Upload
others
View
23
Download
3
Embed Size (px)
Citation preview
Optimum Inductor, Capacitor and Transformer Synthesis using EMX and
Continuum
Integrand Software, Inc.www.integrandsoftware.com
UMCJun Hong Ou Ji Wei Hsu Tim Cheng David Chen Lidia Chen Yi Jun Hong Ou, Ji-Wei Hsu, Tim Cheng, David Chen, Lidia Chen, Yi
Ju Wu, Anderson Huang, Yanan Mou, Jacky Zhang, Bigchoug Hung, Victor Liang, David Chen, Zheng Zeng, L.C.Yeh
Public Presentation at UMC booth June 12 2008
Collaboration between UMC and Integrandg
Created industry-first RF/Analog design environment for optimal component designp p g
Scalable component libraries (130nm, 90nm, 65nm)• Planar, symmetric and center-tapped inductors (with PGS)
S l bl MOM it (RF d Mi d M d )• Scalable MOM capacitors (RF and Mixed Mode)
• Baluns and Transformers
— Optimum Inductor Finder (OIF)
— Optimum Capacitor Finder (OCF)
— Optimum Transformer Finder (OTF)
Layout and synthesis within UMC’s FDKLayout and synthesis within UMC s FDK• Uses scalable models of capacitors and inductors
• Fully integrated within Virtuoso® environment
DAC 2008 2
EMX integrated within FDK for custom designs
CICC 07 paper on Integrated IC balunsp p g
Integrand and UMC have published a paper at CICC p p p2007 titled “Optimal Synthesis of On-Chip Baluns”
Industry first demonstration of high quality on chip IC baluns.
DAC 2008 3
EMX: “Software Network Analyzer”y
GDSWafer Process Tech File
EMXNetwork Analyzer De-embedding
Same mask GDSII layout used for wafer fabrication
DAC 2008 4
EMX vs UMC Measand EM simulation
EMX
Electromagnetic simulation• Simulation engine for analysis of various passive structures• Simulation engine for analysis of various passive structures
EMX is extremely fast and accurate— More than 10X faster than other commercial simulators
Proven silicon accuracy for a very large set of UMC designs
• inductors
• capacitors
• transformers
• components+interconnect• components+interconnect
DAC 2008 5
EMX for UMC structures
Physical Effects on ICsInductor
Physical Effects on ICs• R,L,C and Substrate effects unified and fully
coupled
Super-fast Simulation MOM capacitor
• A few minutes for an inductor or a capacitor
User friendly• Processing “true” layout for UMC
capacitor
slotting rules, via arrays, metal fill, and metal biasing for capacitors
Integrated within UMC’s FDK GUITransformer
DAC 2008 6
Automated synthesis via scalable modelsy
Inductors
• 4 types of inductor layouts
• Planar, Symmetric, Sym CT, stacked
• Optimize for L and Q
Capacitors
• 4 types (array and mesh with and without ground shieldand without ground shield
• Optimize C and Q
T f B lTransformers, Baluns
• 1 type with 4 types of center-tapping
• Optimize L Q Insertion loss
DAC 2008 7Scalable Model
• Optimize L, Q, Insertion loss
Layout
The Optimum transformer finder (OTF)p ( )
Baluns and transformers are important components of RF devices like mobile phones, wireless devices. Used for converting single-
d d t diff ti l i l ended to differential signal
UMC and Integrand have collaborated to build transformers and baluns on a 90nm process
Ceramic Baluns (e g Murata TDK)Ceramic Baluns (e.g., Murata, TDK)• Insertion loss: 1 – 1.5 dB
• Phase Imbalance: 10 degrees
• Amplitude Imbalance: 0.5dBAmplitude Imbalance: 0.5dB
• Large Area (2mm x 1.2mm)
• Off-Chip, large variation and low yield
UMC Baluns• Insertion Loss: 1 - 1.5 dB
• Phase Imbalance: < 0.25 degrees
• Amplitude Imbalance: < 0.1dB
DAC 2008 8
• Small Area (300um x 300um)
• On-Chip, low variation, high yield, high performance, high integration
EMX vs Measurement for transformers
DAC 2008 9
Design Space and of Transformersg p
Design Spacent_in: 1 to 9 turnsnt_innt_out: 1 to 9 turnsturns ratio: 1:1, 1:2, 1:3, 1:4w: 3 to 12 µms: 2um µm
ws: 2um µmod: 75 to 300 µmf: DC to 20 GHznt_out
od
DAC 2008 10
scalable model
Inductance Mode (Forward)( )
1. Select mode
2 Type in Geometric 2. Type in Geometric Parameters
3. Obtain Electrical ParametersParameters
DAC 2008 11
Inductance Mode (design)( g )
4) Give Electrical Parameters• Give L1 inductance
• Give a range for L2
• Bandwidth? Delta?
5) Obtain Geometric Parameters of an optimal transformer
OTF automatically minimizes the area?
DAC 2008 12
Inductance Mode (plot)(p )
plot
DAC 2008 13
Losses Mode
This is the mode that most designers will use the OTF.In this mode the designer specifies the input and output In this mode the designer specifies the input and output impedances, e.g.,
• Input impedance of package
• Output impedance of driverOutput impedance of driver
The OTF then finds • the optimum transformer
• associated tuning MiM capacitors that will satisfy the loss • associated tuning MiM capacitors that will satisfy the loss constraints
The most important design is a balun which has a single-ended input and a differential outputended input and a differential output
• Example using L_Transformer_ctout_RFVIL
• Primary is not center-tapped
• Secondary is center tapped
DAC 2008 14
• Secondary is center-tapped
Designing an 802.11B balun(2.5GHz) using losses mode( ) g
Design a single-ended to differential balun with center-tapped output using the following constraints
• 50 Ohms input impedance
• 200 Ohms output impedance
• Minimum insertion loss of –1dB
• Maximum return loss of –10dBMaximum return loss of 10dB
OTF determines
• Balun geometry
I t d O t t MiM it • Input and Output MiM capacitor values to tune the balun
• Minimize area (including MiM area)
DAC 2008 15
Plotting insertion and return lossesg
DAC 2008 16
Schematics for 4 types of transformersyp
DAC 2008 17
Balun silicon verification (Insertion Loss)( )
DAC 2008 18
Phase and Amplitude imbalancep
DAC 2008 19
LKQ plotsQ p
DAC 2008 20
LKQ plotsQ p
DAC 2008 21
New Advanced model features
Advanced features have been added to the scalable models for UMC
These new features were based on measurements• The models now include temperature dependence
Th d l i l d th bilit t h dl M t C l • The models include the ability to handle Monte-Carlo statistics on process variation
DAC 2008 22
Temperature coefficient extractionp
Temp coefficient=(percent change in resistance)/degree
StructureTemperature coefficient
IND905 0.46
IND914 0.48
IND916 0 54IND916 0.54
Pure copper (theory) 0.4
Temperature coefficients extracted from Inductor measurements
DAC 2008 23
measurements
Temperature dependence in EMX: IND905p p
DAC 2008 24
Monte-carlo statistics
Inter-wafer statistical variation was studied
DAC 2008 25
Monte-carlo scalable model results
Monte-carlo statistics extracted from the measurements has been included in the scalable the scalable models
L Q
DAC 2008 26
Summaryy
Successful and ongoing collaboration between UMC and Integrand Software Inc.
• OIF (Inductors with and without PGS)( )
• OCF (Capacitors for RF and Mixed-mode applications)
• OTF (Transformers and Baluns)
E t d d th f ti lit f UMC’ FDKExtended the functionality of UMC’s FDK• Process variation effects in scalable models
• Temperature dependence in models
• Capacitor Mismatch
DAC 2008 27
Extra Slides
DAC 2008 28
Inductors: EMX Simulation vs. Measurement
DAC 2008 29
MOM Capacitorsp
UMC MOM capacitors are accurately simulated by EMX
Need true 3D simulation Need true 3D simulation capabilities to handle metal sidewall and via sidewall capacitance
EMX automatically handles vias, metal bias that can affect the capacitance valuep
DAC 2008 30
MOM Capacitors: EMX Simulation vs. Measurement
DAC 2008 31
Scalable Component Modelsp
“Scalable” Models of Inductors and Capacitors
sp
• Spice models parameterized by geometry
• Critical for foundry model
ntCritical for foundry model libraries
• Created using EMX and Continuum
wod
array
nf
DAC 2008 32
lenstack
Design Space of Inductorsg p
ods
nt wnt
sfw
Design Space
od
Design Spacent: 1.5 to 7.5 turnsw: 3 to 10 µms: 1.5 to 5 µmd 75 300 )(32
),,,(21),,,(1
sntodwfRsubsntodwfCsub
sntodwfLc
==
=
DAC 2008 33
od: 75 to 300 µmf: DC to 20 GHz
...
...),,,(32 sntodwfRsub =
Design Space of Capacitorsg p p
arrayarray
nf len
f
nf
stackflenstack
Design Spacenf: 7 to 101 fingersMetal stack: 3 to 6 layersl th 5 t 25
DAC 2008 34
length: 5 to 25 µmarray: 1 to 4xf: DC to 20 GHz
EMX-Continuum™
Scalable Model Generator Design Spacent: 1.5 to 7.5 turns
• Discretization of space
• Built from 1000s of individual component (inductor or capacitor) simulations
W: 3 to 10 µmS: 1.5 to 5 µmOD: 75 to 300 µm
capacitor) simulations
• EMX as simulation engine
• Proprietary techniques used to develop “unified” model
Layout generator(UMC Cadence PCELL)
develop unified model
• Pure RLCK Spice
• Passive by construction EMX-Continuum• Noise analysis correct
Spice ModelsSpectre Eldo Hspice ADS
DAC 2008 35
Spectre, Eldo, Hspice, ADS
The Optimum Inductor Finder (OIF)p ( )
Design Space Optimization
• Finding optimal inductor Finding optimal inductor design
• Using the scalable spice models
• Almost instantaneous playback (5~10 seconds)
• GUI interface in Cadence Virtuoso
Optimizations
• Maximize Q
• Minimize Area
• Bandwidth optimizations
• Including PGS
DAC 2008 36
• Including PGS
Optimal Inductor Design for UWBp g
bac
Bandwidth
Trading Q for consistent inductance over wide bandwidth
DAC 2008 37
The goal of UWB design is to “flatten the inductance”
Typical Model Accuracyyp y
DAC 2008 38
PGS Designg
PGS capabilities added
Patterned ground plane Patterned ground plane shields substrate
Can increase Q by 30%
3 PGS d l ( l 3 PGS models (planar, symmetric, center-tapped) added to the UMC FDK
DAC 2008 39
PGSno PGS
UMC’s FDK with the Optimum Inductor Finder
OIF
DAC 2008 40Symbol ViewLayout View Scalable Spice Model
Optimum Capacitor Finder (OCF)p p ( )
Determine optimal capacitor Determine optimal capacitor design based on a number of tradeoffs:
• AreaArea
• Q
• Space/Shape Constraints
Metal Stacks• Metal Stacks
Single-ended or Differential Design
DAC 2008 41
OCF for RF Applicationspp
plotting
DAC 2008 42layout schematic
4 Mixed-mode Capacitors p
DAC 2008 43
Common Centroid Design of Capaitorsg p
centroid
Common Centroid Design minimizes the effect of mismatch
DAC 2008 44
Common Centroid Design minimizes the effect of mismatch
EMX direct interface to UMC’s Design Kitg
It is possible to directly access EMX through the UMC FDK (in Virtuoso®)
Allows designers to design components not contained in UMC library
Simulation of components and surrounding interconnects
(proximity effects)
Use the EMX menu to start the
DAC 2008 45
Use the EMX menu to start the simulation window
EMX interface
DAC 2008 46