U.S. patent application number 09/182287 was filed with the patent office on 2001-08-23 for microcircuit shielded, controlled impedance "gatling gun" via.
This patent application is currently assigned to AGILENT TECHNOLOGIES. Invention is credited to BARNETT, RON, CASEY, JOHN F., DOVE, LEWIS R..
Application Number | 20010015288 09/182287 |
Document ID | / |
Family ID | 22667816 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010015288 |
Kind Code |
A1 |
DOVE, LEWIS R. ; et
al. |
August 23, 2001 |
MICROCIRCUIT SHIELDED, CONTROLLED IMPEDANCE "GATLING GUN" VIA
Abstract
A "Gatling gun" via to interconnect circuitry from a first side
of a substrate or printed circuit board, to a second side of the
substrate or board. The present via structure comprises a center
conductor via surrounded by a plurality of ground vias. The
plurality of ground vias shield the center conductor via, thus
providing electrical isolation for the conductor via from the rest
of the circuitry. In one embodiment, the conductor via is
electrically connected to a conductive pattern on the substrate by
a wire bond.
Inventors: |
DOVE, LEWIS R.; (MONUMENT,
CO) ; CASEY, JOHN F.; (COLORADO SPRINGS, CO) ;
BARNETT, RON; (ST SANTA ROSA, CA) |
Correspondence
Address: |
AGILENT TECHNOLOGIES, INC.
INTELLECTUAL PROPERTY ADMINISTRATION, LEGAL DEPT.
P.O. BOX 7599
M/S DL429
LOVELAND
CO
80537-0599
US
|
Assignee: |
AGILENT TECHNOLOGIES
|
Family ID: |
22667816 |
Appl. No.: |
09/182287 |
Filed: |
October 29, 1998 |
Current U.S.
Class: |
174/262 ;
174/266 |
Current CPC
Class: |
H01L 24/48 20130101;
H01L 2924/00014 20130101; H01L 2224/45014 20130101; H01L 2924/206
20130101; H01L 2224/45099 20130101; H01L 2924/00014 20130101; H01L
2924/00 20130101; H01L 2924/00014 20130101; H01L 2224/45015
20130101; H01L 2924/207 20130101; H01L 2924/00014 20130101; H01L
2924/14 20130101; H01L 2224/48091 20130101; H01L 2924/01078
20130101; H01L 2224/48091 20130101; H01L 2924/00014 20130101; H01L
2223/6622 20130101; H01L 2924/01068 20130101; H05K 1/0222 20130101;
H05K 2201/09618 20130101; H05K 2201/09809 20130101; H05K 3/42
20130101; H01L 2924/01039 20130101; H01L 2924/3025 20130101; H01L
2224/85399 20130101; H01L 2223/6616 20130101; H01L 2224/05599
20130101; H05K 2203/049 20130101; H01L 2224/05599 20130101; H01L
2924/3011 20130101; H01L 2924/14 20130101; H01L 2224/45014
20130101; H01L 23/66 20130101; H01L 2924/00014 20130101; H01L
2224/85399 20130101; H01L 2924/00014 20130101 |
Class at
Publication: |
174/262 ;
174/266 |
International
Class: |
H05K 001/11 |
Claims
What is claimed is:
1. A interconnection structure to connect a first side of a circuit
board to a second side of the circuit board, the structure
comprising: a center conductor via; and a plurality of ground vias,
said plurality of ground vias substantially surrounding the
conductor via, wherein the conductor via propagates electrical
signals from the first side to the second side of the circuit
board.
2. The interconnection structure of claim 1, further comprising: a
wire bond, the wire bond electrically connected to the conductor
via at a first end and a conductive pattern at a second end.
3. A interconnection structure to connect a first side of a
substrate to a second side of the substrate, the structure
comprising: a center conductor via; a plurality of ground vias,
said plurality of ground vias substantially surrounding the
conductor via, and a wire bond, the wire bond electrically
connected to the conductor via at a first end and a conductive
pattern at a second end, the conductive pattern formed on the first
side of the substrate, wherein the conductor via propagates
electrical signals from the first side to the second side of the
substrate.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to microcircuits and
more particularly to a "Gatling gun" via, that is a via having a
center conductor via surrounded by ground vias.
BACKGROUND OF THE INVENTION
[0002] Today's complex integrated circuits typically employ of
several million transistors on a single integrated circuit
substrate. Multiple layers of conductive material are formed
overlying the substrate in order for these millions of transistors
to interconnect and work as a whole. To facilitate electrical
communication between conductive layers, via structures are used.
Vias are openings etched through dielectric layers between a first
conductive layer and a second conductive layer.
[0003] Circuit board interconnects generally fall into three
categories. The first category employs a laminated epoxy-filled
cloth. The individual layers have electronically conductive paths
of patterned copper. The second category uses a base structure of
epoxy filled-cloth. This base is then covered with multiple layers
of photoimageable dielectric and patterned copper. The third
category is composed of multiple layers of laminated ceramic, with
individually patterned copper. The present invention is directed to
the formation of "Gatling gun" vias with reference to the second
category, although the concepts herein can apply to the other two
interconnect schemes.
[0004] Vias can be formed by drilling holes and then plating the
paths through the holes. The via holes can extend through the
complete multilayer board. In this configuration, the vias are
electrically coupled to each copper (i.e., conductive) layer.
Alternatively, vias can be formed using a conventional
photoimage-generated via structure.
[0005] One problem with via structures employed in high frequency
applications is the lack of AC electrical isolation between the via
and the remainder of the microcircuit. Another problem is that
standard vias (formed either by drilling or by photoimaging) do not
provide a controlled impedance environment at high frequencies.
SUMMARY OF THE INVENTION
[0006] The present invention provides a "Gatling gun" via to
interconnect circuitry from a first side of a substrate or printed
circuit board, to a second side of the substrate or board. The
present via comprises a center conductor via surrounded by a
plurality of ground vias. The plurality of ground vias shield the
center conductor via, thus providing electrical isolation for the
conductor via from the rest of the circuitry. One feature of the
present invention is that the plurality of ground vias can be
modified, adjusting their diameters and their placement relative to
the center conductor via, in order to affect the overall
characteristic impedance of the Gatling gun via. This feature is
useful when propagating high frequency signals from the first side
to the second side of the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 shows a schematic cross-sectional view of a laminated
epoxy core structure with a Gatling gun via according to the
present invention.
[0008] FIG. 2 shows a top view of the Gatling gun via.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0009] Richard J. Gatling was born in 1818 in North Carolina,
U.S.A. In his early 20s, Gatling invented and improved upon many
agricultural implements, including a machine for sowing cotton and
a steam-driven plow. But Gatling is probably best remembered for
inventing a rapid-firing gun that bears his name.
[0010] Following the outbreak of the American Civil War, Gatling
became interested in firearms. In 1862 he patented the hand-crank,
rapid fire Gatling gun. The first Gatling gun has six rifle barrels
mounted around a central shaft. The barrels rotated around the
shaft while the gun was operating. Each barrel was mechanically
loaded once at the top of a rotation and fired once at the bottom
of a rotation. The empty shell was ejected as the barrel advanced
up towards a reload. Early models of the Gatling gun fired
approximately 300 rounds per minute. By 1882, Gatling improved upon
his design so that the gun fired 1200 rounds per minute.
[0011] The design of the Gatling gun inspires the present
invention. The model of a plurality of barrels around a central
shaft is adopted in an improved via structure that provides better
isolation and improved controlled impedance for electrically
interconnecting circuitry from a first side of a substrate or
printed circuit board, to circuitry on a second side of the
substrate or board. The discussion below will disclose the present
invention in a printed circuit board environment. But one skilled
in the art will appreciate the present invention's applicability in
a wide variety of applications, including single layer and
multi-layer substrates and ceramic.
[0012] FIG. 1 shows a schematic cross-sectional view of a laminated
epoxy core structure with a Gatling gun via. A base or core
laminate of multiple epoxy-filled cloth layers 110 has formed on
its topside 112 a pattern of electrically conductive copper 120
while on its backside 114, another pattern of electrically
conductive copper 122 is formed. Patterns of copper (items 124 and
126) are also formed on the laminate 110 which are electrically
tied to ground as will be discussed more fully below. The patterns
(items 120, 122, 124 and 126) are generally disposed in x- and
y-direction planes.
[0013] The cross section also shows three drilled holes at 130, 132
and 134 extending through the base laminate 110 as well as the
copper patterns 120, 122, 124 and 126. Holes 130, 132 and 134 are
generally disposed in a z-direction, interplanar to the patterns
120, 122, 124 and 126.
[0014] Once the holes are drilled, a dry film (not shown) can be
vacuum laminated to the backside 114 in a conventional manner. The
hole at 130 is then filled with conductive, plateable and
solderable polymer (not shown) which can be applied as a paste or
liquid in a conventional manner. The polymer is then cured and the
dry film is stripped. This then forms the center conductor via at
130. In a similar manner, the holes at 132 and 134 are filled and
cured.
[0015] A wire bond 140 electrically connects the center conductor
via 130 to the electrically conductive pattern 120. In another
preferred embodiment, the wire bond 140 could be a ribbon bond or
dielectric tape or any material that will be able to propagate an
electrical signal from the center conductor 130, over the ground
via 132 to the electrically conductive pattern 120.
[0016] FIG. 2 shows a top view of the Gatling gun via according to
the present invention. The center conductor via 130 is surrounded
by a plurality of ground vias 132, 134 and 232. A space 220
isolates the conductor via 130 from a ground plane 210 which
electrically grounds the plurality of ground vias 132, 134 and
236.
[0017] FIG. 2 illustrates the center conductor 130 being surrounded
by eight ground vias. This number is not terribly important.
Isolation could be accomplished with as little as two vias.
Increasing the number of ground vias, increases electrical
isolation. Controlling the impedance of the structure is
accomplished by varying the diameters of the conductor and ground
vias, as well as their relative position from each other. One
benefit of the present invention is that propagation of signals in
a package employing the Gatling gun vias is enhanced while
minimizing cross talk between signal conductors and power
distribution noise. Use of the Gatling gun via also permits the
circuit designer to tighten the space between two circuit regions,
for example.
* * * * *