Presentation - New Methodology for Spiral Inductor …electronica.ugr.es/.../New_Methodology_for_Spiral_Inductor_Design.pdfNew Methodology for Spiral Inductor Design Albert Yen UMC

New Methodology for Spiral Inductor Design

Albert Yen

UMC

Outline

n Introductionn Inductor Library from Foundryn Customer Request on Inductorn EM Design Methodology for Inductorn Results and Comparisonn Other Application using EMDMn Conclusion

On-Chip Spirals

RF Balun

BPF

Spiral Inductor

Ideal Circular Inductor

D

D+W

+S

W

S

N=4.5GND

Diffusion Dummy Block

Metal 5 Metal 6

Port1 Port2D

D+W

+S

W

S

N=4.5GND

Diffusion Dummy Block

Metal 5 Metal 6

Port1 Port2

Geometrical Parameter

Diameter

Number of Turn

Width of Trace

Space between Trace

Inductor Equivalent Model

Ls

Cp

Port1 Port2

Rs

Cox1 Cox2

Rsub1 Rsub2Csub1 Csub2

Spiral in CMOSn Sheet resistance of metal layer can be used only for

calculating the DC resistance of the spiral.n Due to the skin effect, eddy current and “current

crowding”, the resistance of the spiral increases at high frequency.

n Copper metal and thick top-level metal to improve the maximum inductor Q.

n Multiple levels of metal strapped together to create a spiral with a lower dc resistance.

n PGS: pattern ground shield reduce the substrate lossn CMOS substrate losses still the limiting factor

Outline

n Introductionn Inductor Library from Foundryn Customer Request on Inductorn Inductor Design Methodology {EMDM}n Results and Comparisonn Other Application using EMDMn Conclusion

Foundry’s Inductor Model and Library

n Empirical formulan Direct measured inductor libraryn Scalable model inductor library

Empirical Formula

OD

davg

dtrace

Wavg

trace

dd

=ρ

Empirical Formula

n : number of turns.

µ : permeability of free space

davg: average diameter

: percentage of the inductor area that is filled by metal traces.

++

= 2

2

125.0178.0067.2

ln2

ρρρπ

µ avgdnL

ρ

Measured Inductor Library

n Library dimension factorynRadiusnNumber of turnsnWidth of Trace

n Square Spiraln Circular Spiraln Ind_C1 to Ind_C20n L: 0.98 ~25(nH)n Q: 16 ~ 3.6 (5.6GHz), 10 ~ 7 (2.4G)

Scalable Inductance v.s. radius

Scalable Inductance v.s. turns

Outline


Various Spiral

?

Differential Spiral

?

Balance Spiral

Stack Balance Spiral

More Inductor Lib?

n Shape: Square, Octagonal Inductor, Circular Inductor

n Single end or Balance Inductor

How to support customer’s innovative inductor design?

n Provide measured inductor library.n Provide scalable Pcell library.n Why design engineer still need to struggle

through design test structure, measure data and modeling than re_spin test structure, measure data then calibrate the model again,…….

UMC’s innovative Approach

n In addition to existed tested, scalable library and model

n We provide extra ----

n An “methodology” that include process related information for EM software simulator, then customer can design innovative inductor with accuracy!

n Save prototype/test cycle timen Reduce R&D cost

Ansoft HFSS

n Current Version 9.0

n A true 3D Electromagnetic-Based Design Tool

n Widely used in Package, Wave guide and Antenna

n UMC is the first Foundry that provide the methodology for using 3D EM design tool to support RFIC design

UMC’s New Approach (1) - What is Our Purpose?

ØGeneral Inductor Design

With Si measurement data

3-D EM simulation data

+ RF SPICE model

3-D EM simulation interpolation for S parameter

3-D EM simulation extrapolation for S parameter Parameter 1

Param

eter 2

Inductor Pool

Parameters : Xo; W; S & N

Ø Special Inductor Design

Novel Inductor Design 3-D EM simulation S-Parameter Designer

Pattern shielding ground Transformer or stacked or others

UMC’s New Approach (2) - What is Our Purpose?

UMC’s New Approach (3)

Technology profile

SiO2 ε

Si

M1M22

M3

Testkey Layout

3-D EM Simulation Circuit SimulationS-Parameter

WaferFabrication

ICCAP

Model

ExtractionUMC Process

Work Flow

RF SPICEModel

Ansoft HFSSAnsoft HFSS

Ansoft Designer

UMC’s New Approach (4)- What is Technology File?

Silicon Thickness

M5 Thickness

SiO2 Thickness

M6 Thickness

Passivation Thickness

εrConductivity

εr

εr

Top Metal

Second Top Metal

εr

SiO2 Thickness

UMC’s New Approach (5)- What is Technology File?

Note: This unique technology file has been proved by comparing the simulation data with real Silicon measured data.

Material Physic Param SourceSubstrate T.K, Rs EDR, SEMSTI T.K, Dielectrics EDR, SEM M1~6 T.K, Rs EDR, SEM ILD/IMD1~5 T.K, Dielectrics EDR, SEMPassivation T.K, Dielectrics EDR, SEM

Ansoft HFSS: Spiral Inductor Macros

EMDM Inductor Design Flow

Only need to input design parameter:N TurnsW WidthS SpacingT Top Metal thicknessThen chose: Segments, Hextangle , Octangle, Circular

Operation Interface

n It is friendly to user that just only key in inductor’s parameter;Overall Dimension, Width, Spacing, Turns & Thickness

Current Status

n Success develop an unique technology file to represent UMC’s process used in Ansoft HFSS EM simulation.

n Process: 0.18um Logic 1P6M process with 20KA and 30kA Al top thick Metal.

n Valid Frequency Range: Simulation & Measurement sweep frequency: 0.6GHz~20.6GHz

Current Status

Ø For general Inductor design, both real Silicon measurement data and 3-D simulation data are used in the model extraction.

Ø Combining these two groups of raw data, we can extract RF SPICE model with higher accuracy.

ØThe technology file used in here can be faithfully represents Silicon process parameter.

Ø Based on the calibrated technology file, designers can implement novel idea, then obtain S-parameter for circuit simulation.

Outline


W (um) S(um) Turns Inner-Diameter(um) Thickness(KA)6 2 1.5 126 20" " " " "6 2 1.5 238 20" " " " "

10 2 1.5 85 20" " " " "" " " " "

10 2 2.5 85 20" " " " "

10 2 3.5 85 20" " " " "

10 2 4.5 85 20" " " " "

10 2 5.5 85 20" " " " "" " " " "

15 2 3.5 85 20" " " " "

15 2 3.5 150 20" " " " "

15 2 3.5 230 20" " " " "" " " " "

20 2 4.5 236 2020 2 5.5 236 20

Results and Discussion (1)- Device Sampling

Ø Group1=> Ø Scale Number of

Turns

Ø Group2=> Ø Scale Inner

Diameter

Results and Discussion (2)- Inductor Simulation Profile

Port2

Port1

Ø 3-D design environment, substrate effect can be included.

Results and Discussion (3)- Current flow showing

Ø Current flow @ 5.8GHz

Results and Discussion (4) - E&M field showing

Mag of Electric field @ 5.8GHz Mag of Magnetic field @ 5.8GHz

Results and Discussion (5) - E&M field showing

Vector of Electric field @ 5.8GHz

Vector of Magnetic field @ 5.8GHz

0.18-micro 1P6M Inductor N=5.5 comparison

-4

-2

0

2

4

6

8

10

0 1 10 100Frequency[GHz]

Qu

alit

y F

acto

r

0

2

4

6

8

10

12

14

Ind

uct

ance

[nH

]

N5.5_s_QN5.5_m_QN5.5_s_LN5.5_m_L

Results and Discussion (6)- L/Q simulation&measurement

comparison

Ø Width=10µm, Spacing=2µm, Di= 85µm, Turns=5.5, Al=20KA


-4

-2

0

2

4

6

8

10


Qu

alit

y F

acto

r

0

2

4

6

8

10

12

14

Ind

uct

ance

[nH

]

N4.5_s_Q

N4.5_m_Q

N4.5_s_L

N4.5_m_L


Results and Discussion (7)- L/Q comparison


-2

0

2

4

6

8

10

12

14


Qu

alit

y F

acto

r

0

1

2

3

4

5

6

7

8

Ind

uct

ance

[nH

]

N3.5_s_Q

N3.5_m_Q

N3.5_s_L

N3.5_m_L




0

2

4

6

8

10

12

14

16


Qu

alit

y F

acto

r

0

1

2

3

4

5

6

7

8

Ind

uct

ance

[nH

]

N2.5_s_Q

N2.5_m_Q

N2.5_s_L

N2.5_m_L




0

3

6

9

12

15

18

21

24


Qu

alit

y F

acto

r

0

1

2

3

4

5

6

7

8

Ind

uct

ance

[nH

]

N1.5_s_Q

N1.5_m_QN1.5_s_L

N1.5_m_L



0.18-micro 1P6M Inductance/diff diametercomparison

-1

0

1

2

3

45

6

7

8

9

10


Ind

uct

ance

[nH

]

D150_s_LD 85_s_LD150_m_LD 85_m_LD230_s_LD230_m_L

Results and Discussion (11) - Simulation & Measurement comparison

Ø Fixed width=15µm, spacing=2µm, Turns=2.5 & Al=20KA, variable Di: 85µm, 150µm and 230µm

Ø Good agreement with inductance.

0.18-micro 1P6M Inductor Case1 comparison

-4

-2

0

2

4

6

8

10

12

14


Qua

lity

Fact

or

1

2

3

4

5

6

7

8

9

10

Indu

ctan

ce[n

H]

Q_simulation

Q_measurement

L_simulationL_measurement

Results and Discussion (12) - Inductance & Q-value Comparison - (Case1)

Ø Simulation: Qmax = 10.35 @ 4GHz, Fsr=14.2GHz.Ø Measurement: Qmax = 10.8 @ 3.8GHz, Fsr=14GHz.

W:15um, S:2um, D:202um, N:2p5, AL:30K

0.18-micro 1P6M Inductor Case2 comparison

-6

-4

-2

0

2

4

6

8

10

12


Qua

lity

Fact

or

3

6

9

12

15

18

21

24

27

30

Indu

ctan

ce[n

H]

Q_simulationQ_measurement

L_simulationL_measurement

Ø Simulation: Qmax = 8.57 @ 1.4GHz, Fsr=6.2GHz.Ø Measurement: Qmax = 8.1 @ 1.4GHz, Fsr=6.4GHz.

Results and Discussion (13) - Inductance & Q-value Comparison (Case2)

- W: 6um, S:2um, D:210um, N:5p5, AL:30K

Results and Discussion (14) - Deep-trench pattern--case3

Ø Use Deep-trench to reduce substrate loss.Ø Deep-trench Side Cross Section.

Results and Discussion (15) - Deep-trench pattern--case3

0.18-micro 1P6M Inductor with Deeptrenchcomparison

-4

-2

0

2

4

6

8

10

12

14

16


Qu

alit

y F

acto

r

0

1

2

3

4

5

6

7

8

9

10

Ind

uct

ance

[nH

]

DT_s_Q

DT_m_Q

DT_s_L

DT_m_L

Outline


EMDM Flow

Ansoft HFSSwith Optimetrics

AnsoftLinks

Macros

DXF

ACIS

GDSII

Ansoft Designer

Virtuoso

Matrix ParametersS-, Y-, Z-

Results:Inductance

Quality FactorSelf-Resonance

etc

UMC Technology

File

PowerPlugin

AnsoftLink for Virtuoso

Easier than

Cut & Paste

Other Use of HFSS in IC design

n With UMC EMDM:n Model extraction on Interconnectionn Cross Talk analysis in RF or High Speed Digital ICn Capacitor: MIM, MOM (fringing)n Package Modeling for the IC Designn Internal Antenna Designn EM analysis RFIC with PCB

Outline


Conclusion

n Customer’s success is always our first goaln The RF design support is enhanced by providing an

accurate, efficient methodology for inductor library development.

n EMDM can be extended to use in much general high frequency analysis base on the same unique tech file.

n Reduce develop cycle time and cost, customer can go into production much faster.

n UMC is always seeking a better, improved service for our customer

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Presentation - New Methodology for Spiral Inductor …electronica.ugr.es/.../New_Methodology_for_Spiral_Inductor_Design.pdfNew Methodology for Spiral Inductor Design Albert Yen UMC