XUV and EUV Applications with EUV Sources for Metrology2012 International Workshop on EUV and Soft X-Ray Sources, Dublin, Ireland, October 8-11, 2012 EUV Discharge Lamp Operation Manual

XUV and EUV Applications with EUV

Sources for Metrology

Rainer Lebert, Thomas Mißalla,

Azadeh Farahzadi, Christoph Phiesel, Urs Wiesemann, Wolfgang Diete

Bruker Advanced Supercon GmbH, Waltherstrasse 49-51,

51069 Köln-Dellbrück, Germany

2012 International Workshop on EUV and Soft X-Ray Sources, Dublin, Ireland, October 8-11, 2012

History on EUV Sources: DPP & LPP !


Studies on EUV metrology source stability, cleanliness,

integration: Paths to increased brightness sources

LPP source gold emission spectrum as supplied

from our partner LzH for

spectrophotometer

EUV-Lamp Platform prototype for up to 40 W EUV inband source from FhG-ILT

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

9 10 11 12 13 14 15 16 17 18

Sig

na

l, a

rb.

Un

its

Wavelength, nm

Center

12 Uhr

3 Uhr

6 Uhr

9 Uhr

Isotropy of emission spectrum of Xenon

from EUV-Lamp under different angles

Targetchamber

Source Imaging Optics

Infinity Laser

CCD-Camera

Discharge Produced :

Laser Produced : EUV-Lamp < 1 W EUV ib EUV-Source > 10 W EUV ib

LPP < 10 mW EUV i.b. for spectr. PoC Set UP HB-LPP


DPP Source Systems


High Voltage

Power supply

Vacuum Chamber Beamline

Capacitor bank

Application

Hollow Cathode

EUV-Lamp Principle


EUV Discharge Lamp Operation Manual controlled cw 250 Hz Operation

0

5

10

15

20

0 5 10 15 20 25 30 35 40 45 50

Time, ms

Vo

lta

ge

, a

.u.

-20

-15

-10

-5

0

5

10

15

20

EU

V-I

nb

an

d S

ign

al,

a.u

.

Voltage at Source

EUV-Signal


Spatial distribution (spectral resolved)

1mm

13,5 nm 10 nm


EUV Lamps emit mainly EUV ! But little inband EUV

Quantified distribution of emission over spectral channels as measured at EUV-Lamp.


Pulse Statistics DPP

0

200

400

600

800

1000

1200

1400

0.035 0.04 0.045 0.05 0.055 0.06

Abu

ndan

ce N

-Tim

es p

er In

terv

al

Oscilloscope Signal, Volt

Seq. 1

Seq. 2

Seq. 3 @ 10 kV

FIT 3

FIT 2

FIT 1

Best-Fit : STDEV =4.3 %, 4.2% und 3.6 %


EUV-inband Open Frame Resist Exposer TEUVL

EUV-lamp inside


EUV, XUV & VUV Spectroscopy

EUV-

Spectro-

photometer

GI R&D EUV Reflectometer NI R&D EUV Reflectometer

EUV-

MBR


Polychromatic

EUV-Reflectometer

2000 channels of 1.6 pm

Spot size:

< 0.1*0.5 mm²

Spot Exposure

< 20 second

Throughput

> 90 spots / hour

Precise Multilayer Metrology:

EUV-Reflectometer Mask Blank Reflectometer : MBR

14

Spectral resolution 1.6 pm

WL calibration ± < 2 pm

WL reproducibility ± < 1 pm

Spot Size < 50 µm × 1mm

Spectral range 12 to 15 nm

Spectral channel width 1.6 pm

Exposure time per spot 20 s

Evaluation time per spot 10 s

Angle of incidence 6° (5°-

10°)

Angle of incidence precision < 100 µrad

Dynamics > 15 bit

Min. reflectance capability < 0.01 %

EUV-Lamp

Service Port

EUV-

Lamp

CCD

PSD

Laser

EUV-Lamp: e.g. > 300 Mpulses

> 100 k spots (> 30M 10 pm Channels)

> 10.000 blanks with 9 spots

Load-Port

EUV-MBR: in tool reference parallel to sample

Ref 1 Ref 2 blind Ref 1 Ref 2 sample

250 µm*100 µm²


0

20

40

60

80

100

120

140

0 50 100 150

Reflektometrie Stand:

Vergleich Maskenblank vor und nach Reinigung

Vergleich der

Mittelwerte über

alle Messpunkte.

Beobachtet wurde

eine leichte

Erhöhung der

Spitzenreflektivität

um ca. 2 %, eine

leichte

Verschiebung der

CWL_50 um 5 pm

zur kurzwelligen

Seite und eine

Erhöhung der

FWHM um 0.1 pm

im Mittel.

0%

10%

20%

30%

40%

50%

60%

12.5 12.7 12.9 13.1 13.3 13.5 13.7 13.9 14.1 14.3 14.5

10 10

15 15

20 20

25 25

30 30

35 35

40 40

45 45

50 50

55 55

60 60

65 65

70 70

73 73

74 74

75 75

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

77 77

77 77

78 78

79 79

80 80

85 85

90 90

95 95

100 100

105 105

0%

10%

20%

30%

40%

50%

60%

12.5 12.7 12.9 13.1 13.3 13.5 13.7 13.9 14.1 14.3 14.5

10 10

15 15

20 20

25 25

30 30

35 35

40 40

45 45

50 50

55 55

60 60

65 65

70 70

73 73

74 74

75 75

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

77 77

77 77

78 78

79 79

80 80

85 85

90 90

95 95

100 100

105 105-2.0%

-1.0%

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

12 12.5 13 13.5 14 14.5 15

I

II

Delta

0%

10%

20%

30%

40%

50%

60%

12.5 12.7 12.9 13.1 13.3 13.5 13.7 13.9 14.1 14.3 14.5

10 10

15 15

20 20

25 25

30 30

35 35

40 40

45 45

50 50

55 55

60 60

65 65

70 70

73 73

74 74

75 75

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

77 77

77 77

78 78

79 79

80 80

85 85

90 90

95 95

100 100

105 105

0%

10%

20%

30%

40%

50%

60%

12.5 12.7 12.9 13.1 13.3 13.5 13.7 13.9 14.1 14.3 14.5

10 10

15 15

20 20

25 25

30 30

35 35

40 40

45 45

50 50

55 55

60 60

65 65

70 70

73 73

74 74

75 75

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

76 76

77 77

77 77

78 78

79 79

80 80

85 85

90 90

95 95

100 100

105 105


13.500

13.505

13.510

13.515

13.520

13.525

13.530

13.535

0 20 40 60 80 100 120 140

x,y, mm

CW

L_

50

, n

m

0.503

0.504

0.505

0.506

0.507

0.508

0.509

0.510

0.511

0.512

0.513

0.514

FW

HM

, n

m

CWL_50

FWHM

32 pm10 pm

MBR Sensitivity: Diagonal Scan over Mask Blank

(0.01 nm !)


Stepping Measurement over Structured Mask Moving Measurement over structured mask

0%

10%

20%

30%

40%

50%

60%

12.5 12.7 12.9 13.1 13.3 13.5 13.7 13.9 14.1 14.3 14.5

Wavelength, nm

Re

fle

cta

nc

eX014_000Y006_000

X014_000Y007_000

X014_000Y008_000

X014_000Y009_000

X014_000Y009_500

X014_000Y010_000

X014_000Y010_500

X014_000Y011_000

X014_000Y012_000

X014_500Y007_500

X014_500Y008_500

X014_500Y009_500

X014_500Y010_500

X014_500Y011_500

X014_500Y012_500

X014_500Y013_500

X014_500Y014_000

X014_500Y014_500

X014_500Y015_500

X015_000Y006_000

X015_000Y007_000

X015_000Y008_000

X015_000Y009_000

X015_000Y010_000

X015_000Y011_000

X015_000Y012_000

X015_000Y013_000

X015_000Y014_000


Limit of Measurement: Reflection from Substrate

Dynamics of Measurement > 1 / 100,000 (> 16 bit)


Improvements and extensions on actinic spectral metrology :

Concept for flexible spectral characterization of samples

Detector Sample stage

Collector

Main in-vacuum optical units of CXUVS collector

module, sample stage unit and detector unit.

Can Measure:

•Window / Foil transmission,

•Grazing Incidence down to < 1°

•Normal Incidence up to 85°

•Gas transmission


Low Power Gold LPP Source (< 5 mW EUV inband) used

LPP < 5 mW EUV i.b. for spectr.

0

20

40

60

80

100

120

10 11 12 13 14 15 16 17 18 19 20

Inte

gral

ove

r C

CD

, ar

b.

Un

its

Wavelength, nm

58 Spectra within 21 minutes !TRANS_11_24_31

TRANS_11_24_43

TRANS_11_24_48

TRANS_11_25_02

TRANS_11_25_07

TRANS_11_25_25

TRANS_11_25_29

TRANS_11_25_34

TRANS_11_25_38

TRANS_11_25_43

TRANS_11_25_50

TRANS_11_25_55

TRANS_11_26_01

TRANS_11_26_06

TRANS_11_26_11

TRANS_11_26_16

TRANS_11_26_20

TRANS_11_26_36

TRANS_11_26_42

TRANS_11_27_04

TRANS_11_27_38

TRANS_11_27_57

TRANS_11_28_16

TRANS_11_28_21

TRANS_11_28_26

TRANS_11_28_31

TRANS_11_28_36

TRANS_11_28_40

TRANS_11_28_46

TRANS_11_28_50

TRANS_11_28_55

TRANS_11_29_01

TRANS_11_29_08

TRANS_11_29_13

TRANS_11_29_19

TRANS_11_29_43

TRANS_11_29_58

TRANS_11_30_09

TRANS_11_30_13

TRANS_11_30_18

TRANS_11_30_23

TRANS_11_30_27

TRANS_11_30_34

TRANS_11_30_52

after 7 minutes


GOLD LPP Spectral Fluctuations

0

20

40

60

80

100

120

10 11 12 13 14 15 16 17 18 19 20

Inte

gral

ove

r C

CD

, ar

b.

Un

its

Wavelength, nm

58 Spectra within 21 minutes !TRANS_11_24_31

TRANS_11_24_43

TRANS_11_24_48

TRANS_11_25_02

TRANS_11_25_07

TRANS_11_25_25

TRANS_11_25_29

TRANS_11_25_34

TRANS_11_25_38

TRANS_11_25_43

TRANS_11_25_50

TRANS_11_25_55

TRANS_11_26_01

TRANS_11_26_06

TRANS_11_26_11

TRANS_11_26_16

TRANS_11_26_20

TRANS_11_26_36

TRANS_11_26_42

TRANS_11_27_04

TRANS_11_27_38

TRANS_11_27_57

TRANS_11_28_16

TRANS_11_28_21

TRANS_11_28_26

TRANS_11_28_31

TRANS_11_28_36

TRANS_11_28_40

TRANS_11_28_46

TRANS_11_28_50

TRANS_11_28_55

TRANS_11_29_01

TRANS_11_29_08

TRANS_11_29_13

TRANS_11_29_19

TRANS_11_29_43

TRANS_11_29_58

TRANS_11_30_09

TRANS_11_30_13

TRANS_11_30_18

TRANS_11_30_23

TRANS_11_30_27

TRANS_11_30_34

TRANS_11_30_52

after 7 minutes


CEUVS example: 1 min exposed 50 µm diameter spot

Compared to PTB: MADT < 1 % absolute

ML Reflection and transmission of Si-nitride windows, compared with the measurement on

the same samples at PTB

The near normal reflection measurement for multilayer

samples, compared with the measurement on the same

sample at PTB


X-ray Microscopes

(“Water window” 2.4 < l < 4.4 nm)

• German Research Network (Coordinator: Bruker ASC)

• High brightness LPP and DPP sources

• Grazing incidence, multilayer, and diffractive (zone plate) optics

• Resolution ~30nm, ~20µm field

• Tomography, Cryo

Experience with the demands of Mask Metrology

(Source & Optics Integration and Alignment; Nanometer Sample Positioning,

UHV, Mechanical Stability; Vibration controlled architecture, Detectors etc.)


Results from X-Ray Microscopy

M. Benk, K. Bergmann, D. Schäfer (2008)

Rayleigh resolution <40nm

1000 x magnified diatoms and 80 nm latex spheres

1000 x magnified diatoms

40 nm Rayleigh Resolution

demonstrated

Single Line (< 0.5 % bandwidth)

brightness of

7 W/mm²/sr with DPP

and

> 60 W/mm²/sr with LPP

achieved


Imaging: EUV Transmission Microscopy Since 2005

CCD

Sample

Chamber

Beamline

EUV-Lamp

Collector

Objective

Designed for NA = 0,2 ;

i.e. < 100 nm resolution


Dark Field Transmission EUV-Microscopy since 2007

Small structures below 250 nm exhibit significantly higher contrast in EUV dark field images

compared to 1 mm and 500 nm structures

Bright field Dark field E-Mik

SimulationCCD-Image SimulationCCD-Image

0th order 1st order


Modification: Reflective Mode for Mask Blanks


First Results on “programmed” defects on ML

Structured pits on a multilayer mirror:

Stefan Herbert

26th European Mask and Lithography

Conference


Actinic Defect Inspection fundamentals:

Result PoP Experiment

Fig. 2 : Profile of a dark field EUV image of ML mirror sample

(left) and the corresponding AFM scan (right). The equivalent

sphere diameter is 45 nm, the height is 7 nm.


Actinic Defect Inspection fundamentals:

R&D Grade ABIT in Operation

Photo of the R&D ABIT as in operation

EUV source

Collector CCD camera

Schwarzschild

objective

Mask holder


Instrument for the Measuring of EUV

Reflectance and Scattering - MERLIN


Proof of concept for

Wide Angle XUV GI Scatterometry

Straight forward compact Proof of feasibility experiment set-up with available lab

components at BASC.

< 1mm² spot

>5° AOI

< 10 s per image

No beamstop

Wavelength and spectral

distribution flexibility of

EUV-Lamp with different

working gases

Achieved:

Accuracy of CD < ± 2 nm

Reproduc. < 0.06 nm rms

< 0.2 nm PV


CD-WA-XUV-Scatterometry: First results

Simulation of expected result is in agreement

Typical Result obtained with PoP set-up


PoC EUV Source with minimum pulse energy; flexible Laser

0.0E+00

2.0E+08

4.0E+08

6.0E+08

8.0E+08

1.0E+09

1.2E+09

1.4E+09

1.6E+09

1.8E+09

2.0E+09

7.0 9.0 11.0 13.0 15.0 17.0

Wavelength, nm

Yie

ld,

ph

oto

ns

/(p

uls

e*s

r)

150 ps 1.85%

900 ps 1.25%

2 ns 1.14%

Si-Edge

Liquid Tin Target (80:20 Sn:Pb)

+

R&D all solid state laser with

variable pulse length (25 W; 10 kHz; 2.5 mJ)


Outlook: HB source Investigation:

Potential for > 300 W/mm²/sterad

9 times magnified inband EUV-Image of source and horizontal profile on

CCD with 20 µm pixel. Schema of set-up and in RAC-Lab as insert.

Multilayer Mirror

Spherical Multilayer

Mirror

Plasma

Image of Plasma Source

Targetchamber

Source Imaging Optics

Infinity Laser

CCD-Camera

Discussion of configurations matched to customer’s demands for actinic mask metrology


Summary : EUV Solutions with lab sources

Mask Tools

0%

10%

20%

30%

40%

50%

60%

70%

12.5 12.7 12.9 13.1 13.3 13.5 13.7 13.9 14.1 14.3 14.5

Wavelength, nm

Refl

ecta

nce

1

2

3

4

5

6

7

8

9

10

Nano Tools Resist Tools

GIXUVR on 5 nm layers 5 deg

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

6 7 8 9 10 11 12 13 14

Wavelength, nm

Re

fle

cta

nce LaLu 5 deg

LaSc 5 deg

GdSc 5 deg

DySc 5 deg

Si L-edge

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

10 11 12 13 14 15 16 17 18

Wavelength [nm]

Refl

ecti

vit

y

( ) Filter

Xenon

TT

Tl

Si with SiO2-Layer, Reflection Angle 4,5°

Experiment Fit

EUV-Sources


www.bruker-asc.com

A Former ACCEL Instruments & AIXUV Business

ASCASC

Thank you for your attention

We gratefully acknowledge funding from the BMBF

In the framework of the Catrene (13N10572, CT301, EXEPT”)

Documents

XUV and EUV Applications with EUV Sources for Metrology2012 International Workshop on EUV and Soft X-Ray Sources, Dublin, Ireland, October 8-11, 2012 EUV Discharge Lamp Operation Manual