U.S. patent application number 13/774954 was filed with the patent office on 2013-07-04 for integrated circuit including gate electrode tracks that each form gate electrodes of different transistor types with intervening non-gate-forming gate electrode track.
The applicant listed for this patent is Scott T. Becker, Michael C. Smayling. Invention is credited to Scott T. Becker, Michael C. Smayling.
Application Number | 20130168778 13/774954 |
Document ID | / |
Family ID | 38475620 |
Filed Date | 2013-07-04 |
United States Patent
Application |
20130168778 |
Kind Code |
A1 |
Becker; Scott T. ; et
al. |
July 4, 2013 |
Integrated Circuit Including Gate Electrode Tracks That Each Form
Gate Electrodes of Different Transistor Types With Intervening
Non-Gate-Forming Gate Electrode Track
Abstract
A first gate electrode track includes a first gate electrode
feature forming a first n-channel transistor with a first
n-diffusion region and a second gate electrode feature forming a
first p-channel transistor with a first p-diffusion region. A
second gate electrode track includes a third gate electrode feature
forming a second n-channel transistor with a second n-diffusion
region and a fourth gate electrode feature forming a second
p-channel transistor with a second p-diffusion region. A third gate
electrode track is positioned between and parallel to the first and
second gate electrode tracks, such that no other gate electrode
track is positioned between the third gate electrode track and
either of the first or second gate electrode tracks. The third gate
electrode track is not interrupted between the first and second
gate electrode tracks. The third gate electrode track does not
include a gate electrode feature of any transistor.
Inventors: |
Becker; Scott T.; (Scotts
Valley, CA) ; Smayling; Michael C.; (Fremont,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Becker; Scott T.
Smayling; Michael C. |
Scotts Valley
Fremont |
CA
CA |
US
US |
|
|
Family ID: |
38475620 |
Appl. No.: |
13/774954 |
Filed: |
February 22, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12572225 |
Oct 1, 2009 |
8436400 |
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13774954 |
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12212562 |
Sep 17, 2008 |
7842975 |
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12572225 |
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11683402 |
Mar 7, 2007 |
7446352 |
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12212562 |
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60781288 |
Mar 9, 2006 |
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Current U.S.
Class: |
257/401 |
Current CPC
Class: |
H01L 21/28123 20130101;
H01L 23/5283 20130101; H01L 2027/11866 20130101; H01L 2027/11862
20130101; H01L 2027/11861 20130101; H01L 29/42372 20130101; H01L
2027/11875 20130101; H01L 2924/0002 20130101; H01L 23/5226
20130101; H01L 27/088 20130101; H01L 2027/11864 20130101; H01L
27/0207 20130101; H01L 27/11807 20130101; H01L 2027/11812 20130101;
G06F 30/39 20200101; H01L 2027/11855 20130101; H01L 27/092
20130101; H01L 2924/0002 20130101; H01L 2027/11814 20130101; H01L
2027/11887 20130101; G06F 30/392 20200101; H01L 21/823871 20130101;
H01L 29/42376 20130101; H01L 2027/11888 20130101; H01L 2924/00
20130101 |
Class at
Publication: |
257/401 |
International
Class: |
H01L 29/423 20060101
H01L029/423 |
Claims
1. An integrated circuit, comprising: a first gate electrode track
including a first gate electrode feature that forms a first
n-channel transistor as it crosses a first n-diffusion region and a
second gate electrode feature that forms a first p-channel
transistor as it crosses a first p-diffusion region; a second gate
electrode track including a third gate electrode feature that forms
a second n-channel transistor as it crosses a second n-diffusion
region and a fourth gate electrode feature that forms a second
p-channel transistor as it crosses a second p-diffusion region; and
a third gate electrode track positioned between and parallel to the
first and second gate electrode tracks such that no other gate
electrode track is positioned between the third gate electrode
track and either of the first or second gate electrode tracks,
wherein the third gate electrode track is not interrupted between
the first and second gate electrode tracks, and wherein the third
gate electrode track does not include a gate electrode feature of
any transistor.
Description
CLAIM OF PRIORITY
[0001] This application is a continuation application under 35
U.S.C. 120 of prior U.S. application Ser. No. 12/572,225, filed
Oct. 1, 2009, and entitled "Semiconductor Device with Gate Level
Including Gate Electrode Conductors for Transistors of First Type
and Transistors of Second Type with Some Gate Electrode Conductors
of Different Length" (As Amended), which is a continuation
application under 35 U.S.C. 120 of prior U.S. application Ser. No.
12/212,562, filed Sep. 17, 2008, entitled "Dynamic Array
Architecture," and issued as U.S. Pat. No. 7,842,975, which is a
continuation application under 35 U.S.C. 120 of prior U.S.
application Ser. No. 11/683,402, filed Mar. 7, 2007, entitled
"Dynamic Array Architecture," and issued as U.S. Pat. No.
7,446,352, which claims priority under 35 U.S.C. 119(e) to U.S.
Provisional Patent Application No. 60/781,288, filed Mar. 9, 2006.
Each of the above-identified applications is incorporated herein by
reference in its entirety.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This application is related to each application identified
in the table below. The disclosure of each application identified
in the table below is incorporated herein by reference in its
entirety.
TABLE-US-00001 Attorney Docket No. Application No. Filing Date
TELAP004AC2 12/561,207 Sep. 16, 2009 TELAP004AC3 12/561,216 Sep.
16, 2009 TELAP004AC4 12/561,220 Sep. 16, 2009 TELAP004AC5
12/561,224 Sep. 16, 2009 TELAP004AC6 12/561,229 Sep. 16, 2009
TELAP004AC7 12/561,234 Sep. 16, 2009 TELAP004AC8 12/561,238 Sep.
16, 2009 TELAP004AC9 12/561,243 Sep. 16, 2009 TELAP004AC10
12/561,246 Sep. 16, 2009 TELAP004AC11 12/561,247 Sep. 16, 2009
TELAP004AC12 12/563,031 Sep. 18, 2009 TELAP004AC13 12/563,042 Sep.
18, 2009 TELAP004AC14 12/563,051 Sep. 18, 2009 TELAP004AC15
12/563,056 Sep. 18, 2009 TELAP004AC16 12/563,061 Sep. 18, 2009
TELAP004AC17 12/563,063 Sep. 18, 2009 TELAP004AC18 12/563,066 Sep.
18, 2009 TELAP004AC19 12/563,074 Sep. 18, 2009 TELAP004AC20
12/563,076 Sep. 18, 2009 TELAP004AC21 12/563,077 Sep. 18, 2009
TELAP004AC22 12/567,528 Sep. 25, 2009 TELAP004AC23 12/567,542 Sep.
25, 2009 TELAP004AC24 12/567,555 Sep. 25, 2009 TELAP004AC25
12/567,565 Sep. 25, 2009 TELAP004AC26 12/567,574 Sep. 25, 2009
TELAP004AC27 12/567,586 Sep. 25, 2009 TELAP004AC28 12/567,597 Sep.
25, 2009 TELAP004AC29 12/567,602 Sep. 25, 2009 TELAP004AC30
12/567,609 Sep. 25, 2009 TELAP004AC31 12/567,616 Sep. 25, 2009
TELAP004AC32 12/567,623 Sep. 25, 2009 TELAP004AC33 12/567,630 Sep.
25, 2009 TELAP004AC34 12/567,634 Sep. 25, 2009 TELAP004AC35
12/567,641 Sep. 25, 2009 TELAP004AC36 12/567,648 Sep. 25, 2009
TELAP004AC37 12/567,654 Sep. 25, 2009 TELAP004AC38 12/571,343 Sep.
30, 2009 TELAP004AC39 12/571,351 Sep. 30, 2009 TELAP004AC40
12/571,357 Sep. 30, 2009 TELAP004AC41 12/571,998 Oct. 1, 2009
TELAP004AC42 12/572,011 Oct. 1, 2009 TELAP004AC43 12/572,022 Oct.
1, 2009 TELAP004AC44 12/572,046 Oct. 1, 2009 TELAP004AC45
12/572,055 Oct. 1, 2009 TELAP004AC46 12/572,061 Oct. 1, 2009
TELAP004AC47 12/572,068 Oct. 1, 2009 TELAP004AC48 12/572,077 Oct.
1, 2009 TELAP004AC49 12/572,091 Oct. 1, 2009 TELAP004AC50
12/572,194 Oct. 1, 2009 TELAP004AC51 12/572,201 Oct. 1, 2009
TELAP004AC52 12/572,212 Oct. 1, 2009 TELAP004AC53 12/572,218 Oct.
1, 2009 TELAP004AC54 12/572,221 Oct. 1, 2009 TELAP004AC55
12/572,225 Oct. 1, 2009 TELAP004AC56 12/572,228 Oct. 1, 2009
TELAP004AC57 12/572,229 Oct. 1, 2009 TELAP004AC58 12/572,232 Oct.
1, 2009 TELAP004AC59 12/572,237 Oct. 1, 2009 TELAP004AC60
12/572,239 Oct. 1, 2009 TELAP004AC61 12/572,243 Oct. 1, 2009
BECKP004B 12/013,342 Jan. 11, 2008 BECKP004B.C1 13/073,994 Mar. 28,
2011 BECKP004C 12/013,356 Jan. 11, 2008 BECKP004C.C1 13/047,474
Mar. 14, 2011 BECKP004D 12/013,366 Jan. 11, 2008 BECKP004D.C1
13/007,582 Jan. 14, 2011 BECKP004D.C2 13/007,584 Jan. 14, 2011
TELAP014 12/363,705 Jan. 30, 2009 TELAP015A 12/402,465 Mar. 11,
2009 TELAP015AC1 12/753,711 Apr. 2, 2010 TELAP015AC2 12/753,727
Apr. 2, 2010 TELAP015AC3 12/753,733 Apr. 2, 2010 TELAP015AC4
12/753,740 Apr. 2, 2010 TELAP015AC5 12/753,753 Apr. 2, 2010
TELAP015AC6 12/753,758 Apr. 2, 2010 TELAP015AC6A 13/741,298 Jan.
14, 2013 TELAP015AC7 12/753,766 Apr. 2, 2010 TELAP015AC7A
13/589,028 Aug. 17, 2012 TELAP015AC8 12/753,776 Apr. 2, 2010
TELAP015AC9 12/753,789 Apr. 2, 2010 TELAP015AC10 12/753,793 Apr. 2,
2010 TELAP015AC11 12/753,795 Apr. 2, 2010 TELAP015AC12 12/753,798
Apr. 2, 2010 TELAP015AC12A 13/741,305 Jan. 14, 2013 TELAP015AC13
12/753,805 Apr. 2, 2010 TELAP015AC14 12/753,810 Apr. 2, 2010
TELAP015AC15 12/753,817 Apr. 2, 2010 TELAP015AC16 12/754,050 Apr.
5, 2010 TELAP015AC17 12/754,061 Apr. 5, 2010 TELAP015AC18
12/754,078 Apr. 5, 2010 TELAP015AC19 12/754,091 Apr. 5, 2010
TELAP015AC20 12/754,103 Apr. 5, 2010 TELAP015AC21 12/754,114 Apr.
5, 2010 TELAP015AC22 12/754,129 Apr. 5, 2010 TELAP015AC23
12/754,147 Apr. 5, 2010 TELAP015AC24 12/754,168 Apr. 5, 2010
TELAP015AC25 12/754,215 Apr. 5, 2010 TELAP015AC26 12/754,233 Apr.
5, 2010 TELAP015AC27 12/754,351 Apr. 5, 2010 TELAP015AC27A
13/591,141 Aug. 21, 2012 TELAP015AC28 12/754,384 Apr. 5, 2010
TELAP015AC29 12/754,563 Apr. 5, 2010 TELAP015AC30 12/754,566 Apr.
5, 2010 TELAP016 12/399,948 Mar. 7, 2009 TELAP017 12/411,249 Mar.
25, 2009 TELAP017.D 13/085,447 Apr. 12, 2011 TELAP018 12/484,130
Jun. 12, 2009 TELAP019 12/479,674 Jun. 5, 2009 TELAP020 12/481,445
Jun. 9, 2009 TELAP021 12/497,052 Jul. 2, 2009 TELAP021C1 13/540,529
Jul. 2, 2012 TELAP022A 12/466,335 May 14, 2009 TELAP022B 12/466,341
May 14, 2009 TELAP023 12/512,932 Jul. 30, 2009 TELAP048 12/435,672
May 5, 2009 TELAP049 12/775,429 May 6, 2010 TELAP051 12/904,134
Oct. 13, 2010 TELAP053 13/373,470 Nov. 14, 2011 TELAP054 13/312,673
Dec. 6, 2011 TELAP055 13/473,439 May 16, 2012 TELAP056 13/740,191
Jan. 12, 2013
BACKGROUND
[0003] A push for higher performance and smaller die size drives
the semiconductor industry to reduce circuit chip area by
approximately 50% every two years. The chip area reduction provides
an economic benefit for migrating to newer technologies. The 50%
chip area reduction is achieved by reducing the feature sizes
between 25% and 30%. The reduction in feature size is enabled by
improvements in manufacturing equipment and materials. For example,
improvement in the lithographic process has enabled smaller feature
sizes to be achieved, while improvement in chemical mechanical
polishing (CMP) has in-part enabled a higher number of interconnect
layers.
[0004] In the evolution of lithography, as the minimum feature size
approached the wavelength of the light source used to expose the
feature shapes, unintended interactions occurred between
neighboring features. Today minimum feature sizes are approaching
45 nm (nanometers), while the wavelength of the light source used
in the photolithography process remains at 193 nm. The difference
between the minimum feature size and the wavelength of light used
in the photolithography process is defined as the lithographic gap.
As the lithographic gap grows, the resolution capability of the
lithographic process decreases.
[0005] An interference pattern occurs as each shape on the mask
interacts with the light. The interference patterns from
neighboring shapes can create constructive or destructive
interference. In the case of constructive interference, unwanted
shapes may be inadvertently created. In the case of destructive
interference, desired shapes may be inadvertently removed. In
either case, a particular shape is printed in a different manner
than intended, possibly causing a device failure. Correction
methodologies, such as optical proximity correction (OPC), attempt
to predict the impact from neighboring shapes and modify the mask
such that the printed shape is fabricated as desired. The quality
of the light interaction prediction is declining as process
geometries shrink and as the light interactions become more
complex.
[0006] In view of the foregoing, a solution is needed for managing
lithographic gap issues as technology continues to progress toward
smaller semiconductor device features sizes.
SUMMARY
[0007] In one embodiment, an integrated circuit is disclosed to
include a first gate electrode track, a second gate electrode
track, and a third gate electrode track. The first gate electrode
track includes a first gate electrode feature that forms a first
n-channel transistor as it crosses a first n-diffusion region and a
second gate electrode feature that forms a first p-channel
transistor as it crosses a first p-diffusion region. The second
gate electrode track includes a third gate electrode feature that
forms a second n-channel transistor as it crosses a second
n-diffusion region and a fourth gate electrode feature that forms a
second p-channel transistor as it crosses a second p-diffusion
region. The third gate electrode track is positioned between and
parallel to the first and second gate electrode tracks, such that
no other gate electrode track is positioned between the third gate
electrode track and either of the first or second gate electrode
tracks. The third gate electrode track is not interrupted between
the first and second gate electrode tracks. And, the third gate
electrode track does not include a gate electrode feature of any
transistor.
[0008] In another embodiment, a cell of a semiconductor device is
disclosed. The cell includes a substrate portion formed to include
a plurality of diffusion regions. The plurality of diffusion
regions respectively correspond to active areas of the substrate
portion within which one or more processes are applied to modify
one or more electrical characteristics of the active areas of the
substrate portion. The plurality of diffusion regions are separated
from each other by one or more non-active regions of the substrate
portion.
[0009] Also in this embodiment, the cell includes a gate electrode
level of the cell formed above the substrate portion. The gate
electrode level includes a number of conductive features defined to
extend in only a first parallel direction. Adjacent ones of the
number of conductive features that share a common line of extent in
the first parallel direction are fabricated from respective
originating layout features that are separated from each other by
an end-to-end spacing having a size measured in the first parallel
direction. The size of each end-to-end spacing between originating
layout features corresponding to adjacent ones of the number of
conductive features within the gate electrode level of the cell is
substantially equal and is minimized to an extent allowed by a
semiconductor device manufacturing capability. The number of
conductive features within the gate electrode level of the cell
includes conductive features defined along at least four different
virtual lines of extent in the first parallel direction across the
gate electrode level of the cell.
[0010] A width size of the conductive features within the gate
electrode level is measured perpendicular to the first parallel
direction. The width size of the conductive features within a
photolithographic interaction radius within the gate electrode
level is less than a wavelength of light used in a photolithography
process to fabricate the conductive features within the gate
electrode level. The wavelength of light used in the
photolithography process is less than or equal to 193 nanometers.
The photolithographic interaction radius is five wavelengths of
light used in the photolithography process.
[0011] Some of the number of conductive features within the gate
electrode level of the cell are defined to include one or more gate
electrode portions which extend over one or more of the active
areas of the substrate portion corresponding to the plurality of
diffusion regions. Each gate electrode portion and a corresponding
active area of the substrate portion over which it extends together
define a respective transistor device.
[0012] Also in this embodiment, the cell includes a number of
interconnect levels formed above the gate electrode level of the
cell. The substrate portion, the gate electrode level of the cell,
and the number of interconnect levels are spatially aligned such
that structures fabricated within each of the substrate portion,
the gate electrode level of the cell, and the number of
interconnect levels spatially relate to connect as required to form
functional electronic devices within the semiconductor device.
[0013] Other aspects and advantages of the invention will become
more apparent from the following detailed description, taken in
conjunction with the accompanying drawings, illustrating by way of
example the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is an illustration showing a number of neighboring
layout features and a representation of light intensity used to
render each of the layout features, in accordance with one
embodiment of the present invention;
[0015] FIG. 2 is an illustration showing a generalized stack of
layers used to define a dynamic array architecture, in accordance
with one embodiment of the present invention;
[0016] FIG. 3A is an illustration showing an exemplary base grid to
be projected onto the dynamic array to facilitate definition of the
restricted topology, in accordance with one embodiment of the
present invention;
[0017] FIG. 3B is an illustration showing separate base grids
projected across separate regions of the die, in accordance with an
exemplary embodiment of the present invention;
[0018] FIG. 3C is an illustration showing an exemplary
linear-shaped feature defined to be compatible with the dynamic
array, in accordance with one embodiment of the present
invention;
[0019] FIG. 3D is an illustration showing another exemplary
linear-shaped feature defined to be compatible with the dynamic
array, in accordance with one embodiment of the present
invention;
[0020] FIG. 4 is an illustration showing a diffusion layer layout
of an exemplary dynamic array, in accordance with one embodiment of
the present invention;
[0021] FIG. 5 is an illustration showing a gate electrode layer and
a diffusion contact layer above and adjacent to the diffusion layer
of FIG. 4, in accordance with one embodiment of the present
invention;
[0022] FIG. 6 is an illustration showing a gate electrode contact
layer defined above and adjacent to the gate electrode layer of
FIG. 5, in accordance with one embodiment of the present
invention;
[0023] FIG. 7A is an illustration showing a traditional approach
for making contact to the gate electrode;
[0024] FIG. 7B is an illustration showing a gate electrode contact
defined in accordance with one embodiment of the present
invention;
[0025] FIG. 8A is an illustration showing a metal 1 layer defined
above and adjacent to the gate electrode contact layer of FIG. 6,
in accordance with one embodiment of the present invention;
[0026] FIG. 8B is an illustration showing the metal 1 layer of FIG.
8A with larger track widths for the metal 1 ground and power
tracks, relative to the other metal 1 tracks;
[0027] FIG. 9 is an illustration showing a via 1 layer defined
above and adjacent to the metal 1 layer of FIG. 8A, in accordance
with one embodiment of the present invention;
[0028] FIG. 10 is an illustration showing a metal 2 layer defined
above and adjacent to the via 1 layer of FIG. 9, in accordance with
one embodiment of the present invention;
[0029] FIG. 11 is an illustration showing conductor tracks
traversing the dynamic array in a first diagonal direction relative
to the first and second reference directions (x) and (y), in
accordance with one embodiment of the present invention;
[0030] FIG. 12 is an illustration showing conductor tracks
traversing the dynamic array in a second diagonal direction
relative to the first and second reference directions (x) and (y),
in accordance with one embodiment of the present invention;
[0031] FIG. 13A is an illustration showing an example of a
sub-resolution contact layout used to lithographically reinforce
diffusion contacts and gate electrode contacts, in accordance with
one embodiment of the present invention;
[0032] FIG. 13B is an illustration showing the sub-resolution
contact layout of FIG. 13A with sub-resolution contacts defined to
fill the grid to the extent possible, in accordance with one
embodiment of the present invention;
[0033] FIG. 13C is an illustration showing an example of a
sub-resolution contact layout utilizing various shaped
sub-resolution contacts, in accordance with one embodiment of the
present invention;
[0034] FIG. 13D is an illustration showing an exemplary
implementation of alternate phase shift masking (APSM) with
sub-resolution contacts, in accordance with one embodiment of the
present invention; and
[0035] FIG. 14 is an illustration showing a semiconductor chip
structure, in accordance with one embodiment of the present
invention.
[0036] FIG. 15 shows an example layout architecture defined in
accordance with one embodiment of the present invention.
DETAILED DESCRIPTION
[0037] In the following description, numerous specific details are
set forth in order to provide a thorough understanding of the
present invention. It will be apparent, however, to one skilled in
the art that the present invention may be practiced without some or
all of these specific details. In other instances, well known
process operations have not been described in detail in order not
to unnecessarily obscure the present invention.
[0038] Generally speaking, a dynamic array architecture is provided
to address semiconductor manufacturing process variability
associated with a continually increasing lithographic gap. In the
area of semiconductor manufacturing, lithographic gap is defined as
the difference between the minimum size of a feature to be defined
and the wavelength of light used to render the feature in the
lithographic process, wherein the feature size is less than the
wavelength of the light. Current lithographic processes utilize a
light wavelength of 193 nm. However, current feature sizes are as
small as 65 nm and are expected to soon approach sizes as small as
45 nm. With a size of 65 nm, the shapes are three times smaller
than the wavelength of the light used to define the shapes. Also,
considering that the interaction radius of light is about five
light wavelengths, it should be appreciated that shapes exposed
with a 193 nm light source will influence the exposure of shapes
approximately 5*193 nm (965 nm) away. When considering the 65 nm
sized features with respect to 90 nm sized features, it should be
appreciated that approximately two times as many 65 nm sizes
features may be within the 965 nm interaction radius of the 193 nm
light source as compared to the 90 nm sized features.
[0039] Due to the increased number of features within the
interaction radius of the light source, the extent and complexity
of light interference contributing to exposure of a given feature
is significant. Additionally, the particular shapes associated with
the features within the interaction radius of the light source
weighs heavily on the type of light interactions that occur.
Traditionally, designers were allowed to define essentially any
two-dimensional topology of feature shapes so long as a set of
design rules were satisfied. For example, in a given layer of the
chip, i.e., in a given mask, the designer may have defined
two-dimensionally varying features having bends that wrap around
each other. When such two-dimensionally varying features are
located in neighboring proximity to each other, the light used to
expose the features will interact in a complex and generally
unpredictable manner. The light interaction becomes increasingly
more complex and unpredictable as the feature sizes and relative
spacing become smaller.
[0040] Traditionally, if a designer follows the established set of
design rules, the resulting product will be manufacturable with a
specified probability associated with the set of design rules.
Otherwise, for a design that violates the set of design rules, the
probability of successful manufacture of the resulting product is
unknown. To address the complex light interaction between
neighboring two-dimensionally varying features, in the interest of
successful product manufacturing, the set of design rules is
expanded significantly to adequately address the possible
combinations of two-dimensionally varying features. This expanded
set of design rules quickly becomes so complicated and unwieldy
that application of the expanded set of design rules becomes
prohibitively time consuming, expensive, and prone to error. For
example, the expanded set of design rules requires complex
verification. Also, the expanded set of design rules may not be
universally applied. Furthermore, manufacturing yield is not
guaranteed even if all design rules are satisfied.
[0041] It should be appreciated that accurate prediction of all
possible light interactions when rendering arbitrarily-shaped
two-dimensional features is generally not feasible. Moreover, as an
alternative to or in combination with expansion of the set of
design rules, the set of design rules may also be modified to
include increased margin to account for unpredictable light
interaction between the neighboring two-dimensionally varying
features. Because the design rules are established in an attempt to
cover the random two-dimensional feature topology, the design rules
may incorporate a significant amount of margin. While addition of
margin in the set of design rules assists with the layout portions
that include the neighboring two-dimensionally varying features,
such global addition of margin causes other portions of the layout
that do not include the neighboring two-dimensionally varying
features to be overdesigned, thus leading to decreased optimization
of chip area utilization and electrical performance.
[0042] In view of the foregoing, it should be appreciated that
semiconductor product yield is reduced as a result of parametric
failures that stem from variability introduced by design-dependent
unconstrained feature topologies, i.e., arbitrary two-dimensionally
varying features disposed in proximity to each other. By way of
example, these parametric failures may result from failure to
accurately print contacts and vias and from variability in
fabrication processes. The variability in fabrication processes may
include CMP dishing, layout feature shape distortion due to
photolithography, gate distortion, oxide thickness variability,
implant variability, and other fabrication related phenomena. The
dynamic array architecture of the present invention is defined to
address the above-mentioned semiconductor manufacturing process
variability.
[0043] FIG. 1 is an illustration showing a number of neighboring
layout features and a representation of light intensity used to
render each of the layout features, in accordance with one
embodiment of the present invention. Specifically, three
neighboring linear-shaped layout features (101A-101C) are depicted
as being disposed in a substantially parallel relationship within a
given mask layer. The distribution of light intensity from a layout
feature shape is represented by a sine function. The sine functions
(103A-103C) represent the distribution of light intensity from each
of the layout features (101A-101C, respectively). The neighboring
linear-shaped layout features (101A-101C) are spaced apart at
locations corresponding to peaks of the sine functions (103A-103C).
Thus, constructive interference between the light energy associated
with the neighboring layout features (101A-101C), i.e., at the
peaks of the sinc functions (103A-103C), serves to reinforce the
exposure of the neighboring shapes (101A-101C) for the layout
feature spacing illustrated. In accordance with the foregoing, the
light interaction represented in FIG. 1 represents a synchronous
case.
[0044] As illustrated in FIG. 1, when linear-shaped layout features
are defined in a regular repeating pattern at an appropriate
spacing, constructive interference of the light energy associated
with the various layout features serves to enhance the exposure of
each layout feature. The enhanced exposure of the layout features
provided by the constructive light interference can dramatically
reduce or even eliminate a need to utilize optical proximity
correction (OPC) and/or reticle enhancement technology (RET) to
obtain sufficient rendering of the layout features.
[0045] A forbidden pitch, i.e., forbidden layout feature spacing,
occurs when the neighboring layout features (101A-101C) are spaced
such that peaks of the sine function associated with one layout
feature align with valleys of the sine function associated with
another layout feature, thus causing destructive interference of
the light energy. The destructive interference of the light energy
causes the light energy focused at a given location to be reduced.
Therefore, to realize the beneficial constructive light
interference associated with neighboring layout features, it is
necessary to predict the layout feature spacing at which the
constructive overlap of the sine function peaks will occur.
Predictable constructive overlap of the sine function peaks and
corresponding layout feature shape enhancement can be realized if
the layout feature shapes are rectangular, near the same size, and
are oriented in the same direction, as illustrated by the layout
features (101A-101C) in FIG. 1. In this manner, resonant light
energy from neighboring layout feature shapes is used to enhance
the exposure of a particular layout feature shape.
[0046] FIG. 2 is an illustration showing a generalized stack of
layers used to define a dynamic array architecture, in accordance
with one embodiment of the present invention. It should be
appreciated that the generalized stack of layers used to define the
dynamic array architecture, as described with respect to FIG. 2, is
not intended to represent an exhaustive description of the CMOS
manufacturing process. However, the dynamic array is to be built in
accordance with standard CMOS manufacturing processes. Generally
speaking, the dynamic array architecture includes both the
definition of the underlying structure of the dynamic array and the
techniques for assembling the dynamic array for optimization of
area utilization and manufacturability. Thus, the dynamic array is
designed to optimize semiconductor manufacturing capabilities.
[0047] With regard to the definition of the underlying structure of
the dynamic array, the dynamic array is built-up in a layered
manner upon a base substrate 201, e.g., upon a silicon substrate,
or silicon-on-insulator (SOI) substrate. Diffusion regions 203 are
defined in the base substrate 201. The diffusion regions 203
represent selected regions of the base substrate 201 within which
impurities are introduced for the purpose of modifying the
electrical properties of the base substrate 201. Above the
diffusion regions 203, diffusion contacts 205 are defined to enable
connection between the diffusion regions 203 and conductor lines.
For example, the diffusion contacts 205 are defined to enable
connection between source and drain diffusion regions 203 and their
respective conductor nets. Also, gate electrode features 207 are
defined above the diffusion regions 203 to form transistor gates.
Gate electrode contacts 209 are defined to enable connection
between the gate electrode features 207 and conductor lines. For
example, the gate electrode contacts 209 are defined to enable
connection between transistor gates and their respective conductor
nets.
[0048] Interconnect layers are defined above the diffusion contact
205 layer and the gate electrode contact layer 209. The
interconnect layers include a first metal (metal 1) layer 211, a
first via (via 1) layer 213, a second metal (metal 2) layer 215, a
second via (via 2) layer 217, a third metal (metal 3) layer 219, a
third via (via 3) layer 221, and a fourth metal (metal 4) layer
223. The metal and via layers enable definition of the desired
circuit connectivity. For example, the metal and via layers enable
electrical connection of the various diffusion contacts 205 and
gate electrode contacts 209 such that the logic function of the
circuitry is realized. It should be appreciated that the dynamic
array architecture is not limited to a specific number of
interconnect layers, i.e., metal and via layers. In one embodiment,
the dynamic array may include additional interconnect layers 225,
beyond the fourth metal (metal 4) layer 223. Alternatively, in
another embodiment, the dynamic array may include less than four
metal layers.
[0049] The dynamic array is defined such that layers (other than
the diffusion region layer 203) are restricted with regard to
layout feature shapes that can be defined therein. Specifically, in
each layer other than the diffusion region layer 203, only
linear-shaped layout features are allowed. A linear-shaped layout
feature in a given layer is characterized as having a consistent
vertical cross-section shape and extending in a single direction
over the substrate. Thus, the linear-shaped layout features define
structures that are one-dimensionally varying. The diffusion
regions 203 are not required to be one-dimensionally varying,
although they are allowed to be if necessary. Specifically, the
diffusion regions 203 within the substrate can be defined to have
any two-dimensionally varying shape with respect to a plane
coincident with a top surface of the substrate. In one embodiment,
the number of diffusion bend topologies is limited such that the
interaction between the bend in diffusion and the conductive
material, e.g., polysilicon, that forms the gate electrode of the
transistor is predictable and can be accurately modeled. The
linear-shaped layout features in a given layer are positioned to be
parallel with respect to each other. Thus, the linear-shaped layout
features in a given layer extend in a common direction over the
substrate and parallel with the substrate.
[0050] The underlying layout methodology of the dynamic array uses
constructive light interference of light waves in the lithographic
process to reinforce exposure of neighboring shapes in a given
layer. Therefore, the spacing of the parallel, linear-shaped layout
features in a given layer is designed around the constructive light
interference of the standing light waves such that lithographic
correction (e.g., OPC/RET) is minimized or eliminated. Thus, in
contrast to conventional OPC/RET-based lithographic processes, the
dynamic array defined herein exploits the light interaction between
neighboring features, rather than attempting to compensate for the
light interaction between neighboring features.
[0051] Because the standing light wave for a given linear-shaped
layout feature can be accurately modeled, it is possible to predict
how the standing light waves associated with the neighboring
linear-shaped layout features disposed in parallel in a given layer
will interact. Therefore, it is possible to predict how the
standing light wave used to expose one linear-shaped feature will
contribute to the exposure of its neighboring linear-shaped
features. Prediction of the light interaction between neighboring
linear-shaped features enables the identification of an optimum
feature-to-feature spacing such that light used to render a given
shape will reinforce its neighboring shapes. The feature-to-feature
spacing in a given layer is defined as the feature pitch, wherein
the pitch is the center-to-center separation distance between
adjacent linear-shaped features in a given layer.
[0052] To provide the desired exposure reinforcement between
neighboring features, the linear-shaped layout features in a given
layer are spaced such that constructive and destructive
interference of the light from neighboring features will be
optimized to produce the best rendering of all features in the
neighborhood. The feature-to-feature spacing in a given layer is
proportional to the wavelength of the light used to expose the
features. The light used to expose each feature within about a five
light wavelength distance from a given feature will serve to
enhance the exposure of the given feature to some extent. The
exploitation of constructive interference of the standing light
waves used to expose neighboring features enables the manufacturing
equipment capability to be maximized and not be limited by concerns
regarding light interactions during the lithography process.
[0053] As discussed above, the dynamic array incorporates a
restricted topology in which the features within each layer (other
than diffusion) are required to be linear-shaped features that are
oriented in a parallel manner to traverse over the substrate in a
common direction. With the restricted topology of the dynamic
array, the light interaction in the photolithography process can be
optimized such that the printed image on the mask is essentially
identical to the drawn shape in the layout, i.e., essentially a
100% accurate transfer of the layout onto the resist is
achieved.
[0054] FIG. 3A is an illustration showing an exemplary base grid to
be projected onto the dynamic array to facilitate definition of the
restricted topology, in accordance with one embodiment of the
present invention. The base grid can be used to facilitate parallel
placement of the linear-shaped features in each layer of the
dynamic array at the appropriate optimized pitch. Although not
physically defined as part of the dynamic array, the base grid can
be considered as a projection on each layer of the dynamic array.
Also, it should be understood that the base grid is projected in a
substantially consistent manner with respect to position on each
layer of the dynamic array, thus facilitating accurate feature
stacking and alignment.
[0055] In the exemplary embodiment of FIG. 3A, the base grid is
defined as a rectangular grid, i.e., Cartesian grid, in accordance
with a first reference direction (x) and a second reference
direction (y). The gridpoint-to-gridpoint spacing in the first and
second reference directions can be defined as necessary to enable
definition of the linear-shaped features at the optimized
feature-to-feature spacing. Also, the gridpoint spacing in the
first reference direction (x) can be different than the gridpoint
spacing in the second reference direction (y). In one embodiment, a
single base grid is projected across the entire die to enable
location of the various linear-shaped features in each layer across
the entire die. However, in other embodiments, separate base grids
can be projected across separate regions of the die to support
different feature-to-feature spacing requirements within the
separate regions of the die. FIG. 3B is an illustration showing
separate base grids projected across separate regions of the die,
in accordance with an exemplary embodiment of the present
invention.
[0056] The base grid is defined with consideration for the light
interaction function, i.e., the sine function, and the
manufacturing capability, wherein the manufacturing capability is
defined by the manufacturing equipment and processes to be utilized
in fabricating the dynamic array. With regard to the light
interaction function, the base grid is defined such that the
spacing between gridpoints enables alignment of peaks in the sine
functions describing the light energy projected upon neighboring
gridpoints. Therefore, linear-shaped features optimized for
lithographic reinforcement can be specified by drawing a line from
a first gridpoint to a second gridpoint, wherein the line
represents a rectangular structure of a given width. It should be
appreciated that the various linear-shaped features in each layer
can be specified according to their endpoint locations on the base
grid and their width.
[0057] FIG. 3C is an illustration showing an exemplary
linear-shaped feature 301 defined to be compatible with the dynamic
array, in accordance with one embodiment of the present invention.
The linear-shaped feature 301 has a substantially rectangular
cross-section defined by a width 303 and a height 307. The
linear-shaped feature 301 extends in a linear direction to a length
305. In one embodiment, a cross-section of the linear-shaped
feature, as defined by its width 303 and height 307, is
substantially uniform along its length 305. It should be
understood, however, that lithographic effects may cause a rounding
of the ends of the linear-shaped feature 301. The first and second
reference directions (x) and (y), respectively, of FIG. 3A are
shown to illustrate an exemplary orientation of the linear-shaped
feature on the dynamic array. It should be appreciated that the
linear-shaped feature may be oriented to have its length 305 extend
in either the first reference direction (x), the second reference
direction (y), or in diagonal direction defined relative to the
first and second reference directions (x) and (y). Regardless of
the linear-shaped features' particular orientation with respect to
the first and second reference directions (x) and (y), it should be
understood that the linear-shaped feature is defined in a plane
that is substantially parallel to a top surface of the substrate
upon which the dynamic array is built. Also, it should be
understood that the linear-shaped feature is free of bends, i.e.,
change in direction, in the plane defined by the first and second
reference directions.
[0058] FIG. 3D is an illustration showing another exemplary
linear-shaped feature 317 defined to be compatible with the dynamic
array, in accordance with one embodiment of the present invention.
The linear-shaped feature 317 has a trapezoidal cross-section
defined by a lower width 313, an upper width 315, and a height 309.
The linear-shaped feature 317 extends in a linear direction to a
length 311. In one embodiment, the cross-section of the
linear-shaped feature 317 is substantially uniform along its length
311. It should be understood, however, that lithographic effects
may cause a rounding of the ends of the linear-shaped feature 317.
The first and second reference directions (x) and (y),
respectively, of FIG. 3A are shown to illustrate an exemplary
orientation of the linear-shaped feature on the dynamic array. It
should be appreciated that the linear-shaped feature 317 may be
oriented to have its length 311 extend in either the first
reference direction (x), the second reference direction (y), or in
diagonal direction defined relative to the first and second
reference directions (x) and (y). Regardless of the particular
orientation of the linear-shaped feature 317 with regard to the
first and second reference directions (x) and (y), it should be
understood that the linear-shaped feature 317 is defined in a plane
that is substantially parallel to a top surface of the substrate
upon which the dynamic array is built. Also, it should be
understood that the linear-shaped feature 317 is free of bends,
i.e., change in direction, in the plane defined by the first and
second reference directions.
[0059] Although FIGS. 3C and 3D explicitly discuss linear shaped
features having rectangular and trapezoidal cross-sections,
respectively, it should be understood that the linear shaped
features having other types of cross-sections can be defined within
the dynamic array. Therefore, essentially any suitable
cross-sectional shape of the linear-shaped feature can be utilized
so long as the linear-shaped feature is defined to have a length
that extends in one direction, and is oriented to have its length
extend in either the first reference direction (x), the second
reference direction (y), or in diagonal direction defined relative
to the first and second reference directions (x) and (y).
[0060] The layout architecture of the dynamic array follows the
base grid pattern. Thus, it is possible to use grid points to
represent where changes in direction occur in diffusion, wherein
gate electrode and metal linear-shaped features are placed, where
contacts are placed, where opens are in the linear-shaped gate
electrode and metal features, etc. The pitch of the gridpoints,
i.e., the gridpoint-to-gridpoint spacing, should be set for a given
feature line width, e.g., width 303 in FIG. 3C, such that exposure
of neighboring linear-shaped features of the given feature line
width will reinforce each other, wherein the linear-shaped features
are centered on gridpoints. With reference to the dynamic array
stack of FIG. 2 and the exemplary base grid of FIG. 3A, in one
embodiment, the gridpoint spacing in the first reference direction
(x) is set by the required gate electrode gate pitch. In this same
embodiment, the gridpoint pitch in the second reference direction
(y) is set by the metal 1 and metal 3 pitch. For example, in a 90
nm process technology, i.e., minimum feature size equal to 90 nm,
the gridpoint pitch in the second reference direction (y) is about
0.24 micron. In one embodiment, metal 1 and metal 2 layers will
have a common spacing and pitch. A different spacing and pitch may
be used above the metal 2 layer.
[0061] The various layers of the dynamic array are defined such
that the linear-shaped features in adjacent layers extend in a
crosswise manner with respect to each other. For example, the
linear-shaped features of adjacent layers may extend orthogonally,
i.e., perpendicularly with respect to each other. Also, the
linear-shaped features of one layer may extend across the
linear-shaped features of an adjacent layer at an angle, e.g., at
about 45 degrees. For example, in one embodiment the linear-shaped
feature of one layer extend in the first reference direction (x)
and the linear-shaped features of the adjacent layer extend
diagonally with respect to the first (x) and second (y) reference
directions. It should be appreciated that to route a design in the
dynamic array having the linear-shaped features positioned in the
crosswise manner in adjacent layers, opens can be defined in the
linear-shaped features, and contacts and vias can be defined as
necessary.
[0062] The dynamic array minimizes the use of bends in layout
shapes to eliminate unpredictable lithographic interactions.
Specifically, prior to OPC or other RET processing, the dynamic
array allows bends in the diffusion layer to enable control of
device sizes, but does not allow bends in layers above the
diffusion layer. The layout features in each layer above the
diffusion layer are linear in shape, e.g., FIG. 3C, and disposed in
a parallel relationship with respect to each other. The linear
shapes and parallel positioning of layout features are implemented
in each stack layer of the dynamic array where predictability of
constructive light interference is necessary to ensure
manufacturability. In one embodiment, the linear shapes and
parallel positioning of layout features are implemented in the
dynamic array in each layer above diffusion through metal 2. Above
metal 2, the layout features may be of sufficient size and shape
that constructive light interference is not required to ensure
manufacturability. However, the presence of constructive light
interference in patterning layout features above metal 2 may be
beneficial.
[0063] An exemplary buildup of dynamic array layers from diffusion
through metal 2 are described with respect to FIGS. 4 through 14.
It should be appreciated that the dynamic array described with
respect to FIGS. 4 through 14 is provided by way of example only,
and is not intended to convey limitations of the dynamic array
architecture. The dynamic array can be used in accordance with the
principles presented herein to define essentially any integrated
circuit design.
[0064] FIG. 4 is an illustration showing a diffusion layer layout
of an exemplary dynamic array, in accordance with one embodiment of
the present invention. The diffusion layer of FIG. 4 shows a
p-diffusion region 401 and an n-diffusion region 403. While the
diffusion regions are defined according to the underlying base
grid, the diffusion regions are not subject to the linear-shaped
feature restrictions associated with the layers above the diffusion
layer. The diffusion regions 401 and 403 include diffusion squares
405 defined where diffusion contacts will be located. The diffusion
regions 401 and 403 do not include extraneous jogs or corners, thus
improving the use of lithographic resolution and enabling more
accurate device extraction. Additionally, n+ mask regions (412 and
416) and p+ mask regions (410 and 414) are defined as rectangles on
the (x), (y) grid with no extraneous jogs or notches. This style
permits use of larger diffusion regions, eliminates need for
OPC/RET, and enables use of lower resolution and lower cost
lithographic systems, e.g., i-line illumination at 365 nm. It
should be appreciated that the n+ mask region 416 and the p+ mask
region 410, as depicted in FIG. 4, are for an embodiment that does
not employ well-biasing. In an alternative embodiment where
well-biasing is to be used, the n+ mask region 416 shown in FIG. 4
will actually be defined as a p+ mask region. Also, in this
alternative embodiment, the p+ mask region 410 shown in FIG. 4 will
actually be defined as a n+ mask region.
[0065] FIG. 5 is an illustration showing a gate electrode layer and
a diffusion contact layer above and adjacent to the diffusion layer
of FIG. 4, in accordance with one embodiment of the present
invention. As those skilled in the CMOS arts will appreciate, the
gate electrode features 501 define the transistor gates. The gate
electrode features 501 are defined as linear shaped features
extending in a parallel relationship across the dynamic array in
the second reference direction (y). In one embodiment, the gate
electrode features 501 are defined to have a common width. However,
in another embodiment, one or more of the gate electrode features
can be defined to have a different width. For example, FIG. 5 shows
a gate electrode features 501A that has a larger width relative to
the other gate electrode features 501. The pitch (center-to-center
spacing) of the gate electrode features 501 is minimized while
ensuring optimization of lithographic reinforcement, i.e., resonant
imaging, provided by neighboring gate electrode features 501. For
discussion purposes, gate electrode features 501 extending across
the dynamic array in a given line are referred to as a gate
electrode track.
[0066] The gate electrode features 501 form n-channel and p-channel
transistors as they cross the diffusion regions 403 and 401,
respectively. Optimal gate electrode feature 501 printing is
achieved by drawing gate electrode features 501 at every grid
location, even though no diffusion region may be present at some
grid locations. Also, long continuous gate electrode features 501
tend to improve line end shortening effects at the ends of gate
electrode features within the interior of the dynamic array.
Additionally, gate electrode printing is significantly improved
when all bends are removed from the gate electrode features
501.
[0067] Each of the gate electrode tracks may be interrupted, i.e.,
broken, any number of times in linearly traversing across the
dynamic array in order to provide required electrical connectivity
for a particular logic function to be implemented. When a given
gate electrode track is required to be interrupted, the separation
between ends of the gate electrode track segments at the point of
interruption is minimized to the extent possible taking into
consideration the manufacturing capability and electrical effects.
In one embodiment, optimal manufacturability is achieved when a
common end-to-end spacing is used between features within a
particular layer.
[0068] Minimizing the separation between ends of the gate electrode
track segments at the points of interruption serves to maximize the
lithographic reinforcement, and uniformity thereof, provided from
neighboring gate electrode tracks. Also, in one embodiment, if
adjacent gate electrode tracks need to be interrupted, the
interruptions of the adjacent gate electrode tracks are made such
that the respective points of interruption are offset from each
other so as to avoid, to the extent possible, an occurrence of
neighboring points of interruption. More specifically, points of
interruption within adjacent gate electrode tracks are respectively
positioned such that a line of sight does not exist through the
points of interruption, wherein the line of sight is considered to
extend perpendicularly to the direction in which the gate electrode
tracks extend over the substrate. Additionally, in one embodiment,
the gate electrodes may extend through the boundaries at the top
and bottom of the cells, i.e., the PMOS or NMOS cells. This
embodiment would enable bridging of neighboring cells.
[0069] With further regard to FIG. 5, diffusion contacts 503 are
defined at each diffusion square 405 to enhance the printing of
diffusion contacts via resonant imaging. The diffusion squares 405
are present around every diffusion contact 503 to enhance the
printing of the power and ground connection polygons at the
diffusion contacts 503.
[0070] The gate electrode features 501 and diffusion contacts 503
share a common grid spacing. More specifically, the gate electrode
feature 501 placement is offset by one-half the grid spacing
relative to the diffusion contacts 503. For example, if the gate
electrode features 501 and diffusion contact 503 grid spacing is
0.36 .mu.m, then the diffusion contacts are placed such that the
x-coordinate of their center falls on an integer multiple of 0.36
.mu.m, while the x-coordinate of the center of each gate electrode
feature 501 minus 0.18 .mu.m should be an integer multiple of 0.36
.mu.m. In the present example, the x-coordinates are represented by
the following: [0071] Diffusion contact center x-coordinate=I*0.36
.mu.m, where I is the grid number; [0072] Gate electrode feature
center x-coordinate=0.18 .mu.m+I*0.36 .mu.m, where I is the grid
number.
[0073] The grid based system of the dynamic array ensures that all
contacts (diffusion and gate electrode) will land on a horizontal
grid that is equal to a multiple of one-half of the diffusion
contact grid and a vertical grid that is set by the metal 1 pitch.
In the example above, the gate electrode feature and diffusion
contact grid is 0.36 .mu.m. The diffusion contacts and gate
electrode contacts will land on a horizontal grid that is a
multiple of 0.18 .mu.m. Also, the vertical grid for 90 nm process
technologies is about 0.24 .mu.m.
[0074] FIG. 6 is an illustration showing a gate electrode contact
layer defined above and adjacent to the gate electrode layer of
FIG. 5, in accordance with one embodiment of the present invention.
In the gate electrode contact layer, gate electrode contacts 601
are drawn to enable connection of the gate electrode features 501
to the overlying metal conduction lines. In general, design rules
will dictate the optimum placement of the gate electrode contacts
601. In one embodiment, the gate electrode contacts are drawn on
top of the transistor endcap regions. This embodiment minimizes
white space in the dynamic array when design rules specify long
transistor endcaps. In some process technologies white space may be
minimized by placing a number of gate electrode contacts for a cell
in the center of the cell. Also, it should be appreciated that in
the present invention, the gate electrode contact 601 is oversized
in the direction perpendicular to the gate electrode feature 501 to
ensure overlap between the gate electrode contact 601 and the gate
electrode feature 501.
[0075] FIG. 7A is an illustration showing a traditional approach
for making contact to a gate electrode, e.g., polysilicon feature.
In the traditional configuration of FIG. 7A, an enlarged
rectangular gate electrode region 707 is defined where a gate
electrode contact 709 is to be located. The enlarged rectangular
gate electrode region 707 introduces a bend of distance 705 in the
gate electrode. The bend associated with the enlarged rectangular
gate electrode region 707 sets up undesirable light interactions
and distorts the gate electrode line 711. Distortion of the gate
electrode line 711 is especially problematic when the gate
electrode width is about the same as a transistor length.
[0076] FIG. 7B is an illustration showing a gate electrode contact
601, e.g., polysilicon contact, defined in accordance with one
embodiment of the present invention. The gate electrode contact 601
is drawn to overlap the edges of the gate electrode feature 501,
and extend in a direction substantially perpendicular to the gate
electrode feature 501. In one embodiment, the gate electrode
contact 601 is drawn such that the vertical dimension 703 is same
as the vertical dimension used for the diffusion contacts 503. For
example, if the diffusion contact 503 opening is specified to be
0.12 .mu.m square then the vertical dimension of the gate electrode
contact 601 is drawn at 0.12 .mu.m. However, in other embodiments,
the gate electrode contact 601 can be drawn such that the vertical
dimension 703 is different from the vertical dimension used for the
diffusion contacts 503.
[0077] In one embodiment, the gate electrode contact 601 extension
701 beyond the gate electrode feature 501 is set such that maximum
overlap is achieved between the gate electrode contact 601 and the
gate electrode feature 501. The extension 701 is defined to
accommodate line end shortening of the gate electrode contact 601,
and misalignment between the gate electrode contact layer and gate
electrode feature layer. The length of the gate electrode contact
601 is defined to ensure maximum surface area contact between the
gate electrode contact 601 and the gate electrode feature 501,
wherein the maximum surface area contact is defined by the width of
the gate electrode feature 501.
[0078] FIG. 8A is an illustration showing a metal 1 layer defined
above the gate electrode contact layer of FIG. 6, in accordance
with one embodiment of the present invention. The metal 1 layer
includes a number of metal 1 tracks 801-821 defined to include
linear shaped features extending in a parallel relationship across
the dynamic array. The metal 1 tracks 801-821 extend in a direction
substantially perpendicular to the gate electrode features 501 in
the underlying gate electrode layer of FIG. 5. Thus, in the present
example, the metal 1 tracks 801-821 extend linearly across the
dynamic array in the first reference direction (x). The pitch
(center-to-center spacing) of the metal 1 tracks 801-821 is
minimized while ensuring optimization of lithographic
reinforcement, i.e., resonant imaging, provided by neighboring
metal 1 tracks 801-821. For example, in one embodiment, the metal 1
tracks 801-821 are centered on a vertical grid of about 0.24 .mu.m
for a 90 nm process technology.
[0079] Each of the metal 1 tracks 801-821 may be interrupted, i.e.,
broken, any number of times in linearly traversing across the
dynamic array in order to provide required electrical connectivity
for a particular logic function to be implemented. When a given
metal 1 track 801-821 is required to be interrupted, the separation
between ends of the metal 1 track segments at the point of
interruption is minimized to the extent possible taking into
consideration manufacturing capability and electrical effects.
Minimizing the separation between ends of the metal 1 track
segments at the points of interruption serves to maximize the
lithographic reinforcement, and uniformity thereof, provided from
neighboring metal 1 tracks. Also, in one embodiment, if adjacent
metal 1 tracks need to be interrupted, the interruptions of the
adjacent metal 1 tracks are made such that the respective points of
interruption are offset from each other so as to avoid, to the
extent possible, an occurrence of neighboring points of
interruption. More specifically, points of interruption within
adjacent metal 1 tracks are respectively positioned such that a
line of sight does not exist through the points of interruption,
wherein the line of sight is considered to extend perpendicularly
to the direction in which the metal 1 tracks extend over the
substrate.
[0080] In the example of FIG. 8A, the metal 1 track 801 is
connected to the ground supply, and the metal 1 track 821 is
connected to the power supply voltage. In the embodiment of FIG.
8A, the widths of the metal 1 tracks 801 and 821 are the same as
the other metal 1 tracks 803-819. However, in another embodiment,
the widths of metal 1 tracks 801 and 821 are larger than the widths
of the other metal 1 tracks 803-819. FIG. 8B is an illustration
showing the metal 1 layer of FIG. 8A with larger track widths for
the metal 1 ground and power tracks (801A and 821A), relative to
the other metal 1 tracks 803-819.
[0081] The metal 1 track pattern is optimally configured to
optimize the use of "white space" (space not occupied by
transistors). The example of FIG. 8A includes the two shared metal
1 power tracks 801 and 821, and nine metal 1 signal tracks 803-819.
Metal 1 tracks 803, 809, 811, and 819 are defined as gate electrode
contact tracks in order to minimize white space. Metal 1 tracks 805
and 807 are defined to connect to n-channel transistor source and
drains. Metal 1 tracks 813, 815, and 817 are defined to connect to
p-channel source and drains. Also, any of the nine metal 1 signal
tracks 803-819 can be used as a feed through if no connection is
required. For example, metal 1 tracks 813 and 815 are configured as
feed through connections.
[0082] FIG. 9 is an illustration showing a via 1 layer defined
above and adjacent to the metal 1 layer of FIG. 8A, in accordance
with one embodiment of the present invention. Vias 901 are defined
in the via 1 layer to enable connection of the metal 1 tracks
801-821 to higher level conduction lines.
[0083] FIG. 10 is an illustration showing a metal 2 layer defined
above and adjacent to the via 1 layer of FIG. 9, in accordance with
one embodiment of the present invention. The metal 2 layer includes
a number of metal 2 tracks 1001 defined as linear shaped features
extending in a parallel relationship across the dynamic array. The
metal 2 tracks 1001 extend in a direction substantially
perpendicular to the metal I tracks 801-821 in the underlying metal
1 layer of FIG. 8A, and in a direction substantially parallel to
the gate electrode tracks 501 in the underlying gate electrode
layer of FIG. 5. Thus, in the present example, the metal 2 tracks
1001 extend linearly across the dynamic array in the second
reference direction (y).
[0084] The pitch (center-to-center spacing) of the metal 2 tracks
1001 is minimized while ensuring optimization of lithographic
reinforcement, i.e., resonant imaging, provided by neighboring
metal 2 tracks. It should be appreciated that regularity can be
maintained on higher level interconnect layers in the same manner
as implemented in the gate electrode and metal 1 layers. In one
embodiment, the gate electrode feature 501 pitch and the metal 2
track pitch is the same. In another embodiment, the contacted gate
electrode pitch (e.g., polysilicon-to-polysilicon space with a
diffusion contact in between) is greater than the metal 2 track
pitch. In this embodiment, the metal 2 track pitch is optimally set
to be 2/3 or 3/4 of the contacted gate electrode pitch. Thus, in
this embodiment, the gate electrode track and metal 2 track align
at every two gate electrode track pitches and every three metal 2
track pitches. For example, in a 90 nm process technology, the
optimum contacted gate electrode track pitch is 0.36 .mu.m, and the
optimum metal 2 track pitch is 0.24 .mu.m. In another embodiment,
the gate electrode track and the metal 2 track align at every three
gate electrode pitches and every four metal 2 pitches. For example,
in a 90 nm process technology, the optimum contacted gate electrode
track pitch is 0.36 .mu.m, and the optimum metal 2 track pitch is
0.27 .mu.m.
[0085] Each of the metal 2 tracks 1001 may be interrupted, i.e.,
broken, any number of times in linearly traversing across the
dynamic array in order to provide required electrical connectivity
for a particular logic function to be implemented. When a given
metal 2 track 1001 is required to be interrupted, the separation
between ends of the metal 2 track segments at the point of
interruption is minimized to the extent possible taking into
consideration manufacturing and electrical effects. Minimizing the
separation between ends of the metal 2 track segments at the points
of interruption serves to maximize the lithographic reinforcement,
and uniformity thereof, provided from neighboring metal 2 tracks.
Also, in one embodiment, if adjacent metal 2 tracks need to be
interrupted, the interruptions of the adjacent metal 2 tracks are
made such that the respective points of interruption are offset
from each other so as to avoid, to the extent possible, an
occurrence of neighboring points of interruption. More
specifically, points of interruption within adjacent metal 2 tracks
are respectively positioned such that a line of sight does not
exist through the points of interruption, wherein the line of sight
is considered to extend perpendicularly to the direction in which
the metal 2 tracks extend over the substrate.
[0086] As discussed above, the conduction lines in a given metal
layer above the gate electrode layer may traverse the dynamic array
in a direction coincident with either the first reference direction
(x) or the second reference direction (y). It should be further
appreciated that the conduction lines in a given metal layer above
the gate electrode layer may traverse the dynamic array in a
diagonal direction relative to the first and second reference
directions (x) and (y). FIG. 11 is an illustration showing
conductor tracks 1101 traversing the dynamic array in a first
diagonal direction relative to the first and second reference
directions (x) and (y), in accordance with one embodiment of the
present invention. FIG. 12 is an illustration showing conductor
tracks 1201 traversing the dynamic array in a second diagonal
direction relative to the first and second reference directions (x)
and (y), in accordance with one embodiment of the present
invention.
[0087] As with the metal 1 and metal 2 tracks discussed above, the
diagonal traversing conductor tracks 1101 and 1201 of FIGS. 11 and
12 may be interrupted, i.e., broken, any number of times in
linearly traversing across the dynamic array in order to provide
required electrical connectivity for a particular logic function to
be implemented. When a given diagonal traversing conductor track is
required to be interrupted, the separation between ends of the
diagonal conductor track at the point of interruption is minimized
to the extent possible taking into consideration manufacturing and
electrical effects. Minimizing the separation between ends of the
diagonal conductor track at the points of interruption serves to
maximize the lithographic reinforcement, and uniformity thereof,
provided from neighboring diagonal conductor tracks.
[0088] An optimal layout density within the dynamic array is
achieved by implementing the following design rules:
[0089] at least two metal 1 tracks be provided across the n-channel
device area;
[0090] at least two metal 1 tracks be provided across the p-channel
device area;
[0091] at least two gate electrode tracks be provided for the
n-channel device; and
[0092] at least two gate electrode tracks be provided for the
p-channel device.
[0093] Contacts and vias are becoming the most difficult mask from
a lithographic point of view. This is because the contacts and vias
are getting smaller, more closely spaced, and are randomly
distributed. The spacing and density of the cuts (contact or vias)
makes it extremely difficult to reliably print the shapes. For
example, cut shapes may be printed improperly due to destructive
interference patterns from neighboring shapes or lack of energy on
lone shapes. If a cut is properly printed, the manufacturing yield
of the associated contact or via is extremely high. Sub-resolution
contacts can be provided to reinforce the exposure of the actual
contacts, so long as the sub-resolution contacts do not resolve.
Also, the sub-resolution contacts can be of any shape so long as
they are smaller than the resolution capability of the lithographic
process.
[0094] FIG. 13A is an illustration showing an example of a
sub-resolution contact layout used to lithographically reinforce
diffusion contacts and gate electrode contacts, in accordance with
one embodiment of the present invention. Sub-resolution contacts
1301 are drawn such that they are below the resolution of the
lithographic system and will not be printed. The function of the
sub-resolution contacts 1301 is to increase the light energy at the
desired contact locations, e.g., 503, 601, through resonant
imaging. In one embodiment, sub-resolution contacts 1301 are placed
on a grid such that both gate electrode contacts 601 and diffusion
contacts 503 are lithographically reinforced. For example,
sub-resolution contacts 1301 are placed on a grid that is equal to
one-half the diffusion contact 503 grid spacing to positively
impact both gate electrode contacts 601 and diffusion contacts 503.
In one embodiment, a vertical spacing of the sub-resolution
contacts 1301 follows the vertical spacing of the gate electrode
contacts 601 and diffusion contacts 503.
[0095] Grid location 1303 in FIG. 13A denotes a location between
adjacent gate electrode contacts 601. Depending upon the
lithographic parameters in the manufacturing process, it is
possible that a sub-resolution contact 1301 at this grid location
would create an undesirable bridge between the two adjacent gate
electrode contacts 601. If bridging is likely to occur, a
sub-resolution contact 1301 at location 1303 can be omitted.
Although FIG. 13A shows an embodiment where sub-resolution contacts
are placed adjacent to actual features to be resolved and not
elsewhere, it should be understood that another embodiment may
place a sub-resolution contact at each available grid location so
as to fill the grid.
[0096] FIG. 13B is an illustration showing the sub-resolution
contact layout of FIG. 13A with sub-resolution contacts defined to
fill the grid to the extent possible, in accordance with one
embodiment of the present invention. It should be appreciated that
while the embodiment of FIG. 13B fills the grid to the extent
possible with sub-resolution contacts, placement of sub-resolution
contacts is avoided at locations that would potentially cause
undesirable bridging between adjacent fully resolved features.
[0097] FIG. 13C is an illustration showing an example of a
sub-resolution contact layout utilizing various shaped
sub-resolution contacts, in accordance with one embodiment of the
present invention. Alternative sub-resolution contact shapes can be
utilized so long as the sub-resolution contacts are below the
resolution capability of the manufacturing process. FIG. 13C shows
the use of "X-shaped" sub-resolution contacts 1305 to focus light
energy at the corners of the adjacent contacts. In one embodiment,
the ends of the X-shaped sub-resolution contact 1305 are extended
to further enhance the deposition of light energy at the corners of
the adjacent contacts.
[0098] FIG. 13D is an illustration showing an exemplary
implementation of alternate phase shift masking (APSM) with
sub-resolution contacts, in accordance with one embodiment of the
present invention. As in FIG. 13A, sub-resolution contacts are
utilized to lithographically reinforce diffusion contacts 503 and
gate electrode contacts 601. APSM is used to improve resolution
when neighboring shapes create destructive interference patterns.
The APSM technique modifies the mask so that the phase of light
traveling through the mask on neighboring shapes is 180 degrees out
of phase. This phase shift serves to remove destructive
interference and allowing for greater contact density. By way of
example, contacts in FIG. 13D marked with a plus "+" sign represent
contacts exposed with light waves of a first phase while contacts
marked with a minus sign "-" represent contacts exposed with light
waves that are shifted in phase by 180 degrees relative to the
first phase used for the "+" sign contacts. It should be
appreciated that the APSM technique is utilized to ensure that
adjacent contacts are separated from each other.
[0099] As feature sizes decrease, semiconductor dies are capable of
including more gates. As more gates are included, however, the
density of the interconnect layers begins to dictate the die size.
This increasing demand on the interconnect layers drives higher
levels of interconnect layers. However, the stacking of
interconnect layers is limited in part by the topology of the
underlying layers. For example, as interconnect layers are built
up, islands, ridges, and troughs can occur. These islands, ridges,
and troughs can cause breaks in the interconnect lines that cross
them.
[0100] To mitigate these islands and troughs, the semiconductor
manufacturing process utilizes a chemical mechanical polishing
(CMP) procedure to mechanically and chemically polish the surface
of the semiconductor wafer such that each subsequent interconnect
layer is deposited on a substantially flat surface. Like the
photolithography process the quality of the CMP process is layout
pattern dependent. Specifically, an uneven distribution of a layout
features across a die or a wafer can cause too much material to be
removed in some places and not enough material to be removed in
other places, thus causing variations in the interconnect thickness
and unacceptable variations in the capacitance and resistance of
the interconnect layer. The capacitance and resistance variation
within the interconnect layer may alter the timing of a critical
net causing design failure.
[0101] The CMP process requires that dummy fill be added in the
areas without interconnect shapes so that a substantially uniform
wafer topology is provided to avoid dishing and improve
center-to-edge uniformity. Traditionally, dummy fill is placed
post-design. Thus, in the traditional approach the designer is not
aware of the dummy fill characteristics. Consequently, the dummy
fill placed post-design may adversely influence the design
performance in a manner that has not been evaluated by the
designer. Also, because the conventional topology prior to the
dummy fill is unconstrained, i.e., non-uniform, the post-design
dummy fill will not be uniform and predictable. Therefore, in the
conventional process, the capacitive coupling between the dummy
fill regions and the neighboring active nets cannot be predicted by
the designer.
[0102] As previously discussed, the dynamic array disclosed herein
provides optimal regularity by maximally filling all interconnect
tracks from gate electrode layer upward. If multiple nets are
required in a single interconnect track, the interconnect track is
split with a minimally spaced gap. For example, track 809
representing the metal 1 conduction line in FIG. 8A represents
three separate nets in the same track, where each net corresponds
to a particular track segment. More specifically, there are two
poly contact nets and a floating net to fill the track with minimal
spacing between the track segments. The substantially complete
filling of tracks maintains the regular pattern that creates
resonant images across the dynamic array. Also, the regular
architecture of the dynamic array with maximally filled
interconnect tracks ensures that the dummy fill is placed in a
uniform manner across the die. Therefore, the regular architecture
of the dynamic array assists the CMP process to produce
substantially uniform results across the die/wafer. Also, the
regular gate pattern of the dynamic array assists with gate etching
uniformity (microloading). Additionally, the regular architecture
of the dynamic array combined with the maximally filled
interconnect tracks allows the designer to analyze the capacitive
coupling effects associated with the maximally filled tracks during
the design phase and prior to fabrication.
[0103] Because the dynamic array sets the size and spacing of the
linearly shaped features, i.e., tracks and contacts, in each mask
layer, the design of the dynamic array can be optimized for the
maximum capability of the manufacturing equipment and processes.
That is to say, because the dynamic array is restricted to the
regular architecture for each layer above diffusion, the
manufacturer is capable of optimizing the manufacturing process for
the specific characteristics of the regular architecture. It should
be appreciated that with the dynamic array, the manufacturer does
not have to be concerned with accommodating the manufacture of a
widely varying set of arbitrarily-shaped layout features as is
present in conventional unconstrained layouts.
[0104] An example of how the capability of manufacturing equipment
can be optimized is provided as follows. Consider that a 90 nm
process has a metal 2 pitch of 280 nm. This metal 2 pitch of 280 nm
is not set by the maximum capability of equipment. Rather, this
metal 2 pitch of 280 nm is set by the lithography of the vias. With
the via lithography issues removed, the maximum capability of the
equipment allows for a metal 2 pitch of about 220 nm. Thus, the
design rules for metal 2 pitch include about 25% margin to account
for the light interaction unpredictability in the via
lithography.
[0105] The regular architecture implemented within the dynamic
array allows the light interaction unpredictability in the via
lithography to be removed, thus allowing for a reduction in the
metal 2 pitch margin. Such a reduction in the metal 2 pitch margin
allows for a more dense design, i.e., allows for optimization of
chip area utilization. Additionally, with the restricted, i.e.,
regular, topology afforded by the dynamic array, the margin in the
design rules can be reduced. Moreover, not only can the excess
margin beyond the capability of the process be reduced, the
restricted topology afforded by the dynamic array also allows the
number of required design rules to be substantially reduced. For
example, a typical design rule set for an unconstrained topology
could have more than 600 design rules. A design rule set for use
with the dynamic array may have about 45 design rules. Therefore,
the effort required to analyze and verify the design against the
design rules is decreased by more than a factor of ten with the
restricted topology of the dynamic array.
[0106] When dealing with line end-to-line end gaps (i.e., track
segment-to-track segment gaps) in a given track of a mask layer in
the dynamic array, a limited number of light interactions exist.
This limited number of light interactions can be identified,
predicted, and accurately compensated for ahead of time,
dramatically reducing or completely eliminating the requirement for
OPC/RET. The compensation for light interactions at line
end-to-line end gaps represents a lithographic modification of the
as-drawn feature, as opposed to a correction based on modeling of
interactions, e.g., OPC/RET, associated with the as-drawn
feature.
[0107] Also, with the dynamic array, changes to the as-drawn layout
are only made where needed. In contrast, OPC is performed over an
entire layout in a conventional design flow. In one embodiment, a
correction model can be implemented as part of the layout
generation for the dynamic array. For example, due to the limited
number of possible line end gap interactions, a router can be
programmed to insert a line break having characteristics defined as
a function of its surroundings, i.e., as a function of its
particular line end gap light interactions. It should be further
appreciated that the regular architecture of the dynamic array
allows the line ends to be adjusted by changing vertices rather
than by adding vertices. Thus, in contrast with unconstrained
topologies that rely on the OPC process, the dynamic array
significantly reduces the cost and risk of mask production. Also,
because the line end gap interactions in the dynamic array can be
accurately predicted in the design phase, compensation for the
predicted line end gap interactions during the design phase does
not increase risk of design failure.
[0108] In conventional unconstrained topologies, designers are
required to have knowledge of the physics associated with the
manufacturing process due to the presence of design dependent
failures. With the grid-based system of the dynamic array as
disclosed herein, the logical design can be separated from the
physical design. More specifically, with the regular architecture
of the dynamic array, the limited number of light interactions to
be evaluated within the dynamic array, and the design independent
nature of the dynamic array, designs can be represented using a
grid point based netlist, as opposed to a physical netlist.
[0109] With the dynamic array, the design is not required to be
represented in terms of physical information. Rather, the design
can be represented as a symbolic layout. Thus, the designer can
represent the design from a pure logic perspective without having
to represent physical characteristics, e.g., sizes, of the design.
It should be understood that the grid-based netlist, when
translated to physical, matches the optimum design rules exactly
for the dynamic array platform. When the grid-based dynamic array
moves to a new technology, e.g., smaller technology, a grid-based
netlist can be moved directly to the new technology because there
is no physical data in the design representation. In one
embodiment, the grid-based dynamic array system includes a rules
database, a grid-based (symbolic) netlist, and the dynamic array
architecture.
[0110] It should be appreciated that the grid-based dynamic array
eliminates topology related failures associated with conventional
unconstrained architectures. Also, because the manufacturability of
the grid-based dynamic array is design independent, the yield of
the design implemented on the dynamic array is independent of the
design. Therefore, because the validity and yield of the dynamic
array is preverified, the grid-based netlist can be implemented on
the dynamic array with preverified yield performance.
[0111] FIG. 14 is an illustration showing a semiconductor chip
structure 1400, in accordance with one embodiment of the present
invention. The semiconductor chip structure 1400 represents an
exemplary portion of a semiconductor chip, including a diffusion
region 1401 having a number of conductive lines 1403A-1403G defined
thereover. The diffusion region 1401 is defined in a substrate
1405, to define an active region for at least one transistor
device. The diffusion region 1401 can be defined to cover an area
of arbitrary shape relative to the substrate 1405 surface.
[0112] The conductive lines 1403A-1403G are arranged to extend over
the substrate 1405 in a common direction 1407. It should also be
appreciated that each of the number of conductive lines 1403A-1403G
are restricted to extending over the diffusion region 1401 in the
common direction 1407. In one embodiment, the conductive lines
1403A-1403G defined immediately over the substrate 1405 are
polysilicon lines. In one embodiment, each of the conductive lines
1403A-1403G is defined to have essentially the same width 1409 in a
direction perpendicular to the common direction 1407 of extension.
In another embodiment, some of the conductive lines 1403A-1403G are
defined to have different widths relative to the other conductive
lines. However, regardless of the width of the conductive lines
1403A-1403G, each of the conductive lines 1403A-1403G is spaced
apart from adjacent conductive lines according to essentially the
same center-to-center pitch 1411.
[0113] As shown in FIG. 14, some of the conductive lines
(1403B-1403E) extend over the diffusion region 1401, and other
conductive lines (1403A, 1403F, 1403G) extend over non-diffusion
portions the substrate 1405. It should be appreciated that the
conductive lines 1403A-1403G maintain their width 1409 and pitch
1411 regardless of whether they are defined over diffusion region
1401 or not. Also, it should be appreciated that the conductive
lines 1403A-1403G maintain essentially the same length 1413
regardless of whether they are defined over diffusion region 1401
or not, thereby maximizing lithographic reinforcement between the
conductive lines 1403A-1403G across the substrate. In this manner,
some of the conductive lines, e.g., 1403D, defined over the
diffusion region 1401 include a necessary active portion 1415, and
one or more uniformity extending portions 1417.
[0114] It should be appreciated that the semiconductor chip
structure 1400 represents a portion of the dynamic array described
above with respect to FIGS. 2-13D. Therefore, it should be
understood that the uniformity extending portions 1417 of the
conductive lines (1403B-1403E) are present to provide lithographic
reinforcement of neighboring conductive lines 1403A-1403G. Also,
although they may not be required for circuit operation, each of
conductive lines 1403A, 1403F, and 1403G are present to provide
lithographic reinforcement of neighboring conductive lines
1403A-1403G.
[0115] The concept of the necessary active portion 1415 and the
uniformity extending portions 1417 also applies to higher level
interconnect layers. As previously described with regard to the
dynamic array architecture, adjacent interconnect layers traverse
over the substrate in transverse directions, e.g., perpendicular or
diagonal directions, to enable routing/connectivity required by the
logic device implemented within the dynamic array. As with the
conductive lines 1403A-1403G, each of the conductive lines within
an interconnect layer may include a required portion (necessary
active portion) to enable required routing/connectivity, and a
non-required portion (uniformity extending portion) to provide
lithographic reinforcement to neighboring conductive lines. Also,
as with the conductive lines 1403A-1403G, the conductive lines
within an interconnect layer extend in a common direction over the
substrate, have essentially the same width, and are spaced apart
from each other according to an essentially constant pitch.
[0116] In one embodiment, conductive lines within an interconnect
layer follow essentially the same ratio between line width and line
spacing. For example, at 90 nm the metal 4 pitch is 280 nm with a
line width and line spacing equal to 140 nm. Larger conductive
lines can be printed on a larger line pitch if the line width is
equal to the line spacing.
[0117] FIG. 15 shows an example layout architecture defined in
accordance with one embodiment of the present invention. The layout
architecture follows a grid pattern and is based upon a horizontal
grid and a vertical grid. The horizontal grid is set by the poly
gate pitch. The vertical pitch is set by the metal 1/metal 3 pitch.
All of the rectangular shapes should be centered on a grid point.
The layout architecture minimizes the use of bends to eliminate
unpredictable lithographic interactions. Bends are allowed on the
diffusion layer to control transistor device sizes. Other layers
should be rectangular in shape and fixed in one dimension.
[0118] The invention described herein can be embodied as computer
readable code on a computer readable medium. The computer readable
medium is any data storage device that can store data which can be
thereafter be read by a computer system. Examples of the computer
readable medium include hard drives, network attached storage
(NAS), read-only memory, random-access memory, CD-ROMs, CD-Rs,
CD-RWs, magnetic tapes, and other optical and non-optical data
storage devices. The computer readable medium can also be
distributed over a network coupled computer systems so that the
computer readable code is stored and executed in a distributed
fashion. Additionally, a graphical user interface (GUI) implemented
as computer readable code on a computer readable medium can be
developed to provide a user interface for performing any embodiment
of the present invention.
[0119] While this invention has been described in terms of several
embodiments, it will be appreciated that those skilled in the art
upon reading the preceding specifications and studying the drawings
will realize various alterations, additions, permutations and
equivalents thereof. Therefore, it is intended that the present
invention includes all such alterations, additions, permutations,
and equivalents as fall within the true spirit and scope of the
invention.
* * * * *