presents
High-Speed High-Accuracy
3D VLSI Extraction
ICCAD99
1
Motivation
■
Interconnects Now Dominate VLSI
"
Timing
"
Signal Integrity
100
Gate
Delay [%]
80
Interconnect
60
40
20
0
0.5 µm 0.35 µm 0.25 µm 0.18 µm 0.13 µm
Process Technology
■
■
ICCAD99
Existing Interconnect Extractors Fail
"
Poor Accuracy & High Speed
"
Medium Accuracy & Very Low Speed
Need High-Speed High-Accuracy Extractor
2
Overview
■
Company
■
Technology
■
■
"
High-speed High-accuracy BEM 3D Field Solver
"
Efficient Net-by-Net RC Extraction
Products
"
Extraction of Critical Cells, Blocks, Nets
"
Distributed RC Models
"
IR drop
"
Substrate Coupling
Differentiation
"
■
ICCAD99
2D / 2.5D / 3D Tools
Summary
3
Coyote Systems
■
■
History
"
Privately held, located in San Francisco CA
"
Founded in July 1996 by 3D Field Solver & MEMS experts
"
DARPA contract to develop extremely fast & easy-to-use 3D CAD
for MEMS
Products
"
First MEMS product AutoMEMS® announced July 1998
"
First VLSI product AutoIC® announced June 1999
"
New Tools
- AutoIC® v2, AutoIC-SMP™, AutoNet™, AutoSubstrate™,
AutoIRdrop™, AutoMEMS® v2
■
ICCAD99
Customers
"
End-users include Siemens, Monterey, Analog Devices, Motorola,
Texas Instruments, Hewlett-Packard, Sandia, MIT, Berkeley, CMU
"
OEM licenses include Monterey Design
4
Company Mission
■
VLSI
Provide premium high-speed
high-accuracy solutions for
extraction, timing, and signal
integrity problems for modern
VLSI designs.
■
MEMS
Provide premium high-speed
high-accuracy analysis of large,
realistic MEMS devices.
ICCAD99
5
Coyote Products
■
■
■
ICCAD99
Technology
"
AutoBEM
Fastest BEM field solver
"
AutoBEM-SMP
Exploit fine-grained parallelism
on SMP computers
"
AutoIC
Capacitance extraction of interconnects
"
AutoIC-SMP
SMP support
"
AutoNet
Distributed RC models from layout
"
AutoSubstrate
Resistive coupling in substrate
"
AutoIRdrop
Potential drop in powergrid
VLSI
MEMS
"
AutoMEMS
Coupled electro/mechanical simulator
"
AutoMEMS-SMP
SMP support
6
VLSI Geometries
■
Interconnects dominate performance
■
Deep submicron is 3D
"
Huge layouts
"
Intricate topologies
"
ICCAD99
IBM
"
AMD
7
VLSI Extraction
■
■
RC Interconnect Extraction Tools
"
High-Speed
"
High-Throughput
"
High-Capacity
"
High-Accuracy
Possible Alternatives
"
3D Field Solvers
- Coyote Systems
"
Statistical Methods
- QuickCap™
"
Pattern Matchers
- Simplex
- Raphael™
- Frequency
- FastCap
- Mentor
- Ultima
■
ICCAD99
Identify Advantages/Disadvantages
8
Pattern Matchers
■
■
Why they are used
"
Mature technology, Very Fast
"
Requires 3D field solver to develop pattern library
2D/2.5D tools do not capture 3D DSM effects
"
Fast (<100,000 nets/hour) after
lengthy precharacterization (100-200 hours)
"
Increasing difficulties with modern processes
- Many Layers, small feature sizes
- Arbitrary angles & non-manhattan geometries
- PCB-style variable wire width
- Increasing number of patterns needed
ICCAD99
"
Optimistic “error cancellation” - no bounded errors
"
Large errors (>20%)
9
Accuracy Problem!
"
Some pattern matching vendors claim <<10% errors
"
Simple counterexample...
≠
3D Field Solver
ICCAD99
+
+
Pattern Matching
"
3D simulation reveals 20% errors using superpositioning!
"
Geometric non-linearities prevent accurate solutions
10
Statistical Methods
■
■
ICCAD99
Why are they sometimes used
"
Alternative to FEM, FDM
"
Reasonably good for Self-Cap & Small Problems
Why will they not solve the problem
"
No Distributed R’s & C’s
"
Very long run times with increasing number of nets
"
Inaccurate Coupling Capacitance - Cij
"
Only supports Manhattan Geometries
"
Expensive support for multiple dielectrics
"
Solves only part of the problem - Cii
11
Alternative Solvers
■
■
■
ICCAD99
Proposed Technologies
"
FEM
"
FDM
"
Traditional BEM
Why will they not solve the problem
"
Not fast enough
"
Limited to very small problems
"
Huge memory and CPU time requirements
Computationally not feasible
12
VLSI Extraction
■
Coyote combines advantages of all approaches!
"
Field solver accuracy
"
Pattern matcher speed & capacity
Accuracy
100
80
60
40
Coyote
Field solver
20
Pattern matcher
0
Capacity
ICCAD99
Speed
13
VLSI Geometries
■
Interconnects dominate performance
■
Deep submicron is 3D
"
High aspect ratios
"
Extreme Density
"
Round Corners
"
Cylindrical Vias
"
Variable width wires
"
Nonideal CrossSections
"
Coyote can verify the effect of all these features!
"
IBM
"
AMD
- Simplex, Frequency, Avanti, Mentor, QuickCap™ cannot
■
ICCAD99
3D problems require 3D solutions!
14
3D Field Solvers
■
Arbitrary Geometries
"
■
Arbitrary Materials
"
■
Neumann, Dirichlet, mixed, floating
Only Coyote’s AutoIC® solves everything!
"
ICCAD99
Planar & conformal dielectrics
Arbitrary Boundary Conditions
"
■
PCB-style, manhattan & non-manhattan
AutoIC is faster, more accurate, and easier to use!
15
3D Field Solvers
■
If field solver, then pick best field solver
"
Simplest, smallest model
"
Most accurate (states & gradients)
"
Fastest runtime
"
Lowest memory requirements
BEM
ICCAD99
FEM
Direct
Iterative
Multipole
Direct
Iterative
Nr. nodes
N^2
N^2
N^2
N^3
N^3
Memory
N^4
N^4
(NlogN)^2
N^6
N^4.5
CPUtime
N^6
N^4
(NlogN)^2
N^9
N^4.5
"
Coyote uses Multipole Accelerated BEM
"
Computational Scaling N^2 ➔ NlogN
16
AutoIC Field Solver
■
ICCAD99
VLSI Interconnect Extraction
"
Accelerated Boundary Element Method
"
Automatic meshed 3D model from 2D layout
"
Adaptive mesh refinement
"
Robust automation
"
Scriptable batch-mode or interactive GUI-mode operation
"
Superset of Sematech extraction API
"
Cluster & symmetric multiprocessing (SMP) support
17
AutoIC Speed
■
■
■
AutoIC™ 3D Field Solver
"
2,000,000 BEM elements/hour per cpu
"
1,500 nets/hour per cpu (user selected <2% error)
AutoIC vs. Field Solvers
"
10-50x faster than QuickCap™
"
100-500x faster than Raphael™
AutoIC vs. Library-based "Pattern Matchers"
"
Similar speed to Frequency
◆
Accuracy
●
◆
+2.93% to -4.93% with no outliers
Performance
●
Full accuracy / GDS mode :
500 nets /hour:
●
Full accuracy / LEF- DEF mode :
2500 nets/hour
●
“-fast” option (+/- 15% accuracy) :
6500 nets/hour
— 5 — 5/26/99 Copyright © 1999 by Frequency Technology, Inc. All rights reserved.
ICCAD99
18
AutoIC
■
ICCAD99
Best Performance
"
Faster than FastCap, QuickCap™, Raphael™, Space, etc.
"
As fast as pattern matchers!
"
Solves many more problems
"
Large savings replacing multiple licenses
"
Large engineering time savings
19
Customer Tests
■
■
ICCAD99
Motorola SRAM Evaluation
"
Self-cap Extraction
"
Cross-cap Extraction
"
Convergence
"
Time & Memory
"
Model Generation
"
Ease-of-Use
Motorola Compared
"
AutoIC™
"
QuickCap™
"
Raphael™
20
Motorola SRAM Cell
■
Convergence of bit-line self-capacitance
"
Require
better than
±5% accuracy
2.50E-15
■
AutoIC
"
"
"
10-100x
faster!
Capacitance [F]
2.00E-15
1.50E-15
AutoIC-constant
AutoIC-linear
1.00E-15
Raphael
Best
convergence!
Tight error
bounds!
QC 0.01u
QC 0.005u
105%
5.00E-16
95%
0.00E+00
1
10
100
1000
10000
cputime [sec] (AutoIC on 500MHz PentiumIII, others on 333MHz UltraII)
ICCAD99
21
Siemens Block
■
Extract Critical Nets
"
500 nets
"
1x1mm die
"
0.35um process
"
3 metal layers
"
Multiple dielectrics
■
ICCAD99
AutoIC results
"
<2% Errors
"
Excellent scaling
Extraction Time [sec]
60
40
7700um/min
20
0
0
2000
4000
6000
8000
Critical Net Length [um]
"
8mm/min extraction
"
All nets extracted in 20 min using 1 cpu = 1,500 nets/hour
"
All nets extracted in 1 min using 20 cpus = 30k nets/hour
22
Design Flow
■
Industry Std Layout
"
■
■
■
ICCAD99
GDSII, annotated GDSII, CIF, Sematech API
3D Model Generator
"
Flexible process descriptor
"
API-mode or Batch-mode or GUI-mode
3D RC Extraction
"
Lumped, distributed
"
API-mode or Batch-mode or GUI-mode
Industry Std Output
"
Spice, Sematech API
"
3D visualization
23
Model Generation
■
Input
"
Layout
"
Process Description
- Arbitrary layers
- Interlayer dielectrics
- Conformal dielectrics
■
Output
"
ICCAD99
Meshed 3D Model
24
Applications
■
■
■
Critical Cells
"
Coefficient generation
"
Cell optimization
Critical Blocks
"
IP characterization
"
Routing
Critical Nets
"
Clock trees, control lines
"
User-selected nets
■
Substrate Coupling
■
IR drop
"
ICCAD99
Power grid effects delays
25
Critical Cells
■
ICCAD99
AutoIC simulates 10,000 cells in 2 hours
"
1 AutoIC license replaces 50-200 Raphael™ licenses
"
Adaptive meshing on SRAM bit-line shown
26
Cell Optimization
■
AutoIC identifies where interactions occur
■
Modify layout to optimize performance
"
ICCAD99
Magnitude of electrostatic flux on SRAM bit-line shown
27
Critical Nets
■
ICCAD99
Handles largest global nets
"
Automatic tunneling around aggressor net
"
3D visualization indicates crosstalk areas
"
Designer can modify layout to eliminate problem
"
1 AutoIC license replaces 10-50 QuickCap™ licenses
28
Critical Blocks
■
ICCAD99
PCB-style layout (Cypress)
"
Non-manhattan Geometries
"
Varying Linewidths
"
AutoIC 500x faster than QuickCap™!
"
Aggressor net, 3D tunnel & 3D mesh shown
29
Non-Ideal Fabrication
■
■
ICCAD99
AutoIC simulates Process Variations
"
Any geometry
"
Any material
AutoIC correctly solves floating filler metal
"
Note that filler adds 20% to self-cap!
"
Non-zero potential on floating filler shown
30
AutoIC-SMP Scaling
■
Symmetric multiprocessing support
"
Excellent scaling with every added CPU
"
Accelerates both large and small nets
SMP Scaling for Critical Net Extraction
Relative Scaling
4
3
2
Large Monterey benchmark
global net (control90 !RESET)
small net (control90 !n6969)
1
1
2
3
4
Number CPUs (Sun Ultra Enterprise 450)
ICCAD99
31
"The Layout is the Design"
■
Timing Delay
"
■
■
■
Signal Integrity
"
“Noise” or “Crosstalk”
"
Cross-capacitances dominate
AutoIC generates lumped RC models
"
Extracts high-accuracy 3D self-caps and cross-caps from the
interconnect layout
"
3D visualization identifies areas for correction
AutoNet generates distributed RC models
"
ICCAD99
Self-capacitances dominate
Important differences between lumped and distributed
simulations
32
AutoNet
■
Go from Layout to Distributed Spice
■
Variable model size
"
"
Lumped net =
1 segment
Segment1
T1
B
Distributed net =
multiple segments
a
b
V2
T5
T4
D
T2
V3
■
Segments
"
C
Spice star-model for each
segment
Segment3
Segment1
T1
T3
V1
B
A
"
T3
V1
A
a
Created from layout
Segment4
V3
"
Cross-caps between segments
"
Compact Spice model size
"
No model reduction needed
C
T4
V2
D
T2
T5
Segment2
Segment5
b
ICCAD99
33
AutoNet
■
■
Automatic segmentation
"
5 segments on Net1
"
4 segments on Net2
Net2
Net1
Distributed RC spice model
"
Each segment has self-capacitance
"
Each segment has cross-capacitances to segments on other nets
B
A
C
D
c
d
E
d
A
B
C
a
b
D
c
E
a
ICCAD99
b
34
AutoNet
■
Parallel bus lines
Unit step response
1
"
Generated distributed model
(8 segments per net)
0.8
"
volts
0.6
Generated lumped T-model
(1 segment per net)
0.4
0.2
Vin
8 segments
T-model
0
0
0.1
0.2
0.3
0.4
0.5
time [ps]
0.6
0.7
0.8
0.9
1
0.9
1
Crosstalk
1
0.8
volts
0.6
0.4
Vin
8 segments
T-model
0.2
0
"
Step Response
0
0.1
0.2
0.3
0.4
0.5
time [ps]
0.6
0.7
0.8
- Distributed and T model responses similar
"
Coupling
- Distributed and lumped responses similar
ICCAD99
35
AutoNet
■
Non-uniform bus lines
Unit step responses
1
"
Generated distributed model
(4-5 segments per net)
0.8
0.6
Generated lumped T-model
(1 segment per net)
volts
"
0.4
Vin
4/5 segments
T-model
0.2
Victim B
0
0
0.1
0.2
0.3
0.4
Victim A
0.5
time [ps]
0.6
0.7
0.8
0.9
1
Crosstalk
1
Vin
Victim A, 4/5 segments
Victim B, 4/5 segments
Victim A, T-model
Victim B, T-model
0.8
volts
0.6
0.4
Aggressor
"
Step Response
0.2
0
0
0.1
0.2
0.3
0.4
0.5
time [ps]
0.6
0.7
0.8
0.9
1
- Distributed and T model responses similar
"
Coupling
- 2x more noise on distributed model
ICCAD99
36
AutoNet
■
Parallel lines with varying cross-section
"
Net1 switches
Unit step response and coupling effects
1.2
Net2
1
Net1
volts [V]
0.8
Vin
response, 4/5 segments
response, T-model
response, self capacitance
coupling, 4/5 segments
coupling, T-model
0.6
0.4
0.2
0
"
0
10
20
30
40
50
time [ps]
60
70
80
90
100
Step Response
- Distributed and T models similar
- Commonly used self-cap model is inaccurate
"
Coupling
- 30% larger noise with distributed model
ICCAD99
37
AutoNet
■
Non-uniform parallel lines
"
Nets switch in opposite directions
High/low switch response
Non-monotonic
1.2
Net2
1
Net1
volts [V]
0.8
Vin1
Vin
2
0.6
Vout1, 4/5 segments
Vout , T-model
1
Vout2, 4/5 segments
0.4
Vout , T-model
2
0.2
0
"
0
10
20
30
40
50
time [ps]
60
70
80
90
100
Step Response
- Distributed and T models similar
"
Coupling
- Distributed model shows non-monotonic behavior
ICCAD99
38
AutoNet
■
Clock Tree Skew
"
Hierarchical H-shaped layout
"
256 terminals
Clock skew
1
volts [V]
0.8
0.6
Vin
Vout1
Vout2
Vout3
0.4
0.2
0
0
20
40
60
sample segments
ICCAD99
80
100
time [ps]
120
"
RC model with 70 segments
"
Non-constant clock skew due to cross capacitances
"
20% clock skew at 3 random clock terminals!
140
160
180
200
39
AutoNet
■
Compare Floating Filler & Grounded Filler
"
3x3 crossing bus
"
Net1 switches
Unit step response, filler floating / grounded
1
0.8
volts [V]
Net1
Net2
0.6
Vin
Vout1, floating filler
Vout , grounded filler
1
0.4
Vout , floating filler
2
Net3
Vout , grounded filler
2
Vout3, floating filler
Vout3, grounded filler
0.2
0
■
ICCAD99
0
0.1
0.2
0.3
0.4
0.5
time [ps]
0.6
0.7
0.8
0.9
1
Significant filler problem
"
25% difference in risetime
"
9x increase in noise level
40
AutoIRdrop
■
AutoIC solves 3D field
outside interconnects
2
■
AutoIRdrop solves 2D/3D
field inside interconnects
1
3
■
"
Varying angles, width,
cross-section
"
Vias
"
Aluminum, copper
"
Current sink/source
4
2D/3D Field Solver
"
Solves potential drop
- Resistance
"
Solves current density
through wire
- Enables electromigration analysis
ICCAD99
41
AutoIRdrop
■
"Naive" Resistance Network
"
■
1
2
3
4
N-ports require N simulations,
resulting in N2 resistances
"Smart" Resistance Network
"
1
N-ports require N simulations,
resulting in N resistances
4
■
ICCAD99
Field Simulation
"
2D resistance is very accurate,
much faster than 3D
"
2D suitable for resistance,
3D suitable for capacitance
2
3
42
AutoSubstrate
■
Solves 3D field
inside substrates
"
Contacts
"
Multiple materials
8
9
5
2
7
6
3
4
1
10
■
ICCAD99
3D Field Solver
"
Solves potential
distribution
"
Solves electrostatic
flux distribution
"
Solves current
density through
contacts
43
AutoSubstrate
■
Resistance Network
"
Resistance calculated
from calculated current
densities
5
x 10
12
10
"
Resistor for every portport interaction
Automatic spice model
8
Ohm
"
6
4
2
0
1
2
3
4
5
6
7
8
9
10
Port
ICCAD99
1
2
3
4
5
6
7
8
9
10
Port
44
Shipping Now
■
■
■
ICCAD99
Fastest, Most accurate, Easiest to use
"
Replace multiple tools
"
Large engineering time savings
Licenses
"
End-user licenses
"
OEM, Embedded licenses
Available Now
"
Sun, Linux, HP platforms
"
Uniprocessor & SMP configurations
45
For More Information
■
http://www.coyotesystems.com
■
Contact
"
ICCAD99
Dr. Per Ljung
2740 Van Ness Ave. #210
San Francisco, CA 94109
(415) 346 4223 x12
[email protected]
47