University of Arizona’s Innovative Planarization Laboratory Meetings... · 2007. 6. 12. · Darren DeNardis Yasa Sampurno Hyosang ... Masano Sugiyama Deanna King Juan Weaver. Equipment

1

University of Arizona’s Innovative Planarization Laboratory

Prof. Ara Philipossian ([email protected])

Department of Chemical and Environmental Engineering

University of Arizona

Tucson, AZ 85721 USA

Mission Statement

Collaborate with world-class equipment suppliers,consumables suppliers, IC makers and

research centersto provide

novel planarization solutionsthrough advancement of

fundamental knowledge & educational methods

• Lubrication and wear … Coefficient of friction analysis and force spectroscopy• Fluid dynamics … Dual Emission UV-Induced Fluorescence imaging, residence time

analysis & vessel dispersion analysis• Fundamental pad, slurry and conditioner characterization & design• Thermal modeling• Post-planarization cleaning• Planarization & post-planarization cleaning equipment design

Research Thrusts & Sponsors

2001 2002 2003 2004

Degussa

Hitachi Chemical

JSR

Sandia National Labs

Fujimi

Isamu Koshiyama

Fujikoshi

Asahi Sunac

Showa Denko

NeopadCourtesy of Tufts University

Research Partners

• Intel Corporation … Research Partner• STMicroelectronics … Research Partner• Hitachi Limited … Research Partner

• Atofina … Research Partner• Pall Corporation … Research Partner

• Intelligent Planar Research Partner

• Tufts University … Research Partner• Saitama University … Research Partner

• Rodel … Pad supply• Cabot Microelectronics Slurry Supply• Freudenberg … Pad supply

Research Staff

• Visiting Professor … Toshiro Doi (6/03 to 6/05)

• Post-Doc … Yun Zhuang (7/03 to 7/06)

• Visiting Researcher … Daizo Ichikawa (9/03 to 12/05) … FujikoshiHiroshi Takahashi (2/04 to 12/04) … SDKYoshiyuki Seike (1/04 to 6/04) … Asahi Sunac

• Ph.D. Candidate … Jam SorooshianZhonglin LiDaniel Rosales-YeomansDarren DeNardisYasa SampurnoHyosang Lee

• B.S. Candidate … Masano SugiyamaDeanna King Juan Weaver

Equipment & Capabilities• Planarization Equipment

– 2 Speedfam-IPEC 372M polishers (200 mm)• RR & RRNU, defect density, SHR, dishing &

erosion• Temperature map (on the pad and under the

wafer)• Mean residence time and fluid dispersion• Wafer-pad fluid film thickness

• Post-Planarization Cleaning Equipment

– 1 LAM DSS-200 PVA brush scrubber (200 mm)– 1 Verteq spin-rinse dryer (up to 200 mm)– 1 Manual wet bench (up to 200 mm)

• High Pressure Micro Jet Pad Conditioner (Asahi Sunac)

• Slurry Regeneration & Recycling System (Pall)

High Pressure Micro Jet (HPMJ) Conditioner

Fan Angle

Diamond Conditioning HPMJ Conditioning

0.1

1

0.E+00 1.E-02 2.E-02 3.E-02

Sommerfeld Number

COF

HPMJ Conditioning … COF & RR Results

0

5

10

15

20

0 0.1 0.2 0.3

Average COF

K-P

r x 1

E14

(1/P

a)

0.0

0.1

0.2

0.3

0.4

Diamond HPMJ

CO

F

0.31 m/s 0.62 m/s 0.93 m/s

0.0

5.0

10.0

15.0

20.0

25.0

Diamond HPMJ

K-P

r x

1E14

(1/P

a)

0.31 m/s 0.62 m/s 0.93 m/s

Diamond

HPMJ

Slurry Regeneration and Recycling System

Platen

Slurry Capture Tub

Spent Slurry Reservoir

Pump & Filter

Slurry Spike

Chemical Spike

inactive

ILD Slurry Regeneration & Recycling

• Pad = Rodel IC-1000 ‘perforated’

• Conditioning– 100 grit diamond disk– 30 minutes with UPW

at 20 rpm and 30 per minute sweep frequency

• Slurry = Fujimi PL-4217 at 60 cc per min (12.5 weight percent)

• Wafer Type = 100-mm thermally grown SiO2

• Wafer Speed = 0.62 m/s

• Wafer Pressure = 6 PSI

100

1000

10000

100000

1000000

Fres

h

Byp

asse

d

Rec

ycle

= 1

Rec

ycle

= 3

Rec

ycle

= 5

Larg

e P

artic

le C

ount

s of

Effl

uent

Slu

rryUnfiltered

Filtered

0

1

2

3

Fres

h

Byp

asse

d

Rec

ycle

= 1

Rec

ycle

= 3

Rec

ycle

= 5

Met

al C

onte

nt (p

pm)

Unfiltered

Filtered

135

139

143

147

151

Fres

h

Bypa

ssed

Rec

ycle

= 1

Rec

ycle

= 3

Rec

ycle

= 5

Mea

n Ag

greg

ate

Size

(nm

)

Unfiltered

Filtered


Si

O

O

OH

OH

OH

HO

HO

HO

Si

Si

Si

O

O

AlHO OH

OHHO

Si

Si

Dehydration

Silica Abrasive

Silica Abrasive

Si

Si Si

Si

800

1000

1200

1400

1600

1800

Fres

h

Byp

asse

d

Rec

ycle

= 1

Rec

ycle

= 3

Rec

ycle

= 5

ILD

Rem

oval

Rat

e (A

ngst

rom

s pe

r min

ute)

Unf iltered

Filtered

0.10

0.15

0.20

0.25

Fres

h

Byp

asse

d

Rec

ycle

= 1

Rec

ycle

= 3

Rec

ycle

= 5

CO

F

Unfiltered

Filtered


900

1100

1300

1500

1700

135.0 140.0 145.0 150.0 155.0

Mean Aggregate Size (nm)IL

D R

R (A

/min

)

900

1100

1300

1500

1700

0.13 0.15 0.17 0.19 0.21 0.23

COF

ILD

RR

(A/m

in)

Analyzing Raw Frictional Data

40

• Typical Polish Run:– 75 seconds– 1000 frictional force measurements per

second– 75,000 data points per run

)()( tfFtF shearshear +=

γ = Interfacial Interaction Index γ = Area under the curveγ = Total amount of mechanical

energy caused by stick-slipγ = 7.51

Normal

Shearavg F

FCOF =

wafer, platen & conditioner kinematics

(0.5 to 2.4 Hz)

unique to k-groove pads related to distribution of collision events

between grooves & leading wafer edge (20 to 500 Hz) Tool vibration and

resonance

Fumed Silica Slurries

Primary Particle Size ~ 30 nmMean Aggregate Size ~ 110 nm

‘High’ degree of structure

Source: Degussa

Recycling & Filtration vs. Frictional ‘Fingerprint’

ReferenceFresh Slurry

Recycle = 1UNFILTERED

Recycle = 1FILTERED


Recycle = 3FILTERED




Recycle = 5FILTERED



Gamma vs. Removal Rate

750

1000

1250

1500

1750

2000

2250

0.00 0.50 1.00 1.50 2.00 2.50

Gamma

ILD

RR

(A/m

in)

Fresh

1 Recycle - Filtered



1 Recycle - Unfiltered



Equipment & Capabilities• Planarization & Post-Planarization Cleaning Equipment (continued)

– 3 Copy EXACTLY! custom-made polishers & tribometers (100 mm)• 1:2 scale of Speedfam-IPEC 472• COF, fluid film thickness analysis, RR & RRNU• Temperature map (on the pad and under the wafer)• Mean residence time and fluid dispersion• Pressure map

– 1 polisher & tribometer (200 mm)• Fujikoshi 200-mm polisher customized for copper & low-k applications (down to 0.2 PSI)• COF, fluid film thickness analysis, RR & RRNU• Thermal and pressure imaging• Mean residence time and fluid dispersion

– 1 Controlled-Atmosphere polisher (100 mm)• Fujikoshi 2nd prototype for polishing under controlled gaseous ambient as well as vacuum• RR, RRNU, defect density, SHR, dishing & erosion• Thermal imaging

– 1 custom-made PVA brush scrubber and tribometer (up to 200 mm)

200-mm Polisher & Tribometer for Cu & ULK

200-mm Polisher & Tribometer for Cu & ULK

24

25

26

27

28

29

30

31

32

0 15 30 45 60

Polish Time (sec)

Tempe

ratu

re (d

eg C

)

0.01

0.1

1

0.00001 0.0001 0.001 0.01 0.1

Sommerfeld Number

CO

F

IC-1000 XY-Groove

IC-1000 K-Groove

IC-1000 Flat

Wafer Temperature (C)

P x

V (K

pa-m

/s)

Experimental Conditions

• Constants:

– Conditioning• 100 grit diamond disc• 30 min with UPW at 30 rpm

disk speed and 20 per min sweep frequency

– Slurry• Fujimi PL-4217 at 12.5 weight

percent• 220 cc per minute

– Wafers• 200-mm in diameter• 7000 Angstrom thermal SiO2

on silicon

• Variables:

– Platen & wafer angular velocity (m/s)

• 0.31• 0.62• 0.93

– Wafer pressure (PSI)• 2 • 3 • 4

– Pad type• Rodel IC-10-A2

– Pad surface texture• K-groove

Lubrication Mechanism

0.01

0.10

1.00

1.0E-03 1.0E-02 1.0E-01

Sommerfeld Number

Ave

rage

CO

F

0.0E+00

5.0E-10

1.0E-09

1.5E-09

2.0E-09

2.5E-09

3.0E-09

3.5E-09

4.0E-09

4.5E-09

0.0E+00 5.0E+03 1.0E+04 1.5E+04 2.0E+04 2.5E+04 3.0E+04 3.5E+04

P x V (Pa-m/sec)

RR

(m/s

)200-mm Y-direction

200-mm X-direction

IC-1000 (100-mmIC-1400 (100-mm)

Spectral Analysis

• X direction

• Y direction

Gamma = 49.23

Gamma = 28.35

Controlled Atmosphere Polisher (CAP)

Post-CMP Cleaning Apparatus

0.25 PSI

0.35 PSI

0.45 PSI

0.58 PSI 0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

F

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

F

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

F

Mixed-to-Hydrodynamic Mainly Hydrodynamic Hydrodynamic

pH ~ 1.1 pH ~ 7.0 pH ~ 10.7

Equipment & Capabilities• Metrology Equipment

– Film thickness, dishing and erosion:• Insulators … Rudolph and Gaertner Ellipsometers (up to 200 mm)• Metals … Veeco resistivity mapping system (up to 200 mm)• Veeco stylus profilometer and KLA-Tencor P2 profiler (up to 200 mm)

– Defect density:• KLA-Tencor 7600 (patterned wafers) and KLA-Tencor 5500 (blanket wafers) defect

detection systems (up to 200 mm)

– Thermal and pressure mapping:• FLIR infrared camera (on loan from MIT)• Photometrics CCD cameras (also perform fluid film thickness measurements)• Tekscan pressure sensor (up to 200 mm)

– Pad and PVA brush mechanical characterization:• TA Instruments Thermo-Mechanical Analyzer, Dynamic Mechanical Analyzer and

Dynamic Scanning Calorimeter• Pad Flattening Ratio (PFR) analyzer

– Slurry characterization:• TA Instruments rheometer (up to 50,000 1/sec)

Pad Characterization

Normal

Shearavg F

FCOF =

ShearNormalavg FFCOF =×

PFNormal ∝

Shearavg FPCOF ∝×

Low-k

Cu

Low-k

~ 3.5 PSI ~ 0.7 PSI ~ 0.1 PSI

ULK Delamination during Copper CMP

The photograph below and the SEM micrograph are courtesy of Hitachi Chemical

Novel Pad Groove Designs

Flat padLogarithmic Spiral NegativeLemniscate Logarithmic Spiral Positive

Novel Pad Groove Designs

0.0

0.1

0.2

0.3

0.4

0.5

Log Spiral Neg Log Spiral Pos Flat Lemniscate

Ave

rage

CO

F

0.10

1.00

1.00E-03 1.00E-02 1.00E-01

Sommerfeld Number

Ave

rage

CO

F

Logarithimic-Spiral-Negative

Logarithimic-Spiral-Positive

Flat

Lemniscate

0.001

0.01

0.1

1

1.0E

-03

1.0E

-02

1.0E

-01

1.0E

+00

Sommerfeld Number (unitless)

Coe

ffici

ent o

f Fric

tion

(uni

tless

)

Analyzing Raw Frictional Data• Typical Polish Run:

– 75 seconds– 1000 frictional force

measurements per second– 75,000 data points per run

)()( tfFtF shearshear +=

γ = Interfacial Interaction Index γ = Area under the curveγ = Total amount of mechanical

energy caused by stick-slipγ = 7.51

Normal

Shearavg F

FCOF =

wafer, platen & conditioner kinematics

(0.5 to 2.4 Hz)

unique to k-groove pads related to distribution of collision events

between grooves & leading wafer edge (20 to 500 Hz) Tool vibration and

resonance

CMP and The Violin

Time

Bow

Spe

edTime

Strin

g Sp

eed

Waveforms in Time and Frequency Domains

2 PSI & 0.93 m/s

6 PSI & 0.93 m/s

Force Spectra

Lemniscate Gamma =

43.26

Flat Gamma = 2.09

Logarithmic Spiral Negative Gamma = 10.01

Logarithmic Spiral Positive Gamma = 5.34

Minimum Sommerfeld Number (6 PSI & 0.31 m/s)

Maximum Sommerfeld Number (2 PSI & 0.93 m/s)

Lemniscate Gamma =4.80

Flat Gamma = 1.46

Logarithmic Spiral Negative Gamma = 24.79

Logarithmic Spiral Positive Gamma = 7.88

*

*

* *

Post-Planarization PVA Brush Scrubbing

• For PVA scrubbers with simple kinematics, Stribeck curves have been used to determine the lubrication mechanism and have helped predict brush life, however:

– Experimentally intensive– Inherent uncertainty in estimating the

constituents of the Sommerfeld number

• Fluid film thickness in the brush-wafer interface

– Nodules– Mechanical properties of the polymer

• Localized brush pressure as a function of brush deformation

– Completely misleading when complex kinematics are involved

0.25 PSI

0.35 PSI

0.45 PSI

0.58 PSI

Goals• Determine whether spectral analysis based on raw frictional data

obtained during PVA brush scrubbing:

– Can shed light on the tribology of the process as a function of: • Brush rotational velocity and oscillation frequency• Wafer velocity• Solution pH • Brush pressure

– Can help ‘fingerprint’ the process and help in:

• New endpoint detection methods• Process, consumables and equipment diagnostics• Elucidation of fundamental physical and chemical phenomena taking place

during scrubbing

Brush rotation = 10 to 60 RPMBrush oscillation = 0 per minute

Wafer Rotation = 0 RPMP = 0.25 PSI

Stribeck Curves Corresponding to Simple Tool Kinematics (i.e. Brush Rotation Only)

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

F

pH = 1.1

pH = 10.7

pH = 7.0

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

F



0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

F




Wafer Rotation = 0 RPM

Stribeck Curves Corresponding to Complex Tool Kinematics

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

F

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

F

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

CO

FBrush rotation = 10 to 60 RPM

Brush oscillation = 20 per minuteWafer Rotation = 0 RPM



pH = 1.1

pH = 10.7

pH = 7.0

0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma

Gamma Curves Corresponding to Simple Tool Kinematics

0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma

0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma







pH = 1.1

pH = 10.7

pH = 7.0

0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma

‘Gamma Criterion’ for Determining the Likely Lubrication Regime

0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma

0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma

Gamma > 0.001 … Boundary Lubrication

0.0001 > Gamma > 0.001 … Partial Lubrication

Gamma < 0.0001 … Hydrodynamic Lubrication

Time Domain & Frequency Domain Spectra(pH = 1.1 and Pressure 0.35 PSI)

Brush rotation = 30 RPMBrush oscillation = 0 per minute






0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma

0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma

0.00001

0.0001

0.001

0.01

0.1

1

1.00E-06 1.00E-05 1.00E-04

Sommerfeld Number

Gam

ma







pH = 1.1

pH = 10.7

pH = 7.0

Gamma Curves Corresponding to Complex Tool Kinematics

Documents

University of Arizona’s Innovative Planarization Laboratory Meetings... · 2007. 6. 12. · Darren DeNardis Yasa Sampurno Hyosang ... Masano Sugiyama Deanna King Juan Weaver. Equipment