ground connec
tion is provided when package is attached to the substrate in
the usual course of assembly. Furthermore. not only is the
substrate area reduced relative to a conventional metal shield

provided over the IC package. space required to provide
external grounding connections is eliminated.
Bene?cially. external rows of solder balls of the array

provide for grounding connections to the heat spreader to
extend around the package to provide an effective grounded

Faraday shield. Alternatively. Faraday shielding may be
provided selectively around single lines by providing
grounding connections thorough selected rows or clusters of

solder balls surrounding balls carrying signals.
According to another aspect of the invention there is

of an anodized metal. e.g. aluminum or copper which forms
provided a ball grid array package for an integrated circuit
a substrate of the package.
65 comprising: a heat spreader comprising a thermally and

For a number of telecommunications applications. inte

grated circuit chips for backplanes may be capacitatively

electrically conductive material; a body of the package for
enclosing an integrated circuit chip in thermal contact with

5.796. I70
3

4

the heat spreader on one side of the body‘, and disposed on

circuit is shown in FIG. 1 and a cross-sectional view through
section II—H of FIG. 1 is shown in FIG. 2. For example. one
such a package is known as the SuperBGATM. manufactured
by Arnkor/Anam. The package 10 for an integrated circuit

an opposite side of the body a metallization layer de?ning
conductive leads on which is disposed an array of solder

balls. conductive interconnections extending through the
body to lead bond pads for the integrated circuit: wherein the
improvement comprises a conductive interconnection
extending between the heat spreader and the array of solder
balls for interconnection of the heat spreader to a ground
connection through the solder balls.
The resulting Faraday shielded BGA package is appli

12 comprises a thermally conductive heat spreader 14.
which is typically a layer of metal. such as thin sheets or
thick slug of a metal such as copper. to which the integrated

circuit 12 is bonded by a thermally conductive die attach
adhesive medium 13. Bond pads 16 of the integrated circuit
are electrically connected via electrically conductive leads

cable to cavity up or cavity down con?gurations. with an
integral heat spreader or an attached heat spreader in the
form of a metal slug. The latter for example includes a cavity

18 to conductive traces 20 de?ned by an electrical conduc

tive layer 28 within the dielectric body of the package
indicated by dielectric layers 24 and 26 of the dielectric

down slug BGA.

body. i.e. a structure similar to that used in printed wiring
board technology. The heat spreader 14 is bonded to one side
of the dielectric body. On the opposite side of the dielectric

According to another aspect of the present invention there
is provided an assembly of a ball grid array package. an
integrated circuit. and a substrate comprising a conductive

body there is provided a conductive layer 27 de?ning

layer providing a ground plane. comprises: the integrated
circuit enclosed within a body of the ball grid array package.
a heat spreader disposed on one side of the body. the heat
spreader being in thermal contact with the integrated circuit;
conductive interconnections extending from contacts pads
of the integrated circuit though conductive leads of the ball
grid array package to corresponding solder balls of the ball
grid array. each solder ball being conductively intercon
nected with a corresponding one of an array of bond pads

conductive traces on which is disposed an array of eutectic
20

25

provided on the substrate. and the heat spreader being
interconnected through conductive leads and the solder balls
to a ground plane of the substrate.

trical interconnections between the solder balls 30 and the
contact pads 16 of the integ'ated circuit. A layer of encap
sulate 32 encloses and protects the integrated circuit 12.
The cross-sectional diagram through part of the BGA in
FIG. 2 shows how the package is interconnected to the
substrate 38 via ball bonds formed by thermal re?ow of the
solder balls 30 to form connections to corresponding indi
vidual contact pads 36 on the substrate. ‘This package has

Thus bene?cially. a grounding connection is reliably
provided at the same time. and preferably in the same

solder balls 30. Conductive vias 31 extend through the layer
24 and 26 forming the dielectric body to provide for elec

one or more levels of metal interconnections. e.g. 120 and
30

manner as other connections of the IC package to the
substrate.

122. in a cavity down con?guration.
Another known type of BOA 100. known as a metal BGA

(MBGA) is shown in FIG. 3. and comprises a metal sub

strate which also serves as a heat spreader 114. The heat
spreader 114 is formed from such materials as anodized
Embodiments of the invention will now be described by
35 aluminum or oxidized copper. the anodization forming a

BRIEF DESCRIPTION OF THE DRAWINGS

way of example. with reference to the accompanying
drawings. in which:
FIG. 1 shows a schematic. oblique view. partially cut
away. diagram of a ball grid array package of the type known
as a SuperBGATM which is made by Amkor/Anam;
FIG. 2 shows an enlarged cross-sectional view through
part of a conventional prior art BGA package;
FIG. 3 shows a cross-sectional view through another
known type of BGA package known as a metal ball grid

array (MBGA) package;

layer 115 coating the metal substrate. Other parts of this
cavity down. single tier MBGA are similar to those of the
BGA in FIG. 2. and for simplicity in comparing the two
structures are labeled with the same reference numerals

incremented by 100.
A cross-sectional diagram through part of a BGA package
200 according to a ?rst embodiment of the present invention
is shown in FIG. 4. In many respects the package of the
embodiment is similar to that shown in FIG. 2. That is. the
45

FIG. 4 shows an cross-sectional view through part of a
BGA package according to a ?rst embodiment of the present

BGA package 200 encloses an integrated circuit chip 212.

invention;

face down in thermal contact with a heat spreader 214.
attached with a layer of thermally conductive material 213.
The heat spreader 214 is provided on one side of the

FIG. 5 shows a cross-sectional view through part of a
BGA package according to a second embodiment of the

226. and 228. Electrically conductive leads 218 interconnect

present invention;

the bond pads 216 of the integrated circuit with electrically

FIG. 6 shows a cross-sectional view through part of a
BGA package according to a third embodiment of the

conductive traces provided by two tiers of conductive layers
220 and 222 extending through the dielectric body. Another
electrically conductive layer 240 is provided on the opposite
surface of the dielectric body and de?nes conductive traces

dielectric body of the package. which comprises layers 224.

present invention;
FIG. 7 shows a cross-sectional view through part of a
BGA package according to an fourth embodiment of the

55

on which are disposed an array of solder balls 230. Electri

cally conductive vias (for simplicity not shown in this
?gure) extend through the dielectric body to interconnect the

present invention; and
FIG. 8 shows a schematic plan view of the array of solder
balls of a BGA package according to another embodiment of

solder balls with the conductive traces within the dielectric

body. The feature which di?’erentiates the BGA package
from conventional known BCA packages is the conductive
interconnection 242. in the form of a plated throughhole.
which provides for electrical connection of the heat spreader

the present invention illustrating an arrangement of ground

connections to provide Faraday shielding selectively around

signal pairs.
DESCRIPTION OF THE PREFERRED
EMBODIMENTS
An oblique. partially cut away view of a known commer

cially available ball grid array package for an integrated

214 to selected solder balls 231 of the array. The heat
65

spreader 214 is provided by a thermally conductive material
which is also electrically conductive. for example a layer of
copper or copper alloy. As shown in FIG. 4. the heat spreader

5.796.170
5

6

is electrically connected through the selected solder balls
balls of the package are provided by conductive pins or side
231 to a ground plane 250 of the substrate 238. i.e. through
plating to achieve electrical connection from the solder balls
an electrical interconnection layer 236 of the substrate and
to the internal conducting layers. and to the heat spreader or
plated through holes 251. Thus the heat spreader 214 is
heat slug. A package 500 of an embodiment comprising the
conveniently grounded. and thereby functions as a Faraday 5 latter type of connection. that is conductive side plating 542
cage to provide EMI shielding. This package may therefore
for grounding the heat spreader 514 is shown schematically
be referred to as a “Faraday BGA package” (FBGA).
in FIG. 7. Thus grounding of the heat spreader and conduc
Conveniently. the ground connection is made at the same
tive side plating 542 conveniently provides for e?’ective
time. and in the same manner. as the other interconnections

Faraday shielding around sides of the package.

to the substrate. i.e.. by re?ow of the solder balls of the array.
Thus a reliable ground connection is provided without

In alternative types of packaging having arrays of con
ductive terminal members other than solder balls. for

additional assembly steps.

example pin grid arrays. e.g. those having stubby pins. or
land grid array packages. a Faraday shield may be provided
by interconnection of a heat spreader or heat slug and

Bene?cially. selected solder balls 231 providing for the
ground connection include the external rows of solder balls

along sides of the package. and surrounding internal rows of
solder balls 230 for carrying signals. Thus the signal lines 15 selected terminal members. e. g. rows or clusters of terminal
members. in an manner analogous to that described above
are effectively enclosed by the Faraday shield comprising
for ball grid array packages.
the heat spreader and the grounding connections.
The packages of the embodiments described above are
Alternatively. where the required number of 1/05 for
shown with wire bonded interconnections between bond
signals limits the number of solder balls available for
pads of the integrated circuit chip and conductive elements
making grounding connections. rather than grounding all
of the package. Alternative ball grid array package con?gu
external rows of balls. rows of solder balls on selected sides
rations include those in which the chip is interconnected by
of the array. e.g. along three sides of the package body. may
?ip chip or TAB (tape automated bonding) technologies.
provide for grounding. and rows on other sides provide for
The Faraday BGA packages according to the embodi
signals. In other variations. grounding of selected clusters or
ments described above are based on plastic BGA packages
groups of solder balls surrounding balls carrying signals
using polymer dielectrics. Alternative embodiments are pro
provides for selectively shielding signal lines. Grounding
may be provided alternatively by internal groups or rows of
solder balls of the array. as required. as shown schematically
in FIG. 8. wherein balls shown as solid back represent
ground connections. which surround signal pairs marked + 30
and —. Thus. as shown in dotted outline. a Faraday shield is

provided around signal I/Os e.g. solder balls D2'E2 and
D13/E13 which are surrounded by ground connections

vided based on ceramic BGA structures. Other alternative
embodiments are based on metal BGA packages in which

the metal substrate forming the heat spreader is grounded as
in the embodiments described above. to provide the Faraday

shielding.
Thus. it will be appreciated that. while speci?c embodi
ments of the invention are described in detail above. numer
ous variations and modi?cations of these embodiments fall

(black).
The EMI shielded package is provided in a reduced area

within the scope of the invention as defined in the following

relative to that occupied by a chip having an additional
conventional grounded metal shielding provided over the
package. and avoids the need for additional external ground
ing posts to be provided in a separate assembly step. Thus.
the resulting package is cost e?ective and provides for

claims.
What is claimed is:
1. A ball grid array package for an integrated circuit
comprising a dielectric body. a heat spreader disposed on
one side of the dielectric body comprising a layer of a

compact Faraday shielding.

thermally conductive material. the heat spreader also being

electrically conductive.

While the embodiment described above includes an inte

gral heat spreader provided as part of the package. packages

the dielectric body surrounding a die attach area on the

according to alternative embodiments are provided with 45
separate bonded heat spreaders i.e. in the form of a bonded
copper slug. and/or alternative conductive means for inter
connecting a heat spreader or heat slug to solder balls of the
package. as shown in FIGS. 5 to 7.
Thus in a BGA package 300 according to a second 50
embodiment shown in part in FIG. 5 a separate heat spreader

314 is provided in the form of a copper slug 314 which is
soldered to the package body. This embodiment comprises
ground connections 342 as shown. interconnecting the cop
per slug 314 and solder balls 331. Parts of interconnect
layers 322 also provide for a Vss end ring shields. Intercon
nect vias 321 extend between the interconnect layers 320
and 322.
Another package 400 according to a third embodiment.

55

comprising:
a heat spreader comprising a thermally and electrically
conductive material;
a body of the package for enclosing an integrated circuit
chip in thermal contact with the heat spreader disposed

in the con?gurations of the internal interconnection layers.
The ground connection 442 for the heat spreader 414 is
provided by a conductively plated through hole similar to
In other packages according to alternative embodiments
the interconnection between the heat spreader and the solder

a plurality of solder balls of a ball arid array provided
on the other side of the dielectric body. and
a conductive interconnection provided between the heat
spreader and selected solder balls of the ball grid array.
for providing a ground connection to the heatstreader

through the solder balls.
2. A ball grid array package for an integrated circuit

also based on a super BGA con?guration is shown in FIG. 60
9. The latter differs from that of the ?rst embodiment only

that of the ?rst embodiment.

heatspreader. and providing a plurality of bond pads for
wirebonding of the integrated circuit. and interconnec
tion from the bond pads through the dielectric body to

on one side of the body;
and disposed on an opposite side of the body a metalli

zation layer de?ning conductive leads on which is
disposed an array of solder balls. conductive intercon

nections extending through the body from solder balls
65

of the array to lead bond pads for the integrated circuit;
wherein the improvement comprises a conductive inter

connection extending between the heat spreader

5.796.170
8

7

10. An assembly according to claim 9 wherein the con—
ductive interconnections between the heat spreader and the

through the body to selected solder balls the array. for
interconnection of the heat spreader to a ground con

selected solder balls comprise plated through holes extend
ing through the dielectric body.

nection through the array of solder balls.
3. A BGA package according to claim 1 wherein selected
solder balls comprise an external row of solder balls of the

11. An assembly according to claim 9 wherein the con
ductive interconnections between the heat spreader and the

array extending along sides of the array of solder balls.
4. A BGA package according to claim 1 wherein selected
solder balls providing for grounding of the heater heat

selected solder balls comprise conductive pins extending
through the dielectric body.

spreader comprise a cluster of solder balls surrounding
solder balls for carrying signals.

12. An assembly according to claim 9 wherein the con
ductive interconnection between the heat spreader and the

5. A BGA package according to claim 1 wherein the
conductive interconnection comprises a plated through hole

selected solder balls comprise conductive side plated regions
of the dielectric body of the package.
13. A ball grid array package for an integrated circuit

extending through the dielectric body and interconnecting
the heat spreader and selected solder balls of the array.
6. A BGA package according to claim 1 wherein the
conductive interconnection comprises a conductive pin

15

heat spreader comprising a layer of a thermally conductive
material disposed on an opposite side of the dielectric body.

extending through the dielectric body and interconnecting
the heat spreader and selected solder balls of the array.
7. A BGA package according to claim 1 wherein the
conductive interconnection comprises a side plated inter
connection extending over a surface of the dielectric body to
interconnect the heat spreader and selected solder balls of

20

package. and
25

ing over a surface of the package.
9. An assembly of a ball grid array package. an integrated
circuit. and a substrate comprising a conductive layer pro
30

an electrically conductive heatspreader disposed on one
side of the body. and an array of solder balls disposed
on an opposite side of the body. the integrated circuit

enclosed by the heatspreader and the dielectric body of
the ball grid array package;

35

conductive interconnections extending from contact pads
of the integrated circuit though conductive leads

heat spreader comprising a layer of a thermally conductive
material disposed on an opposite side of the dielectric body.
tric body from solder balls of the ball grid array to bond
pads for interconnecting an integrated circuit within the

extending through the dielectric body of the ball grid

package. and

array package to corresponding individual solder balls

other conductive interconnections provided between the

of an array of solder balls;

and the heat spreader being interconnected through con

connection to the integrated circuit.
14. A ball grid array package for an integrated circuit

the heat spreader also being electrically conductive.
conductive interconnections extending through the dielec

integrated circuit;

on the substrate.

grid array package surrounding solder balls for inter
comprising a dielectric body. an array of solder balls of a ball
grid array disposed on one side of the dielectric body. and a

and the heat spreader being in thermal contact with the

each solder ball being conductively interconnected with a
corresponding one of an array of bond pads provided

other conductive interconnections provided between the
heat spreader and selected other solder balls of the ball
grid array. for providing a ground connection to the
heatspreader. the selected other solder balls comprising
rows of solder balls around external edges of the ball

viding a ground plane. comprising:
the ball arid array package comprising a dielectric body.

the heat spreader also being electrically conductive.
conductive interconnections extending through the dielec
tric body from solder balls of the ball grid array to bond
pads for interconnecting an integrated circuit within the

the array.
8. A BGA package according to claim 1 wherein the heat

spreader comprises a layer of copper or copper alloy extend

comprising a dielectric body. an array of solder balls of a ball
grid array disposed on one side of the dielectric body. and a

heat spreader and selected other solder balls of the ball
grid array. for providing a ground connection to the
45

heatspreader. the selected other solder balls comprising
a cluster of solder balls arranged around solder balls for

carrying signals to the integrated circuit.

ductive interconnections to selected solder balls con

nected to the ground plane of the substrate.

*

*

*

*

*