Development Status of Canon’s EUVL Exposure...

Slide 11 1February 26, 2009 7271-68 Slide 1International EUVL Symposium, October 19-21, Prague Slide 1

Development Status of Development Status of CanonCanon’’s EUVL Exposure Tools EUVL Exposure Tool

Akira Miyake, Takayuki Hasegawa,Hiroyuki Kubo, Shigeyuki Uzawa

Canon Inc.


Outline Outline

Development schedule- EUVL exposure tool roadmap

Mirror fabrication and evaluation- Surface figuring

- Multilayer evaluation

Optics lifetime- Atomic hydrogen cleaning

Optical design- 6-mirror high-NA PO

Summary


EUVL Tool RoadmapEUVL Tool RoadmapITRS2008 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

2 year cycle (nm) 45 32 22 16 11 8DRAM (hp)

Flash (hp)57 50 45 40 36 32 28 25 23 20 18 16

45 40 36 32 28 25 23 20 18 16 14 13

HVMPlatform

HVM tool (VS3)TP Enhancement

HVM tool (VS2)NA > 0.32

SFETInstalled at SELETE

Prototype

6-mirror (PO1) NA0.3In-house test

Specifications of VS2NA > 0.32

Aberration < 0.35 nm RMS

Flare 5 %

Dense Lines < 25nm

Isolated lines 17nm

Dense Contacts < 28nm

Overlay (SMO) < 3 nm

Throughput 100wph@200w IF10mJ/cm2


PO1 SystemPO1 System

PO1 is being fabricated to evaluate and improve our fabrication technology.

FeaturesLow-thermal expansion ceramic structure.Position of 5 mirrors are controlled in real time.

High stability of mirror position against vibration.Aberration can be compensated.

Mirrors

NA 0.3

Slit size 26 x 2 mm2

Aberration 0.55 nm RMS

Flare 7 %


0

0.5

1

1.5

2

2.5

0 0.25 0.5 0.75 1 1.25 1.5 1.75 2

IBF process capabilityIBF process capability

Effective spatial resolution range ; small beam IBF

Before IBF

After IBF

Figure correctionFigure correction

Effective range

F=0.88mm-1 (λ=1.2mm)

Spatial frequency(mm-1)

Pow

er

◆Small beam operation has 1.2mm wavelength resolution.

IBF tool

EUVA


1.0E-09

1.0E-08

1.0E-07

1.0E-06

1.0E-05

1.0E-04

1.0E-03

1.0E-02

1.0E-01

1.0E+00

0.01 0.1 1 10 100 1000 10000 100000 1000000

Spatial Frequency [1/mm]

Pow

er [

nm

2*

mm

]

MSFR: 53pmRMS

Figure: 38pmRMS

HSFR: 65pmRMS

Mirror Surface AccuracyMirror Surface Accuracy

Flare calculated from PSD curve is less than 5 %.(Range of spatial frequency that causes the flare is 4.5 decades.)

Figure accuracy also satisfies requirements for HVM tools.

2006

2008

2009


Wavefront Error of a Multilayer MirrorWavefront Error of a Multilayer Mirror

Wavefront of reflected light is determined by-shape of the mirror surface -phase shift on multilayer reflection.

Therefore, we have to measure and control them with high accuracy.

multilayer

wavefrontwavefront

Incident beam reflected beam


Reflection Phase MeasurementReflection Phase Measurement

Mo Si Mo SiSi Mo Si MoVacuum

Multilayer SurfaceIncident BeamReflected Beam

Standing wave is a superposition of the incident light and the reflected light.Electric field of the standing wave depends on phase shift and reflectivity.

Photoelectron intensity is proportional to electric field intensity on the multilayer surface approximately, because escape depth of low energy (<100eV) electron is small compared to thickness of each layer.

Photoelectrons


AtAt--wavelength Multilayer Evaluation Systemwavelength Multilayer Evaluation System

P-pol

S-pol

Sample

Rotation

M1 M3

M2

0th order

1st orderMonochromatic EUV light

Beam splitter (plane grating)

CCD 2Multilayer Sample

Electron Multiplier

CCD 1

Electron

beam intensity monitor

extinction factor : <1E-3Reflectivity Repeatability : 0.2%

Features- High accuracy of wavelength (Kr gas absorption spectrum, source emission spectrum) - Reflectivity and phase measurement at same time- Polarization control

Polarizer

EUV sourceLarge sample chamber MonochromatorSample chamber

Beam intensity monitor, electron detector

Slide 101010February 26, 2009 7271-68 Slide 10International EUVL Symposium, October 19-21, Prague Slide 10

Measured phase shift distributionMeasured phase shift distribution

Phase shift by multilayer reflection can be measured using standing wave method.Wavefront error caused by phase shift deviation was estimated to about 2mλ(σ).

Measured reflectivity and photoelectron intensity

-10

-5

0

5

10

0 50 100 150

-10

-5

0

5

10

30 60 90 120 150

radius (mm)

angle(deg)

wav

efro

nt e

rror

(m

λ)w

avef

ront

err

or

(mλ)

0

0.00000002

0.00000004

0.00000006

0.00000008

0.0000001

0.00000012

0.00000014

0.00000016

0.00000018

0

0

0

0

0

0

0

0

0

1

1

1

1

12.8 13.0 13.2 13.4 13.6 13.8

Reflectivity, photoelectron intensity

wavelength (nm)

1

radius

angle

Radial distribution

Directioanl distribution


Optics lifetime/Carbon depositionOptics lifetime/Carbon deposition

Carbon deposition rate was measured using SR beamlines.Repeated cleaning of deposited carbon on optical surface is needed.

Carbon deposition rate was estimatedusing experimental results under accelerated condition.-Decane gas introduced -SR beamline of Super-ALIS (NTT)

Assumption : - Decane pressure of 1E-7Pa- Linear extrapolation

Estimated carbon deposition rate of HVM exposure tool: 0.03 nm/hr (max)

Considering other factors:- EUV intensity distribution in PO- Source frequency- Residual gas species- Mitigation technologies

carbon deposition rate can be mitigated. EUVA


TMP

Valve 1

TMP

Contamination Cleaning Using Atomic HydrogenContamination Cleaning Using Atomic Hydrogen

Atomic hydrogen cleaning is a promising method forCleaning of deposited carbon on optical surface.

advantages : - High etching rate, - No oxidation effect concern : - Damage for resin materials

Damage test was performed for variety of materials.

Set up of irradiation tests

sample

Thermalshield

Tungsten filament

Hydrogen inlet

12Pa

1700-1800 deg


AFM (30µm range) SEM (10,000X)

Before After Before After

PTFE

THV

Epoxy

Surface Damage caused by Atomic Hydrogen IrradiationSurface Damage caused by Atomic Hydrogen Irradiation

EUVA Report2008

5 μm

2µm

Irradiation time : 180min (corresponds to the etching depth of 50nm)

Atomic hydrogen cleaning causes no significant damage to several kinds of resin material.


66--mirror highmirror high--NA Projection OpticsNA Projection Optics-- Target of Wavefront aberrationsTarget of Wavefront aberrations

Cross-pole illumination is chosen for HP16nm LSdue to large DOF with NILS >1.2 Target value of aberrations is <0.35nm RMSfor delta CD <1.12nm (7% of CD)

delta CD vs Aberrat ion Value

00.20.40.60.8

11.21.4

0.010 .040.070.090.120 .150.180.200.230 .260.280.310.340 .360.39

nm RMS

ΔC

D[n

m]

delta CD=1.12nm0.35nmRMS

- 1 - 0.5 0 0.5 1- 1

- 0.5

0

0.5

1

0

0.2

0.4

0.6

0.8

1

- 1 - 0.5 0 0.5 1- 1

- 0.5

0

0.5

1

0

0.2

0.4

0.6

0.8

1

SPIE2009


difficult to place

Large aberration

PerformanceNA : > 0.32Flare : ≦ 5％final aberration : ≦ 0.35 nmRMS

66--mirror highmirror high--NA Projection OpticsNA Projection Optics-- Optical designOptical design

difficult to place

difficult to place

All combination of 6Mirror(M5=convex, M6=concave. so, there are16 combination by M1,M2,M3 and M4 )

Best typeBest type

Negative power

Negative power

Negative power

Negative power

Difficult to image

Difficult to image

Difficult to image

Difficult to image

Difficult to place

■■Optical Design Result of Projection OpticsOptical Design Result of Projection Optics


SummarySummary

Fabrication technologies for projection opticsSurface figuring technologies satisfy requirements for HVM tool.At-wavelength multilayer evaluation system for thickness and phase measurements has been developed.

Optics lifetimeAtomic hydrogen cleaning method has advantage of low damage and reasonable etching rate.

Optics DesignOptical design of 6-mirror High-NA projection optics has been completed.


AcknowledgmentAcknowledgment

Part of this work was performed

under the management of Extreme Ultraviolet Lithography

System Development Association (EUVA)

in the Ministry of Economy Trade and Industry program

supported by

New Energy and Industrial Technology Development

Organization.

Development Status of Canon’s EUVL Exposure...

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