1 preliminary results of contamination control development...

Mar. 3rd, 2005 T.Aoki SPIE Microlithography

1

EUVA Contamination

Preliminary Results of Preliminary Results of Contamination Control Contamination Control Development in EUVADevelopment in EUVA

March. 3March. 3rdrd, 2005, SPIE Microlithography at San Jose, 2005, SPIE Microlithography at San JoseExtreme Ultraviolet Lithography System DevelopmentAssociation (EUVA) Contamination Research Group

T. Aoki, H. Kondo, S. Matsunari,Y. Gomei, H. Takase and S. Terashima,


2

EUVA Contamination

EUVA Contamination Control Project: TasksEUVA Contamination Control Project: Tasks

1. Capping Layer Development• Estimation of oxidation speed and its dependency

to H2O partial pressure, light intensity, …• Optimization of Ru coating conditions• Listing up other candidates and

screening by EUV/E-beam irradiation

2. Carbonization Mitigation/Cleaning• UV (172nm Xe2 lamp)+O2 cleaning• EUV+O2 cleaning• Estimation of carbon film growth/removal speed

and its dependency to O2 partial pressure,light intensity, cleaning time, …


3

EUVA Contamination

EUVA Contamination Control Project: SitesEUVA Contamination Control Project: Sites

Research Sites1. Himeji (Univ. Hyogo)2. Sagamihara (Nikon)3. Utsunomiya (Canon)

Research Laboratories1. SR “Super-ALIS” in Atsugi (NTT)

• light intensity/dose dependency test• H2O/CxHy partial pressure dependency test• cleaning test

2. SR+Undulator “NewSUBARU” in Himeji (Univ. Hyogo)high power irradiation (Long Undulator)

• accelerated experiments• material screening See the poster by Kakutani et al.See the poster by Kakutani et al.


4

EUVA Contamination

Apparatus at NTT Atsugi LaboratoryApparatus at NTT Atsugi Laboratory

source

foldingmirror

samplemirror

LL

monochrom

atic light

Irradiationchamber

Zr filter

PD

Super-ALIS beam-line & Apparatus @Atsugi


5

EUVA Contamination

Apparatus: Irradiation Chamber Apparatus: Irradiation Chamber Direct EUV light and reflected can be also monitored with the identical photo-diode.Constructed with UHV components and has few plastic components to mitigate the H2O/CxHy outgassing.TMP, cryo-sorption pomp, load-lock chamber.

Degree of vacuum 5E-7 Pa (6E-9 Torr) is achieved after baking.Degree of vacuum 5E-7 Pa (6E-9 Torr) is achieved after baking.

Irradiation Chamber Test Piece


6

EUVA Contamination

Residual Gas Analyses of the ChamberResidual Gas Analyses of the ChamberIrradiation Chamber RGA Spectrum: '04/10/01 #01

1.E-14

1.E-13

1.E-12

1.E-11

1.E-10

1.E-09

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201Mass Number [amu]

Cur

rent

[A]

H2O

N2, CO

CO2

O2

RGA Spectrumirradiation chamber

2×10−6 Pa, 1,300V, 2mA

RGA Spectrumirradiation chamber

2×10−6 Pa, 1,300V, 2mA

No significant CxHy peak (>45amu)No significant CxHy peak (>45amu)

H2O and CxHy is less than those of ETS by about one and a half order.


7

EUVA Contamination

EUV Light Intensity & Beam ShapeEUV Light Intensity & Beam Shape

Estimation of EUV intensity on TP

• Light source: Φ1.6mm• Solid angle: H35mrad, V1mrad• SR Current: 350 mA max.• Electron energy: 0.6 GeV• Two grazing-incident mirrors• One multi-layered folding mirror• One Zr filters for band restriction

22 mW/mm2

Beam Size: 1.6mm×1.0mm

100 times greater than thoseon exposure tool mirror surface

Photoresist ImagePhotoresist Image

exposed area

0.5mm

SEM ImageSEM Image


8

EUVA Contamination

EE--Beam Irradiation for Accelerated/OffBeam Irradiation for Accelerated/Off--line Testline Test

Carbon mapping Oxygen mappingSEM image

EB Irradiation ResultsEB Irradiation Results

H2O: 1E-4Pa, Si-Cap, 6hrs exposureBeam Diameter (AES) about 400µm

EB gun

Faraday cup manipulator

TMP

• Oxidation speed by EB isfaster than that by EUV.

• No carbon deposition and oxidation 1.5mm away

200µm


9

EUVA Contamination

Test Piece & Analysis Test Piece & Analysis

Si/Mo 50 pairs on Si wafer.With/without Si, Ru & other capping layerAnti-diffusion layer

On-line (in-situ) analysisEUV reflectance measurementOff-line (ex-situ) analysisSurface analysis with XPS (AES), SIMS, AFM, TEM, …

Test PieceTest Piece

ExperimentExperiment

Atomic AbundanceAmount of OxygenAmount of Carbon

Chemical StateDegree of Oxidation

Depth Profilewith sputtering

Oxygen DistributionMixing Evaluation(Diffusion Layer)

Analysis (XPS)Analysis (XPS)

See the poster by Takase et al.See the poster by Takase et al.More sensitive than reflectanceMore sensitive than reflectance


10

EUVA Contamination

Capping Layer DevelopmentCapping Layer Development

Candidate MaterialsCandidate MaterialsRu

Optimization of coating conditionNoble Metals

Resistance properties against oxidationLower electron mobility

OxidesBarrier for oxygen transferCatalytic effect

Diffusion Barrier LayerMitigation of oxygen transfer


11

EUVA Contamination

Oxidation Resistance Test by EUV IrradiationOxidation Resistance Test by EUV IrradiationXPS Results: Ru-cap, 1E-6Pa, 6hours EUV IrradiationXPS Results: Ru-cap, 1E-6Pa, 6hours EUV Irradiation

Ru/CRu/C SiSi

MoMo OO


12

EUVA Contamination

30354045505560657075

1.E-06 1.E-05 1.E-04 1.E-03 1.E-02Pressure/Pa

RuO

/(Ru+

RuO

x)/%

EUVREF

3.4

3.9

4.4

4.9

5.4

5.9

6.4

6.9

0 3 6 9 12Time/hour

SiO

x/nm

EUVREF

20

30

40

50

60

70

0 3 6 9 12Time/hour

RuO

x/(R

u+R

uOx)

/%

EUVREF

3.4

3.9

4.4

4.9

5.4

5.9

6.4

6.9

0 2 4 6 8Time/hour

SiO

x/nm

EUV

REF

20

30

40

50

60

70

0 3 6 9 12Time/hour

RuO

x/(R

u+R

uOx)

/%

EUVREF

EUV Irradiation under H2O IntroductionEUV Irradiation under H2O Introduction

Oxidation at irradiated areaOxide thickness increase as irradiation time and H2O pressure increase

Si

Ru

H2O: 1E-6 Pa H2O: 9E-4 Pa Exposure: 3hours

3.4

3.9

4.4

4.9

5.4

5.9

6.4

6.9

1.E-06 1.E-05 1.E-04 1.E-03 1.E-02Pressure/Pa

SiO

x/nm

EUVREF(a) (b) (c)

(d) (e) (f)


13

EUVA Contamination

EUV Irradiation under H2O IntroductionEUV Irradiation under H2O Introduction

Greater Ru oxidation undergreater H2O pressure

Greater Ru oxidation undergreater H2O pressure

Oxidation of Ru-cap (4hr exposure)

XPSRu oxidation of Ru-cap

No Ru Oxidationunder H2O 1×10−6 Pa

No Ru Oxidationunder H2O 1×10−6 Pa

XPS: O1s H2O 1E-6 Pa

Ref. dataH2O 1E-3 Pa

Not exposedREF


14

EUVA Contamination

EUV Irradiation under H2O IntroductionEUV Irradiation under H2O IntroductionSi oxidation of Ru-capped

XPS

Si oxidation of Si- and Ru-capped

XPS

Greater oxidation of Si below Ru-capunder greater H2O increased

Greater oxidation of Si below Ru-capunder greater H2O increased

4 hr exposure 4 hr exposure

Oxidation of Si under Ru-cap is reduced than that under Si-cap

Oxidation of Si under Ru-cap is reduced than that under Si-cap

SiO

x/(S

i+Si

Ox)

Si: Partial oxidation, Ru: no oxidationSi: Partial oxidation, Ru: no oxidation Coverage ?Coverage ?


15

EUVA Contamination

UV+O2 Cleaning: ApparatusUV+O2 Cleaning: ApparatusRemoving carbon film with UV exposure under

O2 containing conditionEstimation of cleaning speed and surface damageDependency to O2 partial pressure, light intensity, dose, cap material (Ru/Si)

UV lamp

RGAmain chamber

load-lockmanupulator

O2 injection

GV

TMP

TPlight guide

UV

O2

UV lamp

RGAmain chamber

load-lockmanupulator

O2 injection

GV

TMP

TPlight guide

UV

O2

Xe2 excimer lamp (172nm)Intensity: 50 mW/cm2 (max)Residual gas pressure: 2E-6 PaO2 pressure:1E-1~1E3 Pa

PerformancePerformance


16

EUVA Contamination

UV Cleaning with O2: Experimental Conditions UV Cleaning with O2: Experimental Conditions Cleaned C film sputtered: 1nm

O2 pressure 100 PaUV intensity 3.9 mW/cm2

SiMo

Cno C C

～

C NoC

test piece

SputteredSputtered

Both are in amorphous states.Sputter C can be replaced.Both are in amorphous states.Sputter C can be replaced.

Raman SpectrumRaman Spectrum

amorphous

diamond

graphite

Test PieceTest Piece

As ContaminatedAs Contaminated

Meiling et al. (2000): 4nm/minHamamoto et al. (2004): 2nm/min

Published ResultsPublished Results


17

EUVA Contamination

UV Cleaning with O2: ResultsUV Cleaning with O2: Results

C not deposited (cleaning 100min)C not deposited (cleaning 100min)

C deposited (cleaning 100min)C deposited (cleaning 100min)C deposited (cleaning 1min)C deposited (cleaning 1min)

Significant peak on C deposited area with 1min cleaning

No significant peak on non- C and C deposited area with 100m cleaning

UV+O2 Cleaning Rate: Si ratio corrected

0

10

20

30

40

50

60

0 20 40 60 80 100Cleaning Time [min]

Res

idua

l Car

bon:

Ato

mic

Rat

io [%

]

0.030 [nm/min]

0.009 [nm/min]

no carbon

no cleaning effect

Thickness of initial carbon filmof 1nm is assumed.

Evident cleaning effectEvident cleaning effect Cleaning Rate: ~0.03 nm/minCleaning Rate: ~0.03 nm/min


18

EUVA Contamination

SummarySummaryApparatus was Installed onto Synchrotron Facility

Setting-up of the system had been completed.Sub-systems for EB irradiation, H2O introduction had been installed. CxHy gas introduction can be made near future.

Preliminary Experiments had been StartedHigh degree of vacuum (5E-7 Pa) in the chamber.RGA spectrum shows low contaminants partial pressure.Brighter EUV light irradiation is available than commercial exposure tool mirror surface.Oxidation acceleration with H2O introduction is confirmedexcept for H2O pressure of 1E-6 Pa. Possible criterion ?Si oxidation under non-oxidized Ru Coverage ? O transfer ?It is confirmed that EB irradiation is available for capping layer materials screening with our setup.Cleaning rate of UV+O2 is about 0.03 nm/min in 100 Pa O2.Discrepancy Carbon density ?


19

EUVA Contamination

AcknowledgmentsAcknowledgments

This work was performed under the management of

Extreme Ultraviolet Lithography System Development

Association ( ) in the Ministry of Economy

Trade and Industry (METI) program supported by New

Energy and Industrial Technology Development

Organization ( ).

1 preliminary results of contamination control development...

Documents