resist materials issues beyond 22 nm-hp patterning hp

February 26, 2009

Resist Materials Issues Resist Materials Issues beyond 22 nmbeyond 22 nm--hp Patterninghp Patterning

for EUV Lithographyfor EUV Lithography

February 26, 2009

Shinji Tarutani

FUJIFILM CorporationResearch & Development Management Headquarters

Electronic Materials Research Laboratories

February 26, 2009

OutlineOutline

Current status of CAR EUV resistsCurrent status of CAR EUV resists

Pattern Collapse Pattern Collapse

MicrobridgingMicrobridging

ConclusionsConclusions

AcknowledgementsAcknowledgements

February 26, 2009

Current CAR EUV ResistsCurrent CAR EUV ResistsData courtesy of SEMATECH

ResolutionResolution LWRLWR SensitivitySensitivity Collapse (AR)Collapse (AR)

ITRS HVM SpecsITRS HVM Specs 22 (22 (nm)nm) < 2.2 (< 2.2 (nm)nm) < 10 (< 10 (mJ/cmmJ/cm2 2 )) > 2.5> 2.5FEVSFEVS--P1201EP1201E 22 (22 (nm)nm) 5.6 (5.6 (nm)nm) 14.5 (14.5 (mJ/cmmJ/cm2 2 )) 2.32.3

FEVS-P1201ETr = 50 nm

February 26, 2009

Problems with CAR for ResolutionProblems with CAR for ResolutionData courtesy of SEMATECH

Target Resolution < 22 nm 1:1 LinesTarget Resolution < 22 nm 1:1 LinesProfileProfilePattern CollapsePattern CollapseMicrobridgingMicrobridgingProcess Margin (CD Uniformity)Process Margin (CD Uniformity)

22 nm hp

Large impact !Large impact !

FEVS-P1201ETr = 50 nm

February 26, 2009

Capillary force

CAR Resist CollapseCAR Resist Collapse

MechanicalStrength

Adhesion

①【”bend”】

②【”break”】

③【”peel”】

Collapse modein present CAR

Swelling

AR = 2.3AR = 2.3

February 26, 2009

Physics of Capillary ForcePhysics of Capillary Force

P: Capillary pressure gradientP: Capillary pressure gradient: Surface tension: Surface tensionR: Radius of curvatureR: Radius of curvatureS: SpacingS: Spacing: Contact angle of rinse liquid on resist surface: Contact angle of rinse liquid on resist surface

Balanced withBalanced with…….. YoungYoung’’s modulus s modulus (Mechanical strength)(Mechanical strength)

Adhesion strengthAdhesion strength

: : Rinse liquidRinse liquid: : Resist materialResist material

February 26, 2009

NeagtiveNeagtive Tone Resists with scCO2 Dry Tone Resists with scCO2 Dry for Collapse Issuefor Collapse Issue

TMAH Development, TMAH Development, XX--linking type negative tone EB resistlinking type negative tone EB resist

High mechanical strength / low capillary force are promising forHigh mechanical strength / low capillary force are promising for collapsecollapse

Tr = 250 nm

Tr = 250 nm

February 26, 2009

NeagtiveNeagtive Tone Resists Demonstrate Tone Resists Demonstrate 30 nm30 nm--hp Patterning on Ehp Patterning on E--beambeam

Similarities of EUV and EB promise the resolution below hp 30 nmSimilarities of EUV and EB promise the resolution below hp 30 nm on EUVon EUV

Negative tone Fujifilm EB resist

February 26, 2009

Comparison between EUV and Comparison between EUV and ArFiArFi resistsresists

Resist Half pitch

Critical A.R.

2cos

(rel.) Swelling Mechanical

strengthEUV resist FEVS-P1201E(Styrene resin) 22 nm 2.3 2 Not

enough ? ?

Optimal ArFi resist(Acrylic resin) 46 nm 3.0 1 Not

enough ? ?

Negative tone resist (X-linking type) x scCO2 dry 60 nm >> 4 ~ 0 Not

enough ? High ?

Further control should be required on Further control should be required on ““surface tension /contact anglesurface tension /contact angle”” and and ““swellingswelling””. .

R

O O

X

R

EUV resist ArFi resist

February 26, 2009

MicrobridgeMicrobridge Formation Formation Dominated by Swelling in DevelopmentDominated by Swelling in Development

DeveloperDeveloper

SwellingSwellingLayerLayer

MicrobridgingMicrobridging

Deformation of patternDeformation of patternmight be occur by might be occur by ““swellingswelling””

22 22 nm hp nm hp patternspatterns

Positive tone EUV resist

Data courtesy of SEMATECH

February 26, 2009

Design Principles for Low Swelling Resists Design Principles for Low Swelling Resists

((i) Penetration of developer into filmi) Penetration of developer into film⇒⇒Hydrophilic surface (polymer)Hydrophilic surface (polymer)

(ii) Acid(ii) Acid--base equilibriumbase equilibrium⇒⇒

High High pKapKa acidic group (acidic group (ionizaitonionizaiton degree)degree)

(iii) (iii) SolvationSolvation of polymerof polymer⇒⇒

Hydrophilic polymerHydrophilic polymerLow molecular weight polymerLow molecular weight polymerWeak intermolecular interaction polymerWeak intermolecular interaction polymer

(iv) Diffusion into solvent layer(iv) Diffusion into solvent layer

+ OH- + H2O

OH O-

Development stepsDevelopment stepsDesign PrinciplesDesign Principles

①① Increasing rate of (ii) + (iii)Increasing rate of (ii) + (iii)⇒⇒

((i) < (ii) + (iii)i) < (ii) + (iii)

②② Increasing uniformity Increasing uniformity in development in development

UniformUniform

NonNon--uniformuniform SwellingSwelling⇒⇒ BridgingBridging

AggregationAggregation

solublesolubleunun--solublesoluble

February 26, 2009

QCM (in 2.38% TMAH)

-100

-50

0

50

100

150

0 50 100 150 200 250

Time (sec)

Freq

uenc

y (H

z)

MicrobridgeMicrobridge Suppression using Suppression using a Polymer with Controlled a Polymer with Controlled HydrophilicityHydrophilicity

QCM AnalysisQCM Analysis

Weight of film

Increase

DecreaseDissolution

Swelling

Uncontrolled PHS polymerDissolution < Penetration

Controlled PHS polymerDissolution > Penetration

Positive tone EUV resistsPositive tone EUV resists

February 26, 2009

MicrobridgeMicrobridge Suppression using Suppression using a Polymer with Controlled a Polymer with Controlled HydrophilicityHydrophilicity

EE--beam exposure (50 beam exposure (50 keVkeV))TMAH Development, TMAH Development, Positive tone EUV resistsPositive tone EUV resists

TrenchTrench

100 nm100 nm

75 nm75 nm

62.5 nm62.5 nm

Controlled Uncontrolled

Line and spaceLine and space

125 nm125 nm

100 nm100 nm

75 nm75 nmMicrobridge

Controlled Uncontrolled

Residue(Microbridge)

Residue(Microbridge)

Tr = 150 nm

February 26, 2009

Design Principles for Low Swelling Resists Design Principles for Low Swelling Resists

((i) Penetration of developer into filmi) Penetration of developer into film⇒⇒Hydrophilic surface (polymer)Hydrophilic surface (polymer)

(ii) Acid(ii) Acid--base equilibriumbase equilibrium⇒⇒

High High pKapKa acidic group (acidic group (ionizaitonionizaiton degree)degree)

(iii) (iii) SolvationSolvation of polymerof polymer⇒⇒

Hydrophilic polymerHydrophilic polymerLow molecular weight polymerLow molecular weight polymerWeak intermolecular interaction polymerWeak intermolecular interaction polymer

(iv) Diffusion into solvent layer(iv) Diffusion into solvent layer

+ OH- + H2O

OH O-

Development stepsDevelopment stepsDesign PrinciplesDesign Principles

①① Increasing rate of (ii) + (iii)Increasing rate of (ii) + (iii)⇒⇒

((i) < (ii) + (iii)i) < (ii) + (iii)

②② Increasing uniformity Increasing uniformity in development in development

UniformUniform


AggregationAggregation

solublesolubleunun--solublesoluble

Organic Developer !

February 26, 2009

NTD is a Good Choice for Low Swelling NTD is a Good Choice for Low Swelling 45nm trench128nm pitch

NA1.2dipole illumination

NTDDeveloper: FN-DP001Dynamic dev.-1

W-1

PTDDeveloper: OPD5262Dynamic dev.-2

W-2

W-1

W-2

43.8 nm

3.3 nm

42.6 nm

4.0 nm

42.7 nm

4.2 nm

41.2 nm

5.1 nm

NTD PTD

Mean

3 x STD dev.

Mean

3 x STD dev.

Tarutani et al., SPIE 2009, 7273-11.

February 26, 2009

NTD is a Good Choice for Low Swelling NTD is a Good Choice for Low Swelling

01020304050

3 4 5 6 7LWR, nm

frequ

ency

01020304050

3 4 5 6 7LWR, nm

frequ

ency

0

30

60

90

120

150

41 43 45 47CD, nm

frequ

ency

390

30

60

90

120

150

41 43 45 47CD, nm

frequ

ency

39

43 nm trench90 nm pitch

NA1.35dipole illumination

NTDDeveloper: FN-DP001Dynamic dev-1.

PTDDeveloper: OPD262Static dev.

43.2 nm

1.6 nm

43.3 nm

1.4 nm

4.8 nm

1.1 nm

5.3 nm

1.2 nm

NTD PTD

Mean

3 x STD dev.

Mean

3 x STD dev.

0

30

60

90

120

150

41 43 45 47CD, nm

frequ

ency

390

30

60

90

120

150

41 43 45 47CD, nm

frequ

ency

39

01020304050

3 4 5 6 7LWR, nm

frequ

ency

01020304050

3 4 5 6 7LWR, nm

frequ

ency

Tarutani et al., SPIE 2009, 7273-11.

February 26, 2009

NonNon--uniform uniform DeprotectionDeprotection also Causes Swellingalso Causes Swelling

　

0

50000

100000

150000

200000

250000

300000

10 12 14 16 18 20保持時間/ min

ELSD

　強度

2 (8.5)5 (16.5)5.6 (16.6)6.6 (18.2)10 (18.7)

Dose

Retention Time (min)

Inte

nsity

(a.u

.)

HalfHalf--exposed area consists of mixture of polymersexposed area consists of mixture of polymers


⇒⇒

AcidityAcidity

HPLCHPLC

- 400

- 200

0

200

400

600

800

1000

0 100 200 300 400 500 600Time (sec)

ΔFr

eque

ncy

(Hz)

FF2202- 01_0mJ Δ Frequency FF2202- 01_5mJ Δ FrequencyFF2202- 01_5.5mJ Δ Frequency FF2202- 01_6mJ Δ FrequencyFF2202- 01 7mJ Δ Frequency

Half exposed film (5, 6mJ)Half exposed film (5, 6mJ)

Fully exposed film (10mJ)Fully exposed film (10mJ)

Un exposed filmUn exposed filmSwelling

QCMQCM

February 26, 2009

ConclusionsConclusionsCAR resists demonstrate 22 nmCAR resists demonstrate 22 nm--hp patterning, hp patterning,

but pattern collapse and but pattern collapse and microbridgingmicrobridging restrict their resolution.restrict their resolution.

Capillary force is a major factor to improve collapse. Capillary force is a major factor to improve collapse.

Negative tone resist with low surface tension rinse might beNegative tone resist with low surface tension rinse might be a a promising candidate for sub 20 nmpromising candidate for sub 20 nm--hp patterning.hp patterning.

MicrobridgingMicrobridging is dominated by swelling and limits resolution of is dominated by swelling and limits resolution of positive tone CAR resists.positive tone CAR resists.

Optimization of polymer solubility enhance resolution at least oOptimization of polymer solubility enhance resolution at least on n EE--beam exposure. Uniform beam exposure. Uniform deprotectiondeprotection, development and rinse , development and rinse should cause further enhancement on resolution. should cause further enhancement on resolution.

February 26, 2009

AcknowledgementsAcknowledgements

ChawonChawon KohKoh at SEMATECH at SEMATECH

Thank you for your kind attention !Thank you for your kind attention !

resist materials issues beyond 22 nm-hp patterning hp

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