IMEC – ASML Process Technology Platform process technology platform Evolution of IMEC-ASML...

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IMEC – ASMLIMEC – ASMLProcess Technology PlatformProcess Technology Platform157nm Lithography Status Update157nm Lithography Status Update

Kurt RonseDirector Lithography Department

IMEC, Leuven (Belgium)

Veldhoven, 13 November 2003

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Outline

Introduction

157nm lithography status update

IMEC 157nm program

Summary and conclusions

Acknowledgements

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Outline

Introduction� IMEC-ASML process technology platform

157nm lithography status update

IMEC 157nm program


Acknowledgements

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IMEC

��Established by state government

(Flanders)Non-profit organization

Initial budget: 62MInitial Staff: ~70

��Largest independent R&D center in EuropeBudget: >145MStaff: >1270Collaboration with >450 partners

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Organization

Strategic partnershipsR. De Keersmaecker

Technical Support& Computer Logistics

W. Fluit

FinanceA. Vinck

Design Technology forIntegrated Information &Communication Systems

DESICSR. Lauwereins

Microsystems,Components &

Packaging

MCPR. Mertens

Silicon Process & DeviceTechnology

SPDTL. Van den hove

Industrialization &Training in

Microelectronics

INVOMECH. Maes

Scientific AdvisorH. De Man

President and CEOG. Declerck

Strategic Development UnitJ. Van helleputte

Business DevelopmentL. Deferm

Human ResourcesE. Daenen

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(Sub-)45nm Si Technology Research

��

to perform focused research on

�Advanced materials, process steps and modules�Novel device concepts (‘beyond classical CMOS’)

For technologies at least two generations ahead of manufacturing (> “N+2”)

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Si Technology Programs (IIAP)Concept

Advanced R&D on Si Technologyis carried out in

Industrial Affiliation Programs (IIAP)

��

Equipment supplier

Material supplier Key IC manufacturers

IMEC focus on process developmenton advanced equipmentwith advanced materials

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Today

IMEC-ASML process technology platform

Evolution of IMEC-ASML cooperation� 1990 : first ASML 248nm stepper installed at IMEC (PAS5000/70)

Industrial affiliation program on 28nm lithographyProcess training center for ASML application engineers

� 1999 : first ASML 193nm scanner installed at IMEC (PAS5500/900)Industrial affiliation program on 193nm lithography

� 2001 : ASML imaging team @ IMEC established (8 FTE)Joint projects on

� Optical extension and imaging development(e.g. double dipole, chromeless phase shift)

� (off-line and integrated) metrology development (e.g. electrical CD,…)� Long term exposure tool monitoring� …

� 2003 : first ASML 157nm scanner installed at IMEC (Micrascan VII)Industrial affiliation program on 157nm lithography

� 2004-2007 : plans under discussion…

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157nm critical challenges :ISMT stop light chart

��

Jan

-99

Mar

-99

Jun

-99

No

v-00

Dec

-00

Feb

-01

Jun

-01

Dec

-01

Jun

-02

Sep

-02

Au

g-0

3

Issues/Comments

Mask - Reticle blanks More work on lifetime of attenuators PSM absorbers - Pellicle Workable Hard Pellicle Solution is feasible. Soft Pellicle

lifetime is a major concern. Good progress on hard pellicles

Exposure Tools - Materials CaF2 Yield/quality enhancements continue to show

improvement. Both <111> & <100> crystals are needed. Champion <111> in spec and <100> close to spec. Add 45nm focus and reason for yellow.

Coatings Lifetime concerns versus environmental issues. - Lasers COO a concern due to material damage; linewidth

narrowing needed for 45nm. - Purging/Ctmn Substantial progress to dateResist - Chemistry Asahi resist achieved ~ 1 / � m transparency - Performance Timing is an issue. Concern over PEB Sensitivity,

Poisoning, and Transparancy. LER for 45nm node.Metrology/Inspection - Reticle Inspection through Hard Pellicle

Hard Pellicle provides significant inspection challenge & availability of tool still an issue; not field changeable.

Timing - 65nm half pitch - 2007 Mfg. Start

Legend Requires Invention/Potential Showstopper

Critical Issue/Development Requiredin 2003, node changed to 45nm Solution Known

SubstratePellicle

CaF2 (quality and quantity)Optical material contamination and lifetimeLight source (F2 laser)N2 Purging

Resist transparency and profilesProcess integration aspects

Masks

ExposureTool

Resist

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Outline

Introduction

Status of 157nm critical issues� 157nm resist status� 157nm exposure tool status� 157nm pellicle status� 157nm mask substrate status

IMEC 157nm program


Acknowledgements

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157nm resists2000-2001 : Absorbance challenge

Development of new chemistries� Siloxane, silsesquioxanes� Fluoropolymers

W. Conley et al, 3th International Symposium on 157nm lithography

Polymer absorbance : from 6 to below 1/µm

Abs

orba

nce

µm-1

Time

4

6

3

5

2

1

0.7 perfluorocarbon*

UV6

I

C

O

O

C(CH3)3F3CCF3

OH

n m

I

C

O

O

C(CH3)3F3CCF3

OH

n m

II

CF3

F3CO CH2 O CH2 CH3

F3CCF3

OH

n m

II

CF3

F3CO CH2 O CH2 CH3

F3CCF3

OH

n m

III

YX

CF3

F3C OHF3CCF3

O

O

III

YX

CF3

F3C OHF3CCF3

O

O

YX

CF3

F3C OHF3CCF3

O

O

n CF2

COO

n CF2 n

CF3

CF2CF2

CF3CF3

OH

nn CF2

COO

n CF2 n

CF3

CF2CF2

CF3CF3

OH

nn CF2

COO

n CF2 n

CF3

CF2CF2

CF3CF3

OH

n

CF2 CF2 n

CF3CF3

OH

nCF2 CF2 n

CF3CF3

OH

nCF2 CF2 n

CF3CF3

OH

n

RS-001

CH2CF2

F

FOH

CF3

HH

F

n

RS-001

CH2CF2

F

FOH

CF3

HH

F

n

OH

( )

OH

( )

OH

( )

OH

CF3F3C

( )

IBM/MITOH

CF3F3C

( )

OH

CF3F3C

( )

OH

CF3F3C

( )

IBM/MIT

248nm chemistry : UTR

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157nm resists2001-2002: resist transparancy allows thickness increase

Absorbance

012345678

Jan-01

Apr-01

Jul-01

Nov-01

Feb-02

May-02

Sep-02

Dec-02

Mar-03

Jun-03

Date

Ab

sorb

ance

[1/

um

]

110nm thick

barc

67 nm thick

silicon

110nm thick

silicon

200nm thick

barc

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157nm resistsStatus today

State of the art resist Absorbance < 1.0 /µm

< 60 nm resolution in 150nm thickness (NA=0.85, PSM)

F. Houlihan et al, 4th International Symposium on 157nm lithographyExposure : Exitech NA=0.85, Selete

100nm 90nm 80nm

70nm 65nm 60nm

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157nm resistsStatus today

Courtesy of Selete and Nissan Chemicals, 4th International Symposium on 157nm lithographyExposure : Exitech NA=0.85, Selete

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157nm resistsSummary

Significant resist progress� Absorbance of resist has decreased to below 1/um, allowing

imaging in resist thicknesses > 150nm

� Today’s best resists are capable of 60nm1:1 resolution(at 0.85NA, PSM) in 150nm thick resist

Further improvements needed� Line edge roughness is a challenge

� Etch resistance should be further improved

� Post-exposure delay sensitivity (amine contamination)

� Resist sensitivity

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157nm exposure toolCaF2 improvements

0

0,5

1

1,5

2

SD

B r

ms

[nm

/cm

]

157 nm193 nm (111)

materialfor /900

materialfor /1100

status 2001

material 1600

(100)(100)(111)

(111)

1998 2000 2001 2002 2003

system 4system 1-3

S CHOT Tlithotech

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157nm exposure toolFirst full field scanner successfully installed at IMEC

ASML MicraScanVII step&scanPlatform specs:Lens reduction ratio: 4XLens NA: variable 0.4 to 0.75Field size: 34 mm x 20 mmWafer size: 200 mmReticle size: 6” x 6” x 0.25”Partial coherence range: 0.3 to 0.85Reticle cleaning unit off-line

Interfaced to TEL Clean Track ACT8

ESI TMB-150 Total Amine Monitor

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130nm

100nm 90nm

80nm

S. Dana et al, 4th International Symposium on 157nm lithographyExposure : ASML MSVII NA=0.75, BIM


Binary mask, 0.75 NAConventional illumination

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70nm 1:1 L/S

F= + 0.1 µm

F= - 0.1 µm

Best focus

150 nm resist thickness

60nm 1:1.25 L/S

Binary mask, 0.75 NA

Dipole illumination

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157nm exposure toolSummary

Significant progress� First full field exposure tool installed in the field and

showing acceptable performance

� Intrinsic birefringence compensation successful(CaF2 <M111> and <100> crystal orientations)

Further learning needed� Long term optical path stability

(hydrocarbon and inorganic contamination risks mitigated ?)

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157nm pelliclethe issue

First option : Soft pellicle : 1 µm thick polymer :� Transparency� Radiation hardness

Pellicle: to protect pattern from defects

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157nm pellicleSoft pellicle

Soft pellicle lifetime (initial target : 200J/cm2 at 70% T)� No more progress since mid 2002, focus more on understanding

Transmission ratio from Initial

0

0.2

0.4

0.6

0.8

1

1.2

0 5 10 15 20

Dose E (J/cm2)

Tra

nsm

itta

nce

(A

.U)

Data presented at157nm Symposium,Antwerp Belgium, Sept., 2002

Data presented at157 nm SymposiumDana Point CA, May, 2001

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157nm pelliclesoft pellicle



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Alternative : Hard or ‘thick’ pellicle : 800µm thick quartz� Expensive� Optical element (aberrations, distortions)

157nm pelliclehard pellicle



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157nm pellicleSummary

Significant hard pellicle progress

� All hard pellicle imaging effects are understood andcan be compensated using lens manipulators

Further improvements needed

� Hard pellicle mounting needs to reduce local tilt

� Soft pellicle polymer development will improve CoO

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157nm mask substrateVUV cleaning can restore transmission

Principle VUV cleaning� Expectation that the transmission loss of F-doped quartz by CR-

airborne contamination is 1-2%(ref. T. Bloomstein et al., ISMT 157nm reticle handling meeting,San Diego, 2000)

� 172nm light in presence of oxygen generates dissociated oxygenradicals that break atomic bonds

ASML off-line UVO cleaner

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157nm mask substrateVUV cleaning can restore transmission

75

77

79

81

8385

87

89

91

93

150 155 160 165 170

Wavelength (nm)

Tra

nsm

issi

on

2% to 3% transmission recovery

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157nm mask substrateSummary

Significant progress

� VUV cleaning has been proven to restore mask substratetransmission

Further improvements needed

� Handling of reticles in fab, in mask shop, and in transportneeds to be checked for irreversible transmissiondegradation on the longer term

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Outline

Introduction

Status of 157nm critical issues

IMEC 157nm program� Objectives� Partners� Projects


Acknowledgements

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IMEC 157nm Lithography ProgramProgram objectives

IMEC157nm

ProcessProgram

Resist

benchmarkingO

ptical pathm

onitoring

Hard pellicle

printing157n

m r

etic

le

hand

ling

Resist

integration on

critical layers

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Int’l Sematech

AMDHPIBM

InfineonIntel

MotorolaPhilips

TITSMC

IMEC 157nm Lithography ProgramProgram partners

Non-Sematech membersMicron

SamsungST Microelectronics

IMEC157nm

ProcessProgram

Merch. mask shopsPhotronics

Dai Nippon Printing(Toppan Printing)

(DuPont)

Equipment suppliersASMLTELKLA-TencorLam Research

Resist suppliers

Arch/FujiFilmClariant

JSRTOK

BrewerNissan Chemical

Shin Etsu

SoftwareSynopsys

Mentor GraphicsASML Masktools

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157nm critical challenges update� 157nm resists

Steady progress (transmittance and lithographic performance)Significant further progress needed for 45nm node (LER, integration)

� Exposure tool (Micrascan VII)The world’s first 157nm full field scanner operational at IMECLong term optical path stability (contamination) to be investigated

� Hard pellicle printingHard pellicle imaging contributions understood and compensatedPellicle-flatness specs for mounting needs to be proven

� 157nm VUV reticle cleaningOrganic contamination effect limited (2-3%) and reversibleReticle handling procedures in wafer fab and mask shop to beinvestigated (long term reticle usage)

Summary� A lot of technical progress� Still a lot of challenges since target has moved to 45nm node

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Acknowledgements

Thanks for contributions from� IMEC SPDT/LITHO� ASML 157 nm development teams (Wilton, Veldhoven)� Infineon Technologies (providing the alternating PSM)� Resist vendors (Clariant, TOK, …)� ISMT (K. Turnquest, G. Feit, K. Dean)� Selete (T. Itani)

Thanks for funding :� Part of this work is sponsored through International Sematech� European Commision : IST–2000-30175 UV2Litho� Medea+ : T401 FLUOR

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