U.S. patent application number 10/335649 was filed with the patent office on 2004-07-01 for termination ring for integrated circuit.
Invention is credited to Al-Dabagh, Maad, Antisseril, Thomas, Ratchkov, Radoslav, Shen, Bo, Subbarao, Prasad.
Application Number | 20040124521 10/335649 |
Document ID | / |
Family ID | 32326051 |
Filed Date | 2004-07-01 |
United States Patent
Application |
20040124521 |
Kind Code |
A1 |
Al-Dabagh, Maad ; et
al. |
July 1, 2004 |
TERMINATION RING FOR INTEGRATED CIRCUIT
Abstract
A rectangular termination ring for a power distribution mesh is
placed on the upper two layers of an integrated circuit and may be
placed over some I/O circuitry. The strapping connecting the
bonding pads to the termination ring are placed on upper levels of
the integrated circuit, minimizing the via requirements and freeing
space for additional circuitry. Further, the termination ring may
be adapted to work in conjunction with L-shaped, as well as other
power distribution meshes.
Inventors: |
Al-Dabagh, Maad; (San Jose,
CA) ; Antisseril, Thomas; (Newark, CA) ; Shen,
Bo; (Fremont, CA) ; Subbarao, Prasad; (San
Jose, CA) ; Ratchkov, Radoslav; (Santa Clara,
CA) |
Correspondence
Address: |
The Law Offices of William W. Cochran, LLC
Suite 230
3555 Stanford Road
Fort Collins
CO
80525
US
|
Family ID: |
32326051 |
Appl. No.: |
10/335649 |
Filed: |
December 31, 2002 |
Current U.S.
Class: |
257/691 ;
257/E23.153 |
Current CPC
Class: |
H01L 2924/14 20130101;
H01L 23/5286 20130101; H01L 2924/14 20130101; H01L 24/06 20130101;
H01L 2924/00 20130101 |
Class at
Publication: |
257/691 |
International
Class: |
H01L 023/52 |
Claims
What is claimed is:
1. A power distribution system for an integrated circuit die
comprising: a first electrically conductive ring about the
periphery of said die wherein said first ring is located above at
least one I/O circuit; a second electrically conductive ring
substantially inwardly offset from said first ring and positioned
on the layer below the layer of said first ring; a first connection
from said first ring to a first bonding pad wherein at least a
continuous electrical connection is located in the same layer as
said first ring; and a second connection from said second ring to a
second bonding pad wherein at least a continuous electrical
connection is located in the same layer as said second ring.
2. The power distribution system of claim 1 wherein said first ring
is placed on the topmost layer of said die.
3. The power distribution system of claim 1 wherein said first ring
is substantially concentric with the edges of said die.
4. The power distribution system of claim 1 wherein said power
distribution system is adapted to connect to an L-shaped power
distribution mesh.
5. The power distribution system of claim 1 wherein said power
distribution system is adapted to connect to a radially varying
power distribution mesh.
6. The power distribution system of claim 1 wherein a plurality of
first bonding pads are connected to said first ring by a plurality
of said first connections.
7. The power distribution system of claim 1 wherein a plurality of
second bonding pads are connected to said second ring by a
plurality of said second connections.
8. The power distribution system of claim 1 further comprising: a
third ring substantially inwardly offset from said second ring and
positioned on said layer below said layer of said first ring; and
at least one connection from said first ring to said third
ring.
9. An integrated circuit with a power distribution system
comprising: a first electrically conductive ring about the
periphery of the die of said integrated circuit wherein said first
ring is located above at least one I/O circuit; a second
electrically conductive ring substantially inwardly offset from
said first ring and positioned on the layer below the layer of said
first ring; a first connection from said first ring to a first
bonding pad wherein at least a continuous electrical connection is
located in the same layer as said first ring; and a second
connection from said second ring to a second bonding pad wherein at
least a continuous electrical connection is located in the same
layer as said second ring.
10. The power distribution system of said integrated circuit of
claim 9 wherein said first ring is placed on the topmost layer of
said die.
11. The power distribution system of said integrated circuit of
claim 9 wherein said first ring is substantially concentric with
the edges of said die.
12. The power distribution system of said integrated circuit of
claim 9 wherein said power distribution system is adapted to
connect to an L-shaped power distribution mesh.
13. The power distribution system of said integrated circuit of
claim 9 wherein said power distribution system is adapted to
connect to a radially varying power distribution mesh.
14. The power distribution system of said integrated circuit of
claim 9 wherein a plurality of first bonding pads are connected to
said first ring by a plurality of said first connections.
15. The power distribution system of said integrated circuit of
claim 9 wherein a plurality of second bonding pads are connected to
said second ring by a plurality of said second connections.
16. The power distribution system of said integrated circuit of
claim 9 further comprising: a third ring substantially inwardly
offset from said second ring and positioned on said layer below
said layer of said first ring; and at least one connection from
said first ring to said third ring.
17. An integrated circuit with a power distribution system
comprising: a first electrically conductive power distribution
means about the periphery of the die of said integrated circuit
wherein said first electrically conductive power distribution means
is located above at least one I/O circuit; a second electrically
conductive power distribution means substantially inwardly offset
from said first electrically conductive power distribution means
and positioned on the layer below the layer of said first
electrically conductive power distribution means; a first
connection means from said first electrically conductive power
distribution means to a first off-die connection means wherein at
least a continuous electrical connection is maintained in the same
layer as said first electrically conductive power distribution
means; and a second connection means from said second electrically
conductive power distribution means to a second off-die connection
means wherein at least a continuous electrical connection is
maintained in the same layer as said second electrically conductive
power distribution means.
18. The power distribution system of said integrated circuit of
claim 17 wherein said first off-die connection means comprises a
bonding pad.
19. The power distribution system of said integrated circuit of
claim 17 wherein said second off-die connection means comprises a
bonding pad.
20. The power distribution system of said integrated circuit of
claim 17 wherein said first electrically conductive power
distribution means is placed on the topmost layer of said die.
21. The power distribution system of said integrated circuit of
claim 17 wherein said first electrically conductive power
distribution means is substantially concentric with the edges of
said die.
22. The power distribution system of said integrated circuit of
claim 17 wherein said power distribution system is adapted to
connect to an L-shaped power distribution mesh.
23. The power distribution system of said integrated circuit of
claim 17 wherein said power distribution system is adapted to
connect to a radially varying power distribution system.
24. The power distribution system of said integrated circuit of
claim 18 wherein a plurality of first bonding pads are connected to
said first ring by a plurality of said first connections.
25. The power distribution system of said integrated circuit of
claim 19 wherein a plurality of second bonding pads are connected
to said second ring by a plurality of said second connections.
26. The power distribution system of said integrated circuit of
claim 17 further comprising: a third electrically conductive power
distribution means substantially inwardly offset from said second
electrically conductive power distribution means and positioned on
said layer below said layer of said first power electrically
conductive distribution means; and at least one electrically
conductive connection from said first electrically conductive power
distribution means to said third electrically conductive power
distribution means.
Description
BACKGROUND OF THE INVENTION
[0001] a. Field of the Invention
[0002] The present invention pertains to wiring within integrated
circuits and specifically to power distribution circuits within
integrated circuits.
[0003] b. Description of the Background
[0004] An integrated circuit (IC) typically includes two or more
layers dedicated to power distribution. The power distribution
layers may have various arrangements for grossly transmitting
current throughout the IC to the various cells that require
power.
[0005] Various power distribution meshes are known in the art.
Examples are U.S. Pat. No. 6,346,721 entitled "Integrated Circuit
Having Radially Varying Power Bus Grid Architecture" by Schultz,
U.S. Pat. No. 6,111,310 entitled "Radially Increasing Core Power
Bus Grid Architecture" by Schultz, copending and commonly assigned
U.S. patent application Ser. No. 09/948,190 entitled "Power
Redistribution Bus for a Wire Bonded Integrated Circuit" by
Schultz, et al., filed Sep. 7, 2001, copending and commonly
assigned U.S. patent application Ser. No. 09/968,286 entitled "Die
Power Distribution Bus" by Ali, et al, filed Oct. 1, 2001, all of
which are hereby specifically incorporated herein by reference for
all they disclose and teach.
[0006] In general, these distribution meshes address the
transmittal of current to the inside portions of a die. However,
there is need in the art for an improved termination ring that
provides the distributed current to the periphery of the mesh.
[0007] One type of IC is known as an Application Specific
Integrated Circuit (ASIC). The design of ASICs comprises many
pre-designed circuits that are connected to create the necessary
logic and circuitry for the specific task. One type of pre-designed
circuit is an I/O circuit. The I/O circuit is the circuitry that is
close to the bonding pad. Recent designs have increased the size of
the I/O circuits, known as `tall I/O`, referring to the length of
the rectangular shape of the I/O circuits.
[0008] In older ASIC designs, it had been commonplace to place a
termination ring for a power distribution mesh inside of the I/O
circuits for a number of reasons. However, as the size of some of
the I/O circuits has grown, it has become impractical to adhere to
this design rule. As such, rectilinear termination rings have been
designed to avoid the tall I/O circuits by changing shape to
meander around the tall I/O. These types of termination rings may
occupy more space on the die than necessary and thus may cause the
die to be larger to accommodate the larger termination ring.
Further, as the I/O circuits become taller, the termination ring is
placed further inward, causing a longer distance for the power to
travel from a bonding pad to the termination ring. The increased
distance causes the trace or strap from the bonding pad to the
termination ring to become wider and may increase the number of
bonding pads required for transmitting sufficient current to the
termination ring. In some cases, the number of bonding pads
required for the specific application may determine the size of the
die. In such cases, increases in the number of bonding pads may
increase the die size, adding to the cost of the resultant IC.
[0009] The design convention has been that I/O circuits have been
placed in lower metal layers of the IC. Further, the traces from
the bonding pads to the termination ring have been commonly
incorporated into special I/O circuits known as power I/O. The
traces or straps that transfer the current from the outside of the
die to the termination ring within the die require vias to transfer
the current between layers. The size and depth of the vias
necessarily take up space within the die that is otherwise
useable.
[0010] It would therefore be advantageous to provide a system and
method for a power termination ring in an integrated circuit that
requires a minimum of space on the periphery of the die. It would
further be advantageous to provide a termination ring that
accommodated tall I/O circuits as well as occupied a minimum amount
of space within and integrated circuit so that additional circuitry
may be placed in an IC without increasing the size of the IC.
SUMMARY OF THE INVENTION
[0011] The present invention overcomes the disadvantages and
limitations of the prior art by providing a system and method for
placing a termination ring and straps in the top two layers of an
integrated circuit. The termination ring may be placed over I/O
circuits so that the distance between a bonding pad and the
termination ring is minimized. Further, the termination ring
architecture is adapted to L-shaped power distribution meshes as
well as other power distribution meshes.
[0012] The present invention may therefore comprise a power
distribution system for an integrated circuit die comprising: a
first electrically conductive ring about the periphery of the die
wherein the first ring is located above at least one I/O circuit; a
second electrically conductive ring substantially inwardly offset
from the first ring and positioned on the layer below the layer of
the first ring; a first connection from the first ring to a first
bonding pad wherein at least a continuous electrical connection is
located in the same layer as the first ring; and a second
connection from the second ring to a second bonding pad wherein at
least a continuous electrical connection is located in the same
layer as the second ring.
[0013] The present invention may further comprise an integrated
circuit with a power distribution system comprising: a first
electrically conductive ring about the periphery of the die of the
integrated circuit wherein the first ring is located above at least
one I/O circuit; a second electrically conductive ring
substantially inwardly offset from the first ring and positioned on
the layer below the layer of the first ring; a first connection
from the first ring to a first bonding pad wherein at least a
continuous electrical connection is located in the same layer as
the first ring; and a second connection from the second ring to a
second bonding pad wherein at least a continuous electrical
connection is located in the same layer as the second ring.
[0014] The present invention may further comprise an integrated
circuit with a power distribution system comprising: a first
electrically conductive power distribution means about the
periphery of the die of the integrated circuit wherein the first
electrically conductive power distribution means is located above
at least one I/O circuit; a second electrically conductive power
distribution means substantially inwardly offset from the first
electrically conductive power distribution means and positioned on
the layer below the layer of the first electrically conductive
power distribution means; a first connection means from the first
electrically conductive power distribution means to a first off-die
connection means wherein at least a continuous electrical
connection is maintained in the same layer as the first
electrically conductive power distribution means; and a second
connection means from the second electrically conductive power
distribution means to a second off-die connection means wherein at
least a continuous electrical connection is maintained in the same
layer as the second electrically conductive power distribution
means.
[0015] The advantages of the present invention are that a minimum
of space within an integrated circuit is used to transfer current
from the bonding pads to a power distribution mesh. Certain
critical spaces, such as the area around the periphery of the
integrated circuit die and the area from the bonding pads to the
termination ring are minimized so that the size of the die may be
minimized and additional circuitry may be placed in the integrated
circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In the drawings,
[0017] FIG. 1 is an illustration of an embodiment of the present
invention wherein an integrated circuit die has an outer
distribution ring, and inner distribution ring, and an optional
third distribution ring.
[0018] FIG. 2 is an illustration of an embodiment of the present
invention wherein an L-shaped mesh is incorporated with the
distribution rings.
[0019] FIG. 3 is an illustration of an embodiment of the present
invention wherein an V-shaped mesh is incorporated with the
distribution rings.
[0020] FIG. 4 is a three dimensional representation of an
embodiment of a power distribution system.
DETAILED DESCRIPTION OF THE INVENTION
[0021] FIG. 1 illustrates an embodiment 100 of the present
invention wherein an integrated circuit die 102 has an outer
distribution ring 104, and inner distribution ring 106, and an
optional third distribution ring 107. The three rings 104, 106, and
107 are positioned over several tall I/O circuits 108. The bonding
pads 110 connect to the rings 104 and 107 through the strap
118.
[0022] The embodiment 100 takes the current provided on the bonding
pads 110, 112, 114, and 116 and distributes the current around the
periphery of the die 102. The use of a peripheral ring to
distribute current allows various meshes known in the art to
transfer current throughout the die.
[0023] In the present embodiment, the outer ring 104 may be placed
on the top layer of the die, where the metal traces may be thicker
than on other layers. The inner rings 106 and 107 may be placed on
the next layer below that of the outer ring 104. In other
embodiments, the outer ring 104 may be on another layer other than
the topmost layer. In still other embodiments, the inner rings 106
and 107 may be on the layer above the outer layer 104.
[0024] Some mesh designs have a primary layer. For example, an
L-shaped mesh has a single layer in which most of the power
distribution traces reside. Such a layer would be the primary layer
of the mesh. Other mesh designs may require two or more planes, and
may not have a singular primary plane. In embodiments with a single
primary layer, the primary layer of the mesh will generally be on
the same layer as the outermost ring.
[0025] The straps 118 may be on the same layers as the respective
rings to which they are attached. Other traces may exist below or
above the layers on which the straps exist. However, the primary
current path may be within the layer of the respective distribution
ring. For example, the straps associated with bonding pads 110 and
114 may be in the same layer as the outer ring 104.
[0026] In some embodiments, the straps may comprise traces on a
plurality of layers. For example, a strap 118 may comprise a trace
on the top layer and a substantially identical trace on the layer
below. A series of vias may be present to connect the top trace
with the bottom trace, effectively making a thicker connection to
handle increased currents with less resistance.
[0027] The embodiment 100 shows two bonding pads associated with
each distribution ring. In different embodiments, those skilled in
the art will appreciate that more or less bonding pads and straps
may be required depending on the amount of current to be supplied
to the mesh.
[0028] The outer ring 104 is shown placed above the tall I/O
circuits 108. The placement of the rings 104, 106, and 107 over the
I/O circuits 108 means that the rings 104, 106, and 107 may be
further toward the edges of the die 102. By moving the current
distribution rings 104, 106, and 107 outward, the distance between
the bonding pad 110 and the ring 104 is minimized. This means that
the width and thickness of the straps may be lessened because the
straps induce less resistance when they are shorter in length. In
some designs, moving the rings outward may eliminate the need for
one or more straps, freeing up some space for an additional I/O
circuit or causing the integrated circuit to be designed on a
smaller die.
[0029] The third ring 107 is an optional ring. In some embodiments,
the third ring 107 may not be present, and the outer ring 104 may
be sufficient to carry the current load.
[0030] FIG. 2 illustrates an embodiment 200 of the present
invention wherein an L-shaped mesh is shown. The integrated circuit
die 202 has an outer distribution ring 204, an inner distribution
ring 206, and an optional third ring 208. As with embodiment 100,
bonding pads 210, 212, 214, and 216 are connected to the various
rings. The traces 218 and 219 represent traces connected to the
outer distribution ring 204. The trace 220 is likewise connected to
the inner ring 206. The layer for the mesh traces 218 and 220 may
be the same layer as the outermost ring 204. The trace 220 may be
connected to the inner ring 206 with vias 220 and 224.
[0031] In the embodiment 200, the primary layer of the mesh is the
layer in which the traces 218 and 220 reside. The primary layer is
also the layer in which the outer ring 204 resides.
[0032] The interior of the third ring 208 is free for other trace
routing. In some embodiments, the area within the third ring 208
may be necessary for the normal connections amongst the circuitry
of the integrated circuit. As the power distribution design frees
up more area, more functionality may be incorporated into the
integrated circuit while maintaining the same die size.
[0033] FIG. 3 illustrates an embodiment 300 of a power distribution
system utilizing a V-shaped mesh. The integrated circuit die 302
contains an outer ring 304, an inner ring 306, and an optional
third ring 308 in a similar fashion to embodiments 100 and 200
discussed above. The bonding pads 310 are similar to those of
embodiments 100 and 200.
[0034] The trace 312 is connected to the outer ring 304 and the
third ring 308 by vias 314, 316, 318, and 320. Trace 322 is
connected to the inner ring 306 by vias 324 and 326. The other
traces shown are alternatively connected to the inner ring 304 and
the outer ring 306 to distribute power throughout the chip.
[0035] Embodiment 300 illustrates how different mesh designs may be
used with multiple distribution rings. Those skilled in the art may
envision many different mesh designs that may be similarly
incorporated into the present multiple ring design.
[0036] FIG. 4 illustrates a three dimensional representation of an
embodiment 400 of a power distribution system. The outer ring 402
is located on an upper level whereas the inner ring 404 and
optional third ring 406 are located on a lower level, typically the
next layer below that of the outer ring 402. The rings 402, 404,
and 406 are located over I/O circuitry that is represented by boxes
408 and 410.
[0037] The pad strap 412 connects a bonding pad (not shown) to the
inner ring 404. The pad strap 412 may comprise an upper trace 414
with vias 416 to form a sandwich capable of carrying more current
than one trace 412 alone. Pad strap 416 connects from a bonding pad
(not shown) to the inner trace 402 and is similarly constructed.
The strap 416 comprises a lower trace 418 and vias 420 to form a
sandwich.
[0038] The mesh connection 422 is connected to the inner ring 404
through via 424. The mesh connection 426 is connected to the outer
ring 402 and the inner ring 408 through via 428.
[0039] The present illustration is schematic in nature, but was
chosen to best illustrate the connections of the various elements.
In practice, the physical shape and proximity of the components may
be substantially different while maintaining within the spirit and
intent of the present invention.
[0040] The foregoing description of the invention has been
presented for purposes of illustration and description. It is not
intended to be exhaustive or to limit the invention to the precise
form disclosed, and other modifications and variations may be
possible in light of the above teachings. The embodiment was chosen
and described in order to best explain the principles of the
invention and its practical application to thereby enable others
skilled in the art to best utilize the invention in various
embodiments and various modifications as are suited to the
particular use contemplated. It is intended that the appended
claims be construed to include other alternative embodiments of the
invention except insofar as limited by the prior art.
* * * * *