Innovation in ILD Polishing: Ultra-Low Defects and Reduced CoO · High Purity (no KOH) Rate Control Additives < 0.50% pH ~ 11 KOH 12.5% Fumed Silica Mechanism Balanced Chemical &

© 2005 Cabot Microelectronics Corporation

1

Innovation in ILD Polishing:Ultra-Low Defects andReduced CoO

June 2005


2

Discussion Topics

• Dielectrics Polishing Needs – Why Ceria?• General Polish Mechanisms• Factors Contributing to Cost of Consumables• Polishing Results

– Defects– Planarization

• Summary


3

Dielectrics Polishing Needs:iDiel™6600 Solution Development

• Market Needs (ILD)– Low Cost of Consumable per wafer

– Ultra-Low defectivity

– Similar Performance to Traditional Silica Based Slurries in Other Areas

– Stable, Predictable Performance


4

Ceria: The Misunderstood Abrasive


5

Ceria is not really a “hard” particle

Si

Si3N4

SiO2

Initial Wafer Surface

MohsHardness

6.5 – 7.0

9.0

ceria 6.0


6

Ceria Is A Much More Efficient AbrasiveSilica System Ceria System


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Ceria vs. Silica Polishing Mechanisms

• Conventional Dielectric Polishing Mechanism– Silica Based Slurry

– Ceria Based Slurry

• New Chemistry Mechanisms on Dielectric Polishing for iDiel™6600– Rate Acceleration Mechanism

– Morphology of Ceria on Defectivity


8

Dielectric CMP Mechanism of Silica Based Slurry

Mechanical Abrasion Oriented• Fumed/Colloidal Silica Based Slurry:

– High abrasive concentration– Limited chemical contribution from high pH (dissolution)

Silica Surface

Si

-O

Si

O

Si

O

Si

OSi

Si

O

Si

O

HO

Si Si

Si

O

Si

OSi

Si

O

Si

O

OSi

OSi

HHHO

Si

HOH-

O --

---

- --

--

- ---

-


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+ +

+ ++ Ceria

Silica Surface

Si

-O

Si

O

Si

O

Si

OSi

Si

O

Si

O

HO

Si Si

Si

O

Si

OSi

Si

O

Si

O

OSi

OSi

HHHO

Si

HOH-

O

oxoanion

Particle Has Strong Chemical Interaction with Surface

Ceria Polishing Mechanism


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High Efficiency Rate Acceleration ChemistryCeria Rate Control Chemistry

0

500

1000

1500

2000

2500

3000

3500

Ceria Particle Ceria Particle with Rate ControlChemistry

PETE

OS

Rem

oval

Rat

e (A

/min

)

Higher Oxide Removal Rate with a Host of Rate Acceleration Molecules in Ceria SlurryMost Consistent Removal Rate with Chemistry Oriented Slurry


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Impact of Abrasive Morphology on Defectivity

To Lower Defect CountRounded Edge and CornerNarrow Particle Size Distribution

Ceria A

Scale = 50 nmSmall, uniform particles

with rounded edges

Ceria B

Scale = 50 nmLarge, uncontrolled particles

with sharp edges

145

363

470

187

1

42

0

100

200

300

400

500

Ceria A Ceria B Ceria CD

efec

t Cou

nts,

patt

ern

waf

ers

0

40

80

120

160

200 Scratch Num

ber, pattern wafers

AIT Counts

Scratch Number


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Semi-Sperse® 25E iDiel™6600

Abrasive Type

Chemistry

Particle Concentration(POU)

Ceria

High Purity (no KOH)Rate Control Additives

< 0.50%

pH ~ 11KOH

12.5%

Fumed Silica

MechanismBalanced Chemical

& MechanicalPrimarily

mechanical

Method of UseSingle Component

2X Concentrate Single Component

6X Concentrate

iDiel™ 6600 Comparison to Fumed Silica


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iDiel™ 6600 Comparison to Fumed Silica


Downforce

TEOS pattern RR

3 psi

6000 Å/min4700 Å/min

4 psi

BPSG/PSG defects (norm.) 0.2X (80% reduction)1X

TEOS defects (norm.) 1X 0.6X (40% reduction)

TEOS: SiN Selectivity 5:1 >50:1


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iDiel™6600 Low Cost of Consumable


Dilution

Typical Flowrate

6X

125 mL/min150 mL/min

2X

Polish Time (8K step) <100 sec125 sec

$ for Transportation / Logistics + 33% Reduction inSlurry Usage per Wafer = CoC


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Flow RateTime to

Planarize Slurry Usage

1 11

85%78%

66%

0%10%

20%30%

40%

50%

60%

70%

80%

90%

100%

iDiel 6600 TM Slurry Usage EfficiencyReduction in Slurry Usage per Wafer Pass measured on SKW 7 Wafers

iDiel 6600Fumed Silica Product

Nor

mal

ized

to F

umed

Sili

ca

~33% Reductionin Slurry Usage

iDiel™6600 Low Cost of Consumable


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Defectivity Reduction with iDiel™6600

Ref ILD6X141

Defectivity Comparison (SP1 total counts)(PSG Blanket Wafers, Post HF)

01 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Wafer Number

Def

ect C

ount

per

waf

er

DCODCN

Fumed Silica Slurry iDiel™6600 (Ceria)


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Example of Defect Classification by SEMVisonClass#25 : general micro-scratch


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Customer Validation of Microscratch Reduction

~ 50%Reductionon TEOS~ 80%

Reductionon PSG

Microscratch Count Comparison

0

Silica Based iDiel™6600Slurry Type

Mic

rosc

ratc

h C

ount

Per

Waf

er

PSGTEOS


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Planarization Efficiency of iDiel™6600 vs. SS25E®

on MIT PatternOxide Thickness at 50% Pattern vs. 10% Field LossMirra, 2-platen process, IC1000/Suba-IV3/3/3.5/100/118

0

5000

10000

15000

20000

25000

0 1000 2000 3000 4000 5000 6000

10% Field Loss(Å)

Thic

knes

s at

50%

Site

(Å)

SS25EiDiel 6600

Equivalent Planarization Efficiency


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iDiel™6600 Removal Rate On MIT PatterniDielTM6600: Thickness of "UP AREA" vs Time

Mirra, 2-platen process, IC1000/Suba-IV3/3/3.5/100/118

0

5000

10000

15000

20000

25000

0 20 40 60 80 100 120 140 160

Time (sec)

Thic

knes

s (A

) at 5

0% S

ite

SS25EiDiel 6600

~ 25% Reduction in Polish Time


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Summary

• Innovation Can Drive CoC Reduction• Unique Ceria Abrasive Properties Key To Achieving

Metrics– High Efficiency Abrasive– Chemically Enhanced Mechanism– Low Defects– Low CoC

Documents

Innovation in ILD Polishing: Ultra-Low Defects and Reduced CoO · High Purity (no KOH) Rate Control Additives < 0.50% pH ~ 11 KOH 12.5% Fumed Silica Mechanism Balanced Chemical &