Method of determining FET source/drain wire, contact, and diffusion

Method of determining FET source/drain wire, contact, and diffusion
US008479131B2
(12) United States Patent
(10) Patent N0.:
(45) Date of Patent:
Dewey, III et al.
(54)
METHOD OF DETERMINING FET
SOURCE/DRAIN WIRE, CONTACT, AND
DIFFUSION RESISTANCES IN THE
PRESENCE OF MULTIPLE CONTACTS
(75) Inventors: Lewis W. Dewey, III, Wappingers Falls,
NY (U S); Ning Lu, Essex Junction, VT
(US); Judith H. McCullen, Essex
Junction, VT (US); Cole E. Zemke,
Essex Junction, VT (US)
(73) Assignee: International Business Machines
Corporation, Armonk, NY (US)
(*)
Notice:
Subject to any disclaimer, the term of this
patent is extended or adjusted under 35
U.S.C. 154(b) by 155 days.
Jul. 2, 2013
FOREIGN PATENT DOCUMENTS
JP
JP
2003 -223478
2006-260200
8/2003
9/2006
OTHER PUBLICATIONS
Lu, Ning; Dewey, Bill; “Characterization, Simulation, and Modeling
of PET Source/Drain Diffusion Resistance,” 2008, IEEE.*
Wong, Waisum; Shao, Fang; Huang, Andy; Ko, Tienchi; Lee, Scott;
Qian, Weihong; Liao, Chinchang; Gao, Xiaofang; TaZlauana, Mihai;
Liu, Weidong; “Scalable Modeling of MOSFET Source and Drain
Resistances for MS/RF Circuit Simulation,” 2006, IEEE.*
BSIM4.5 MOSFET Model, User’s Manual, UC Berkeley, Chapter
11, “Layout-Dependent Parasitics Model,” 2003, 9 pages.
BSIM4.5 MOSFET Model, User’s Manual, UC Berkeley, Appendix
A.11, “Layout-Dependent Parasitics Model,” 2003, 42 pages.
Lu, et al., “Characterization, Simulation, and Modeling of PET
Source/ Drain Diffusion Resistance,” IEEE 2008 Custom Integrated
Circuits Conference, 2008, pp. 281-284.
* cited by examiner
(21) App1.No.: 13/038,468
(22) Filed:
US 8,479,131 B2
Primary Examiner * Vuthe Siek
Assistant Examiner * Eric Lee
Mar. 2, 2011
(74) Attorney, Agent, or Firm * Gibb & Riley, LLC;
(65)
US 2012/0227020 A1
(51)
(52)
Int. Cl.
G06F 17/50
US. Cl.
USPC
(58)
Richard M. Kotulak, Esq.
Prior Publication Data
Sep. 6, 2012
(57)
effect transistor (FET) device. The method counts the number
(2006.01)
(N) of contacts in each source/drain region of the FET device,
partitions each source/ drain region into N contact regions and
......................................... .. 716/110;716/115
Field of Classi?cation Search
USPC
........................................................ .. 716/110
See application ?le for complete search history.
(56)
ABSTRACT
A method calculates a total source/drain resistance for a ?eld
References Cited
calculates a set of resistances of elements and connections to
the FET device. The measured dimensions of Widths, lengths,
and distances of layout shapes forming the PET and the
connections to the FET are determined and a set of Weights
based on relative Widths of the contact regions are computed.
The total source/drain resistance of the FET device is deter
mined by summing products of the set of resistances and the
Us‘ PATENT DOCUMENTS
5,461,579 A
10/ 1995 Misheloff et 31
set of Weights for each of a plurality of contacts in series, the
summing being performed for all of the plurality of contacts
5,896,300 A
6,438,729 B1
in one of a source region and a drain region of the FET. A
t1. t. f
db
d
th t t 1
. t
dt t 1
6,665,845 B1
4/1999 Raghavan et a1‘
8/2002 Ho
12/2003 Aingamn et a1‘
6,854,103 B2
7,114,137 B2
2/2005 Teene
9/2006 Hayashi
7,320,116 B2
l/2008 Mukaihira
ne ‘1s 1s .orme
ase on
e o'a source res1s ance an
dram res1stance of the FET device.
19 Claims, 12 Drawing Sheets
DETERMINING, BYA COMPUTING DEVICE, PHYSICAL RESISTANCES OFA WIRE ’\ 500
RESISTANCE (!),ACONTACT RESISTANCE (Ru), ANDADIFFLISION
RESISTANCE
I
I
FOR EACH OF THE PLURALITV OF CONTACTS
I
I
DETERMININGACONTACTIDIFFLISION RESISTANCE WEIGHT
I
DETERMININGAWIRE RESISTANCE WEIGHT
IASOZ
p504
DETERMINING AN EFFECTIVE RESISTANCE IRE’) FOR EACH OF THE FLURALITY “505
OF CONTACTS BY SUMMING IN SERIES FOR EACH PARTICULAR CONTACT THE
PRODUCTS OF:
1)THE WIRE RESISTANCE WEIGHTAND THE WIRE RESISTANCE In,
2) THE CONTACT/DIFFUSION RESISTANCE WEIGHTAND THE CONTACT
RESISTANCE (Ru), AND
3) THE CONTACT/DIFFUSION RESISTANCE WEIGHTAND THE DIFFUSION
RESISTANCE (R).
DETERMINING, BY THE COMPUTING DEVICE, ATOTAI. SOURCE/DRAIN
RESISTANCE (Rm) FOR ONE OF A SOURCE REGION AND A DRAIN REGION BY
SUMMING IN SERIES EACH OF THE EFFECTIVE RESISTANCES (R5,) FOR
CONTACTS CONTAINED IN ONE OF THE SOURCE REGION AND THE DRAIN
REGION, RESPECTIVELY
608
OUTPUTTING ONE OF THE EFFECTIVE RESISTANCES (R5,) FOR EACH OF THE
PLURALITV OF CONTACTS AND THE TOTAL SOURCE/DRAIN RESISTANCE (RM)
FOR ONE OF THE SOURCE REGION AND THE DRAIN REGION
610
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US 8,479,131 B2
1
2
METHOD OF DETERMINING FET
mined by summing in series for each particular contact the
products of: the Wire resistance Weight and the Wire resistance
(r); the contact/diffusion resistance Weight and the contact
resistance (RCA), and the contact/diffusion resistance Weight
and the diffusion resistance (R). A total source/drain resis
SOURCE/DRAIN WIRE, CONTACT, AND
DIFFUSION RESISTANCES IN THE
PRESENCE OF MULTIPLE CONTACTS
BACKGROUND
tance (Rtot) for one of a source region and a drain region is
The present invention relates to a method of calculating the
total source/ drain resistance for a ?eld effect transistor (FET)
tances (REf) for contacts contained in one of the source region
determined by summing in series each of the effective resis
and the drain region, respectively. One of the effective resis
tances (REf) is output for each of the plurality of contacts and
device With multiple contacts in a single source/drain region,
and more speci?cally, it relates to a method of extracting and
the total source/drain resistance (Rtot) for one of the source
netlisting multiple diffusion resistance elements, multiple
region and the drain region.
contact resistance elements, and multiple segments of Wire
A further exemplary aspect of an embodiment herein
resistance elements for a FET device With multiple contacts in
includes a non-transitory computer storage medium storing
computer-readable instruction executable by a computer to
a single source/drain region.
When a source/ drain region of a FET device (or a bi-polar
device or a metal oxide semiconductor varactor) is contacted
by multiple contacts, there exists a need to calculate or extract
perform a method that determines a total source/drain resis
tance for a ?eld effect transistor (FET). The FET includes a
plurality of contacts on a Wire (M1) having an intersection
total source/ drain resistance of the FET device. In this patent,
When We say total source resistance, it includes diffusion
resistances, contact resistances, and Wire resistances at a
FET’s source side. Similarly, in this patent, When We say total
drain resistance, it includes diffusion resistance, contact
resistance, and Wire resistance at a FET’s drain side. Using
conventional calculation or extraction methods, hoWever, it is
dif?cult to correctly calculate or correctly extract and netlist
the total source/drain resistance coming from multiple diffu
sion resistance elements, multiple contact resistance ele
ments, and multiple segments of Wire resistance elements.
20
With a diffusion region (RX) at a ?rst edge of the diffusion
region. The diffusion region (RX) has a total diffusion region
Width (WRX) de?ned as a dimension betWeen the ?rst edge
25
and a second edge of the diffusion region opposite the inter
section at the diffusion region (RX) ?rst edge. The method
counts the number (N) of contacts in each source/ drain region
of the FET device, partitions each source/drain region into N
contact region and determining resistances of a Wire resis
tance (r), a contact resistance (RCA), and a diffusion resistance
30
SUMMARY
(R) for each of the plurality of contacts to the FET. A Wire
resistance Weight and a contact/diffusion resistance Weight
are determined. An effective resistance (REf) for each of the
plurality of contacts is determined by summing in series for
An exemplary aspect of an embodiment herein includes a
computer-implemented method that calculates a total source/
drain resistance of a ?eld effect transistor (FET) device. The
method counts the number (N) of contacts in each source/
each particular contact the products of: the Wire resistance
Weight and the Wire resistance (r); the contact/diffusion resis
35
tance Weight and the contact resistance (RCA), and the con
tact/diffusion resistance Weight and the diffusion resistance
drain region of the FET device, partitions each source/drain
(R). A total source/drain resistance (Rtot) for one of a source
region into N contact regions and calculates a set of resis
tances of elements and connections to the FET device. The
region and a drain region is determined by summing in series
each of the effective resistances (REf) for contacts contained
measured dimensions of Widths, lengths, and distances of
layout shapes forming the FET and the connections to the
40
in one of the source region and the drain region, respectively.
One of the effective resistances (RE?) is output for each of the
plurality of contacts and the total source/ drain resistance
(Rtot) for one of the source region and the drain region.
45
BRIEF DESCRIPTION OF THE SEVERAL
VIEWS OF THE DRAWINGS
FET are determined and a set of Weights based on relative
Widths of the contact regions are computed. The total source/
drain resistance of the FET device is determined by summing
products of the set of resistances and the set of Weights for
each of a plurality of contacts in series, the summing being
performed for all of the plurality of contacts in one of a source
FIG. 1 is a typical FET layout With multiple contacts in its
source region and multiple contacts in its drain region;
region and a drain region of the FET. A netlist is formed based
on the total source resistance and total drain resistance of the
FET device.
50
Another exemplary aspect of an embodiment herein
FIG. 2 schematically shoWs physical Wire, contact, and
diffusion resistive elements in source and drain regions for the
includes a computer-implemented method that determines a
FET layout in FIG. 1;
total source/ drain resistance for a ?eld effect transistor (FET).
FIG. 3 is a conventional netlist on Wire, contact, and diffu
sion resistive elements in source and drain regions for the FET
The FET includes a plurality of contacts on a Wire (M1)
having an intersection With a diffusion region (RX) at a ?rst
55
edge of the diffusion region. The diffusion region (RX) has a
FIG. 4 is a schematic diagram of an embodiment herein;
FIG. 5 is a netlist diagram of an embodiment herein;
FIG. 6 is an alternative netlist diagram of an embodiment
total diffusion region Width (WRX) being de?ned as a dimen
sion betWeen the ?rst edge and a second edge of the diffusion
region opposite the intersection at the diffusion region (RX)
?rst edge. The method counts the number (N) of contacts in
layout in FIG. 1;
herein;
60
FIG. 7 is a logic ?owchart diagram of a method of an
each source/drain region of the FET device, partitions each
source/drain region into N contact regions and determines
embodiment herein;
resistances of a Wire resistance (r), a contact resistance (RCA),
and a diffusion resistance (R) for each of the plurality of
contacts to the FET. A Wire resistance Weight and a contact/
diffusion resistance Weight are determined. An effective
execution of a transitory computer program thereupon;
resistance (REf) for each of the plurality of contacts is deter
FIG. 8 is a schematic diagram of a computer system for
FIG. 9 is a schematic diagram of a deployment system
65
according to embodiments herein;
FIG. 10 is a schematic diagram of an integration system
according to embodiments herein;
US 8,479,131 B2
4
3
?rst diffusion edge. The method further includes determining
FIG. 11 is a schematic diagram of an on demand system
according to embodiments herein; and
resistances of a Wire resistance (loWer case r), a contact resis
FIG. 12 is a schematic diagram of a virtual private network
tance (RCA), and a diffusion resistance (upper case R) for each
system according to embodiments herein.
of the plurality of contacts. The computer program product
includes a non-transitory computer readable storage medium
having computer readable program code embodied thereWith,
DETAILED DESCRIPTION
the computer readable program code causes a computer to
determine resistances of a Wire resistance (r), a contact resis
One embodiment includes a PET With multiple contacts in
a source/drain region. This portion of the disclosure (i) pre
tance (RCA), and a diffusion resistance (R) for each of the
plurality of contacts, and to determine a Wire resistance
Weight and a contact/diffusion resistance Weight. The pro
gram code is further con?gured to determine an effective
sents a method to extract and netlist multiple diffusion resis
tance elements, multiple contact resistance elements, and
multiple segments of Wire resistance elements using a para
sitic extraction tool, (ii) a method of extracting and calculat
ing total FET source/drain resistance, and (iii) a method of
generating a much simpli?ed netlist. These methods also
resistance (RE?) for each of the plurality of contacts by sum
ming in series for each particular contact the products of: l)
the Wire resistance Weight and the Wire resistance (r); 2) the
contact/diffusion resistance Weight and the contact resistance
(RCA); and 3) the contact/ diffusion resistance Weight and the
diffusion resistance (R). The program code is further con?g
apply to a diffusion region of a MOS varactor.
Another embodiment of the present invention calculates a
total source/drain resistance of a PET device. This embodi
ment calculates a set of physical resistances of the PET, and
determines measured dimensions of Widths, lengths, and dis
tances of layout shapes forming the PET and connections to
ured to determine a total source/ drain resistance (Rtot) for the
20
source region or the drain region by summing in series each of
the effective resistances (REf) for contacts contained in the
source region or the drain region, respectively, and ?nally
output to the effective resistances (REf) for each of the con
25
region or the drain region.
A ?rst embodiment comprises a method of calculating the
total resistance of PET parasitic elements (such as source/
drain regions and associated contacts), taking into account
the FET. This embodiment computes a set of Weights based
on the relative siZes of the measured dimensions, and deter
mines the total source/ drain resistance of the FET device by
summing the products of the set of physical resistances and
the set of Weights for each of the contacts (in series), and does
tacts and the total source/drain resistance (Rm) for the source
so for all of the plurality of contacts in the source region or the
drain region. From this, the embodiment forms a netlist based
on the determined total source/drain resistance of the FET
device. Another embodiment of the present invention deter
30
mines a PET source/drain resistance for a PET that has a
plurality of contacts on a Wire (M1) having an intersection
With a diffusion region (RX) at a ?rst edge of the diffusion
region. The FET has a Width (W) de?ned as a dimension
betWeen a ?rst edge of the diffusion region and a second edge
35
of the diffusion region. The ?rst edge of the diffusion region
is de?ned as a diffusion edge for electric current ?oW over it
in an M1 Wire. In FET layout, the ?rst edge of the diffusion
region typically is that diffusion edge Which intersects the
Wire (M1). The second edge of the diffusion region is the
other edge, Which is opposite the ?rst diffusion edge. The
40
multiple diffusion resistance elements (R), multiple contact
resistance elements (RCA), and multiple segments of Wire
(M1) resistance elements (r). An additional embodiment
includes a method of extracting and netlisting multiple dif?l
sion resistance elements, multiple contact resistance ele
ments, and multiple segments of Wire resistance elements in
the output of a parasitic resistance extraction tool.
In the ?rst embodiment, multiple diffusion resistance ele
ments, multiple contact resistance elements, and the resis
tance elements of multiple Wire segments are included. Here,
a PET total source/drain resistance (Rtot) is determined for the
source region or the drain region by summing (in series) each
of the effective resistances (REf) for contacts contained in the
source region or the drain region, respectively. Let the contact
number for a source/drain region be N, let j” be the electric
method further includes determining resistances of a Wire
resistance (loWer case r), a contact resistance (RCA), and a
diffusion resistance (upper case R) for each of the plurality of
current going into (or coming out of) the nth contact (n:l,
contacts. For each contact resistance and associated diffusion
resistance, a Weight for its contribution to a total resistance is
determined. For the resistance of each Wire segment connect
ing tWo contacts, a Weight for its contribution to the total
resistance is also determined. Wcightcd rcsistanccs are
45 2, . . . , N). The total electric current passing through that
assigned to each diffusion resistance element, each contact
resistance element, and each Wire segment resistance ele
ment. A total source/drain resistance (Rtot) is determined by
50
segment of M1 Wire Which connects the nth and (n+l)th con
tacts is de?ned as:
(1)
:
»
H
summing (namely, resistive elements being connected in
series in a netlist) the products of: l) the Wire resistance
Weight and the Wire resistance (r); 2) the contact/diffusion
resistance Weight and the contact resistance (RCA); and 3) the
55
tive resistance to the end of the (n+l)th Wire segment, RE?H 1,
contact/diffusion resistance Weight and the diffusion resis
tance (R).
Another embodiment of the present invention includes a
computer program product for determining a PET source/
An iteration relationship exists betWeen the effective resis
tance to the end of the nth Wire segment, RE173”, and the effec
2
-2
60
drain resistance for a PET that has a plurality of contacts
betWeen a diffusion region (RX) and a Wire (M1). The FET
has a Width (WRX) de?ned as a dimension betWeen a ?rst edge
of the diffusion region and a second edge of the diffusion
region. The ?rst edge of the diffusion region is de?ned as a
diffusion edge Which intersects the Wire. The second edge of
the diffusion region is the other edge Which is opposite the
Where r” is the Wire resistance of the nth partition region of a
diffusion region, and R” is the sum of diffusion and contact
65
(CA) resistance in the nth partition of the diffusion region,
,N
US 8,479,131 B2
6
5
Using the iteration relation (2), the effective resistance is
obtained up to the end of the nth Wire segment,
The embodiments herein extract and pass more geometric
parameters to parasitic resistance models (or to other func
tions inside an extraction tool) With respect to:
a. a contact resistance, that passes either a ratio (Wn/WRX)2
l
N
2
2
(4)
5
REff = T E (1111?” +41%)
N ":1
to a contact resistance model, or change the via number
(connected in parallel) from a true value of 1 to an
equivalent value of (WRX/Wn)2 (a real value in general);
b. a diffusion resistance, that passes either a multiplier
(Wn/WRX)2 or the FET total Width parameter WRX to a
If the metal Wire resistance is ignored, then the sum of the
diffusion and contact resistances, R”, is connected in parallel
10
center of the (n+1)th contact], a modi?ed length Ln(vvn/
nected in series in the layout. When all three types of resis
tance (diffusion, contact, and M1 Wire resistances) are
included, then their connection is a combination of having
both parallel connection and serial connection. Nevertheless,
WRX)2 may be passed to a Wire resistance model.
Optionally, a post-processor can combine 3N resistance
elements (N diffusion Resistance elements, N contact resis
tance elements, and N metal Wire resistance elements) into a
Single total resistance element for each of the source and
in a netlist or in an extraction deck, they may be connected in
series and are also associated With Weights. The nth Weight for
diffusion and contact resistance is (jn/It0t)2, but the nth Weight
for the metal (say, Ml) Wire resistance is(In /It0t)2. For the
metal Wire resistance, the numbering of 1“ vs. 2”dvs. 3’dis not
drain regions.
20
Another application of the method in this disclosure is in
schematic FET models Where all diffusion resistance, contact
resistance, and M1 Wire resistance in the FET’s source end
can be combined into a single source-side resistor element,
and all diffusion resistance, contact resistance, and M1 Wire
25
resistance in the FET’s drain end can be combined into a
arbitrary. The 1 S’ segment of Wire carries the smallest current,
and the last segment carries all current passing through the
FET.
When all partition Widths W” are much smaller than a
diffusion resistance model; and
c. a Wire resistance model, instead of passing its true length
L” [the distance from the center of the nth contact to the
in the layout. If both diffusion and contact resistances are
ignored, then the metal Wire resistance elements r” are con
characteristic Width value WO (Which depends on FET maxi
mum effective current and Vdd, etc.), the current j” is propor
tional to the Width W” of the nth partition region,
single drain-side resistor element.
FIG. 1 shoWs a typical FET layout With multiple contacts in
its source region and multiple contacts in its drain region. In
FIG. 1, a polysilicon (PC) gate 102 intersecting diffusion
(5)
30 region (RX) 106 de?nes a PET. One side of diffusion region
RX 106, outside PC gate 102, de?nes a source region, and the
MW", W.<<WO, 11:1, 2, - - - ,N
other side of diffusion region RX 106, outside PC gate 102,
Total resistance (4) simpli?es to
de?nes a drain region. A Wire M1 100 connects multiple
contacts (CA) CAl 108, CA2 110, CA3 112 located in the
source region. A second Wire M1‘ 104 connects multiple
contacts CA1‘ 114, CA2‘ 116 and CA3‘ 118 in the drain region.
FIG. 2 schematically shoW physical Wire, contact, and
40
diffusion resistive elements in source and drain regions for the
FET layout in FIG. 1.
In the source region, there are a physical Wire resistance r51,
a physical diffusion resistance RS1, and a physical contact
(CA) resistance RSCAl (in the proximity of the contact CAl
is the total Width from the beginning of the 1S’ partition region
to the end of the nth partition region, and
WRKWN
(8)
is the FET Width.
One embodiment presented herein includes a model/mod
ule/function to calculate/ estimate the diffusion resistance in a
108). Their contribution to total source resistances may be
modeled as an effective resistance RSE17; 1.
45
contact (CA) resistance RSCA2 (in the proximity of the contact
50
single diffusion region’ s partition, With the capability to mul
tiply the resistance by another real value (i.e., an instance
parameter). A model/module/function returns contact resis
tance, With an instance parameter to indicate the number of
contacts connected in parallel, and a model/module/ function
to calculate Wire resistance, With one of the instance param
55
114). Their contribution to total drain may be modeled as an
drain region, the corresponding netlist includes 1 Wire resis
bined (diffusion +contact) resistance element.
Instead of a parallel connection, or a more complex con
nection When M1 Wire resistance is included, one embodi
ment connects the resistance elements for all Wire segments,
CA3 112). Their contribution to total source resistances may
be modeled as an effective resistance RSEjB.
In the drain region, there are a physical Wire resistance rdl ,
a physical diffusion resistance Rdp, and a physical contact
(CA) resistance RdCAl, (in the proximity of the contact CA1,
For each contact of multiple contacts in a single source/
resistance element, or 1 Wire resistance element and 1 com
CA2 110). Their contribution to total source resistances may
be modeled as an effective resistance RSE?Z.
Still in the source region, there are a physical Wire resis
tance r53, a physical diffusion resistance RS3, and a physical
contact (CA) resistance RSCA3 (in the proximity of the contact
eters being the Wire length.
tance element, 1 diffusion resistance element, and 1 contact
Also in the source region, there are a physical Wire resis
tance r52, a physical diffusion resistance RS2, and a physical
60
effective resistance RdE?l, for the contact CA1, 114.
In the proximity of the contact CA2, 1 1 6 located in the drain
region, there are a physical Wire resistance rd2,, a physical
diffusion resistance Rdzv, and a physical contact (CA) resis
tance Rd012,. Their contribution to total drain resistances may
be modeled as an effective resistance RdEfJ.
all contacts, and all source/drain partitions in series (and uses
In the proximity of the contact CA3, 1 18 located in the drain
region, there are a physical Wire resistance rd3v, a physical
Weights for those component elements).
diffusion resistance Rd3v, and a physical contact (CA) resis
US 8,479,131 B2
7
8
tance RdC/13 .. Their contribution to total drain resistances may
be modeled as an effective resistance R dE?y.
is merely being characterized by the edge Where the Wire M1
100 intersects the diffusion region RX 106. Note also that
cumulative Width V1153 is equal to the total Width of the diffu
FIG. 3 is a prior-art netlist on Wire, contact, and diffusion
resistive elements in source and drain regions for the FET
sion region WRX.
layout in FIG. 1.
For the drain region, the cumulative Width vii d1, for the
FIG. 4 is a schematic diagram that measures dimension
contact CA1, 114 closest to the opposite edge 300 (as de?ned
by the intersection of Wire M1‘ 104 intersection diffusion
parameters of the diffusion region RX 106, the dimension
parameters of the Wires M1 100 and M1‘ 104, and position
parameters of each of the contacts CA (108-118) in each
region RX 106) of the diffusion region is de?ned as a distance
from the opposite edge 300 of the diffusion region RX 106 to
a midpoint 308 of an adjacent contact CA2, 116. The cumu
lative Width vAvdz for contact CA2, is de?ned as a distance from
the opposite edge 300 of the diffusion region RX 106 to a
midpoint 310 of a next adjacent contact CA3v 118. Finally, the
cumulative Width \9vd3, for contact CA3, is de?ned as a distance
from the opposite edge 300 of the diffusion region RX 106 to
the edge 302 of the diffusion region RX 106. Note also that
cumulative Width vAvd3, is equal to the total Width of the diffu
source or drain region.
A total overall Width WRX of the diffusion region RX 1 06 is
measured from a ?rst edge 300 Where a Wire, for example, M1
100, intersects the diffusion region RX 106 to a second edge
302 of the diffusion region RX 106 opposite the ?rst edge
300.
Each of the contacts CA de?nes a contact region having a
contact region Width “Wn”. For example, source contact CAl
108 includes a source contact Width Wsl being de?ned
20
betWeen the second edge 302 of the diffusion region RX 106
FIG. 5 illustrates a schematic circuit diagram used to deter
mine the effective resistance of the multiple contacts in each
of the source and drain regions corresponding to FIGS. 1, 2,
and a midpoint 304 betWeen an adjacent contact, i.e., source
contact CA2 110. Source contact CA2 110 includes a source
contact Width WS2 being de?ned betWeen the midpoint 304
betWeen a ?rst adjacent contact, i.e., source contact CAl 108
sion region WRX.
and the midpoint 306 betWeen a second adjacent contact, i.e.,
and 4. For example, on the source side region on the M1 Wire
100, contact CA3 112 has three components that are com
puted in series to determine the effective resistance of contact
source contact CA3 112. Source contact CA3 112 includes a
CA3: K512117233
source contact Width WS3 being de?ned betWeen the ?rst edge
300 of the diffusion region RX 106 and the midpoint 306
betWeen an adjacent contact, i.e., source contact CA2 110.
Similarly, for the illustrated drain contacts (114-118), drain
contact CA1, 114 includes a drain contact Width Wdl, being
de?ned betWeen the ?rst edge 300 of the diffusion region RX
106 and a midpoint 308 betWeen an adjacent contact, i.e.,
drain contact CA2v 116. Drain contact CA2v 116 includes a
drain contact Width W being de?ned betWeen the midpoint
308 betWeen a ?rst adjacent contact, i.e., drain contact CA1,
114 and the midpoint 310 betWeen a second adjacent contact,
i.e., drain contact CA3v 118. Drain contact CA3v 118 includes
a drain contact Width W113v being de?ned betWeen the second
edge 302 of the diffusion region RX 106 and the midpoint 310
betWeen an adjacent contact, i.e., drain contact CA2, 116.
A cumulative Width dimension vii” used for modeling an
effective Wire resistance parameter is determined by a dimen
sion measured from an opposite edge of the diffusion region
25
1) a Wire resistance component equal to the product of the
resistance rs3 and the square of a ratio of the cumulative
30
Width measurement V2153 of contact CA3 to the overall
diffusion region Width WRX, i.e., rs3 (\9vS3/WRX)2;
2) a diffusion resistance component equal to the product of
the physical diffusion resistance RS3 and the square of a
ratio of the contact region Width WS3 of contact CA3 to
the overall diffusion region Width WRX, i.e., RS3(WS3/
WRX)2; and
40
3) a contact resistance component equal to the product of
the physical contact resistance RSCA3 and the square of
the ratio of the contact region Width WS3 of contact CA3
to the overall diffusion region Width WRX, i.e., RSCA3
(WS3/WRX)2'
45
To determine the effective resistance of contact CA2, RSE?
2, the folloWing three components are computed in series:
1) a Wire resistance component equal to the product of the
resistance rs2 and the square of a ratio of the cumulative
RX 106 With respect to an edge of the diffusion region RX 1 06
that is intersected by the Wire M1 or M1‘. For example, the
source region determines the cumulative Width vAvs from dif
Width measurement W52 of contact CA2 to the overall
Where Wire M1 100 intersects the diffusion region RX 106.
diffusion region Width WRX, i.e., rS2(\9vS2/WRX)2;
2) a diffusion resistance component equal to the product of
the physical diffusion resistance RS2 and the square of a
ratio of the contact region Width WS2 of contact CA2 to
Likewise, the drain region determines the cumulative Width
the overall diffusion region Width WRX, i.e., RS2(WS2/
fusion region edge 302 opposite the diffusion region edge 300
vAvd from diffusion region edge 300 opposite the diffusion
region edge 302 Where Wire M1‘ 104 intersects the diffusion
region RX 106.
For the source region, the cumulative Width \ilsl for the
contact CAl 108 closest to the opposite edge 302 of the
50
WRX)2; and
3) a contact resistance component equal to the product of
the physical contact resistance RSCA2 and the square of
the ratio of the contact region Width WS2 of contact CA2
to the overall diffusion region Width WRX, i.e., RSCA2
diffusion region is de?ned as a distance from the opposite
(WS2/WRX)2'
edge 302 of the diffusion region RX 106 to a midpoint 304 of 60
To determine the effective resistance of contact CA1, RSE?
1, the folloWing three components are computed in series:
an adjacent contact CA2 110. The cumulative Width V1152 for
1) a Wire resistance component equal to the product of the
contact CA2 is de?ned as a distance from the opposite edge
302 of the diffusion region RX 106 to a midpoint 306 of a next
resistance rsl and the square of a ratio of the cumulative
Width measurement \ilsl of contact CAl to the overall
adjacent contact CA3 112. Finally, the cumulative Width V1153
for contact CA3 is de?ned as a distance from the opposite
diffusion region Width WRX, i.e., rSl(\9vSl/WRX)2;
edge 302 of the diffusion region RX 106 to the “?rst” edge
300 of the diffusion region RX 106. Note that the “?rst” edge
2) a diffusion resistance component equal to the product of
the physical diffusion resistance RSl and the square of a
US 8,479,131 B2
10
FIG. 6 summarizes the schematic circuit diagram of FIG. 5
by simplifying each of the components of FIG. 5 for the
effective resistance of the source contacts, Rtot’soum and the
effective resistance of the drain contacts, R
being:
ratio of the contact region Width Wsl of contact CAl to
the overall diffusion region Width WRX, i.e., RS1(WSl/
WRX)2; and
3) a contact resistance component equal to the product of
the physical contact resistance RSCAl and the square of
the ratio of the contact region Width Wsl of contact CAl
5
to the overall diffusion region Width WRX, i.e., RSCAl
R 10!,source :
(Ws1/WRX)2'
Each of the source contact (108-112) effective resistances,
RSE?l, RSE1722, and RS E1733 are added in series to determine the
overall effective resistance of the multiple contacts in the
source region.
With respect to the drain contacts, (114-118), to determine
the effective resistance of contact CA1‘, RdE? 1,, the folloWing
three components are computed in series:
1) a Wire resistance component equal to the product of the
5
Where NS is the number of contacts in a source region, and Nd
is the number of contacts in a drain region.
FIG. 7 illustrates a logic ?owchart diagram of a method of
resistance rdlv and the square of a ratio of the cumulative
an embodiment that includes a computer-implemented
Width measurement vAvdl, of contact CA1, to the overall
20 method for determining a total source/drain resistance for a
diffusion region Width WRX, i.e., rdl,(\9vdl,/WRX)2;
PET. The FET has a plurality of contacts on a Wire (M1)
2) a diffusion resistance component equal to the product of
having
an intersection With a diffusion region (RX) at a ?rst
the physical diffusion resistance Rdl, and the square of a
edge of the diffusion region. The diffusion region (RX) has a
ratio of the contact region Width W d1, of contact CA1, to
total diffusion region Width (WRX) de?ned as a dimension
the overall diffusion region Width WRX, i.e., Rd1,(Wdl v/
WRX)2; and
3) a contact resistance component equal to the product of
the physical contact resistance RdcA1, and the square of
the ratio of the contact region Width W d1, of contact CA1,
to the overall diffusion region Width WRX, i.e., RdCAl,
(Wdl'/WRX)2'
To determine the effective resistance of contact CA2, RdE?
2', the folloWing three components are computed in series:
1) a Wire resistance component equal to the product of the
betWeen the ?rst edge and a second edge of the diffusion
region opposite the intersection at the diffusion region (RX)
?rst edge. The method determines 600 resistances of a Wire
resistance (r), a contact resistance (RCA), and a diffusion
0 resistance (R) for each of the plurality of contacts. A Wire
resistance Weight is determined 602, and a contact/diffusion
resistance Weight is determined 604.
Next, an effective resistance (RE?) is determined 606 for
each of the plurality of contacts by summing (in series) for
resistance rd2, and the square of a ratio of the cumulative 35 each particular contact the products of:
Width measurement vAvd2, of contact CA2, to the overall
diffusion region Width WRX, i.e., rd2,(vAvd2,/WRX)2;
the Wire resistance Weight and the Wire resistance (r),
the contact/diffusion resistance Weight and the contact
resistance (RCA), and
2) a diffusion resistance component equal to the product of
the contact/diffusion resistance Weight and the diffusion
the physical diffusion resistance Rdzv and the square of a
ratio of the contact region Width W112v of contact CA2, to 40 resistance (R).
A PET total source/drain resistance (Rtot) is determined
the overall diffusion region Width WRX, i.e., Rd2,(Wd2,/
608 for the source region or the drain region by summing in
WRX)2; and
series each of the effective resistances (REf) for contacts
3) a contact resistance component equal to the product of
contained in one of the source region and the drain region,
the physical contact resistance RdCAz and the square of
the ratio of the contact region Width W d2, of contact CA2, 45 respectively. Finally, the effective resistances (RE?) is output
610 for each of the plurality of contacts and the FET total
source/drain
resistance (Rtot) for the source region or the
(Wd2'/WRX)2'
to the overall diffusion region Width WRX, i.e., RdC/Q,
drain region.
To determine the effective resistance of contact CA3‘, RdE?
A set of the plurality of contacts may include source region
3', the folloWing three components are computed in series:
1) a Wire resistance component equal to the product of the 50 contacts or drain region contacts. The Wire resistance Weight
resistance rd3, and the square of a ratio of the cumulative
comprises a square of a ratio of a cumulative Width (vAvn) over
Width measurement vAvd3, of contact CA3, to the overall
the total diffusion region Width (WRX). The cumulative Width
(vvn) is de?ned for each contact of the plurality of contacts by
diffusion region Width WRX, i.e., rd3,(vAvd3,/WRX)2;
a dimension from the second edge of the diffusion region to a
2) a diffusion resistance component equal to the product of
the physical diffusion resistance Rae, and the square of a 55 distal edge of a contact region for a particular contact. The
distal edge of the contact region being de?ned by a midpoint
ratio of the contact region Width Wd3, of contact CA3v to
betWeen tWo adjacent contacts, or the ?rst edge of the diffu
the overall diffusion region Width WRX, i.e., Rd3,(Wd3,/
WRX)2; and
3) a contact resistance component equal to the product of
sion region.
The contact/ diffusion resistance Weight comprises a square
the physical contact resistance Rd013, and the square of 60 of a ratio of a contact region Width (Wn) over the total diffu
the ratio of the contact region Width W113v of contact CA3,
sion region Width (WRX). The contact region Width (Wn) is
to the overall diffusion region Width WRX, i.e., RdC/B,
de?ned for each contact of the plurality of contacts by a pair
of midpoints betWeen three adjacent contacts, a ?rst midpoint
betWeen tWo adjacent contacts and the ?rst edge of the diffu
(Wd3'/WRX)2'
Each of the drain contact (114-116) effective resistances,
RdE?l ., RdE?z and RdE?3v are added in series to determine the 65 sion region, or a second midpoint betWeen tWo adjacent con
tacts and the second edge of the diffusion region opposite the
overall effective resistance of the multiple contacts in the
drain region.
?rst edge.
US 8,479,131 B2
11
12
or computer program product. Accordingly, aspects of the
understood that each block of the ?owchart illustrations and/
or block diagrams, and combinations of blocks in the ?ow
chart illustrations and/ or block diagrams, can be imple
present invention may take the form of an entirely hardware
mented by computer program instructions. These computer
embodiment, an entirely software embodiment (including
?rmware, resident software, micro-code, etc.) or an embodi
ment combining software and hardware aspects that may all
program instructions may be provided to a processor of a
As will be appreciated by one skilled in the art, aspects of
the present invention may be embodied as a system, method
general purpose computer, special purpose computer, or other
programmable data processing apparatus to produce a
machine, such that the instructions, which execute via the
generally be referred to herein as a “circuit,” “module” or
“system.” Furthermore, aspects of the present invention may
processor of the computer or other programmable data pro
cessing apparatus, create means for implementing the func
tions/acts speci?ed in the ?owchart and/ or block diagram
take the form of a computer program product embodied in one
or more computer readable medium(s) having computer read
able program code embodied thereon.
block or blocks.
These computer program instructions may also be stored in
Any combination of one or more computer readable medi
um(s) may be utiliZed. The computer readable medium may
a computer readable medium that can direct a computer, other
be a computer readable signal medium or a computer read
programmable data processing apparatus, or other devices to
function in a particular manner, such that the instructions
stored in the computer readable medium produce an article of
able storage medium. A computer readable storage medium
may be, for example, but not limited to, an electronic, mag
manufacture including instructions which implement the
function/act speci?ed in the ?owchart and/or block diagram
netic, optical, electromagnetic, infrared, or semiconductor
system, apparatus, or device, or any suitable combination of
the foregoing. More speci?c examples (a non-exhaustive list)
20
of the computer readable storage medium would include the
block or blocks.
The computer program instructions may also be loaded
onto a computer, other programmable data processing appa
following: an electrical connection having one or more wires,
a portable computer diskette, a hard disk, a random access
ratus, or other devices to cause a series of operational steps to
memory (RAM), a read-only memory (ROM), an erasable
be performed on the computer, other programmable appara
programmable read-only memory (EPROM or Flash
memory), an optical ?ber, a portable compact disc read-only
memory (CD-ROM), an optical storage device, a magnetic
25
process such that the instructions which execute on the com
puter or other programmable apparatus provide processes for
implementing the functions/acts speci?ed in the ?owchart
storage device, or any suitable combination of the foregoing.
In the context of this document, a computer readable storage
medium may be any tangible medium that can contain, or
30
and/or block diagram block or blocks.
Referring now to FIG. 8, system 700 illustrates a typical
hardware con?guration which may be used for implementing
the inventive method for calculating a total source/drain resis
tance of the FET device. The con?guration has preferably at
least one processor or central processing unit (CPU) 710a,
store a program for use by or in connection with an instruction
execution system, apparatus, or device.
A computer readable signal medium may include a propa
gated data signal with computer readable program code
embodied therein, for example, in baseband or as part of a
carrier wave. Such a propagated signal may take any of a
tus or other devices to produce a computer implemented
35
7101). The CPUs 710a, 7101) are interconnected via a system
bus 712 to a random access memory (RAM) 714, read-only
variety of forms, including, but not limited to, electro-mag
memory (ROM) 716, input/output (I/O) adapter 718 (for con
netic, optical, or any suitable combination thereof. A com
necting peripheral devices such as disk units 721 and tape
drives 740 to the bus 712), user interface adapter 722 (for
connecting a keyboard 724, mouse 726, speaker 727, micro
phone 732, and/or other user interface device to the bus 712),
puter readable signal medium may be any computer readable
medium that is not a computer readable storage medium and
that can communicate, propagate, or transport a program for
use by or in connection with an instruction execution system,
apparatus, or device.
Program code embodied on a computer readable medium
40
may be transmitted using any appropriate medium, including
but not limited to wireless, wireline, optical ?ber cable, RF,
45
a communication adapter 734 for connecting an information
handling system to a data processing network, the Internet,
and Intranet, a personal area network (PAN), etc., and a dis
etc., or any suitable combination of the foregoing.
scanner 741 may be included. Such readers/ scanners are com
Computer program code for carrying out operations for
aspects of the present invention may be written in any com
bination of one or more programming languages, including
50
an object oriented programming language such as Java,
Smalltalk, C++ or the like and conventional procedural pro
discussed above.
55
computer, as a stand-alone software package, partly on the
user’s computer and partly on a remote computer or entirely
on the remote computer or server. In the latter scenario, the
remote computer may be connected to the user’s computer
through any type of network, including a local area network
Such a method may be implemented, for example, by oper
ating a computer, as embodied by a digital data processing
apparatus, to execute a sequence of machine-readable
instructions. These instructions may reside in various types of
signal-bearing media.
Thus, this aspect of the present invention is directed to a
60
programmed product, including signal-bearing media tangi
bly embodying a program of machine-readable instructions
executable by a digital data processor to perform the above
method.
Such a method may be implemented, for example, by oper
(LAN) or a wide area network (WAN), or the connection may
be made to an external computer (for example, through the
Internet using an Internet Service Provider).
Aspects of the present invention are described below with
reference to ?owchart illustrations and/ or block diagrams of
mercially available from many sources.
In addition to the system described above, a different
aspect of the invention includes a computer-implemented
method for performing the above method. As an example, this
method may be implemented in the particular environment
gramming languages, such as the “C” programming language
or similar programming languages. The program code may
execute entirely on the user’s computer, partly on the user’s
play adapter 736 for connecting the bus 712 to a display
device 738 and/or printer 739. Further, an automated reader/
65
ating the CPU 710 to execute a sequence of machine-readable
methods, apparatus (systems) and computer program prod
instructions. These instructions may reside in various types of
ucts according to embodiments of the invention. It will be
signal bearing media.
US 8,479,131 B2
14
13
Thus, this aspect of the present invention is directed to a
any programs that will reside on a server or servers when the
programmed product, comprising signal-bearing media tan
process software is executed 801. If this is the case then the
servers that will contain the executables are identi?ed 909.
gibly embodying a program of machine-readable instructions
executable by a digital data processor incorporating the CPU
710 and hardware above, to perform the method of the inven
tion.
The ?owchart and block diagrams in the Figures illustrate
The process software for the server or servers is transferred
directly to the servers’ storage via FTP or some other protocol
or by copying though the use of a shared ?le system 910. The
process software is then installed on the servers 911.
Next, a determination is made on whether the process
the architecture, functionality, and operation of possible
implementations of systems, methods and computer program
products according to various embodiments of the present
software is be deployed by having users access the process
invention. In this regard, each block in the ?owchart or block
the process software on servers then the server addresses that
will store the process software are identi?ed 803.
A determination is made if a proxy server is to be built 900
to store the process software. A proxy server is a server that
software on a server or servers 802. If the users are to access
diagrams may represent a module, segment, or portion of
code, which comprises one or more executable instructions
for implementing the speci?ed logical function(s). It should
also be noted that, in some alternative implementations, the
sits between a client application, such as a Web browser, and
functions noted in the block may occur out of the order noted
a real server. It intercepts all requests to the real server to see
in the ?gures. For example, two blocks shown in succession
may, in fact, be executed substantially concurrently, or the
to the real server. The two primary bene?ts of a proxy server
if it can ful?ll the requests itself. If not, it forwards the request
blocks may sometimes be executed in the reverse order,
depending upon the functionality involved. It will also be
20
noted that each block of the block diagrams and/ or ?owchart
illustration, and combinations of blocks in the block diagrams
and/ or ?owchart illustration, can be implemented by special
purpose hardware-based systems that perform the speci?ed
functions or acts, or combinations of special purpose hard
ware and computer instructions.
be to send a transaction to the servers that contained the
25
Deployment Types include loading directly in the client,
server and proxy computers via loading a storage medium
such as a CD, DVD, etc. The process software may also be
automatically or semi-automatically deployed into a com
35
software is to be deployed by sending the process software to
will be deployed are identi?ed together with the addresses of
40
install the proxy server code on the proxy computer. The
process software will be transmitted to the proxy server then
45
While it is understood that the process software may be
deployed by manually loading directly in the client, server
and proxy computers via loading a storage medium such as a
CD, DVD, etc., the process software may also be automati
cally or semi-automatically deployed into a computer system
50
by sending the process software to a central server or a group
of central servers. The process software is then downloaded
into the client computers that will execute the process soft
ware. Alternatively the process software is sent directly to the
client system via e-mail. The process software is then either
detached to a directory or loaded into a directory by a button
on the e-mail that executes a program that detaches the pro
cess software into a directory. Another alternative is to send
the process software directly to a directory on the client
computer hard drive. When there are proxy servers, the pro
cess will, select the proxy server code, determine on which
such as File Transfer Protocol (FTP). The users access the
55
60
proxy computer. The process software will be transmitted to
process software. The ?rst thing is to determine if there are
directories on their client ?le systems in preparation for
installing the process software 908. The user executes the
program that installs the process software on his client com
computers to place the proxy servers’ code, transmit the
As shown in FIG. 9, Step 800 begins the deployment of the
the user client computers 805. The process software is sent via
e-mail to each of the users’ client computers. The users then
receive the e-mail 905 and then detach the process software
from the e-mail to a directory on their client computers 906.
The user executes the program that installs the process soft
ware on his client computer 912 then exits the process 808.
Lastly, a determination is made on whether to the process
software will be sent directly to user directories on their client
computers 806. If so, the user directories are identi?ed 807.
The process software is transferred directly to the user’ s client
computer directory 907. This can be done in several ways
such as but not limited to sharing of the ?le system directories
and then copying from the sender’ s ?le system to the recipient
user’s ?le system or alternatively using a transfer protocol
proxy server code, then install the proxy server code on the
the proxy server then stored on the proxy server.
each client computer. The user executes the program that
installs the process software on his client computer 912 then
exits the process 808.
In step 804 a determination is made whether the process
users via e-mail. The set of users where the process software
proxy servers’ code, transmit the proxy server code, then
stored on the proxy server.
systems 903. Another embodiment is to have the servers
automatically copy the process software to each client and
then run the installation program for the process software at
server or a group of central servers. The process software is
either detached to a directory or loaded into a directory by a
button on the e-mail that executes a program that detaches the
process software into a directory. Send the process software
directly to a directory on the client computer hard drive.
When there are proxy servers, the process will, select the
proxy server code, determine on which computers to place the
process software and have the server process the transaction,
then receive and copy the process software to the server’s ?le
system. Once the process software is stored at the servers, the
users via their client computers, then access the process soft
ware on the servers and copy to their client computers ?le
30
puter system by sending the process software to a central
then downloaded into the client computers that will execute
the process software. The process software is sent directly to
the client system via e-mail. The process software is then
are to improve performance and to ?lter requests. If a proxy
server is required then the proxy server is installed 901. The
process software is sent to the servers either via a protocol
such as FTP or it is copied directly from the source ?les to the
server ?les via ?le sharing 902. Another embodiment would
65
puter 912 then exits the process 808.
The process software which consists of is integrated into a
client, server and network environment by providing for the
process software to coexist with applications, operating sys
tems and network operating systems software and then
installing the process software on the clients and servers in the
environment where the process software will function.
The ?rst step is to identify any software on the clients and
servers including the network operating system where the
process software will be deployed that are required by the
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