PTBPTBs's Synchrotron radiation based metrology

PTB's Synchrotron radiation based metrologyPTB s Synchrotron radiation based metrology

Christian Laubisworking group EUV radiometryworking group EUV radiometry

PTB ‐the National Metrology Institute

About PTB:

PTB the national metrology institutePTB – the national metrology institute providing scientific and technical services

What are PTB's capabilities?

PTB measures with the highest accuracyand reliability – metrology as the corecompetence

www ptb dewww.ptb.de

2

PTB @ BESSY I, II, MLS

1982 – 1999: BESSY I BESSY II:circumference 250 m

PTB:

circumference 250 m electron energy 1.7 GeV

since 1999: BESSY II 10 beamline branchesfrom 400 nm (3 eV)

to 0.02 nm (60 keV)

UV X‐ray

Metrology Light Source MLSi f 48

EUV

since 2008: MLS 

8 beamlines

circumference 48 m electron energy 100 ‐ 630 MeV

8 beamlinesfrom 8 mm

to  4 nm (300 eV)

UVUV

3

THz EUVUV

Methods

‐ Source calibrationSource calibration

‐ Detector calibration

‐ X‐ray fluorecence analysis

L thi k d t i ti‐ Layer thickness determination

‐ EUV Reflectometry

‐ EUV Scatterometry

‐ EUV Exposures

4

EUV ReflectometryEUV Reflectometry

EUV  Beamline

EUV – beamline: Spot size

wavelength range 5.5 nm to 48 nm

4‐blade aperture at intermediate focus imaged onto sample position

4 4 2 1 1 2 0 1 0 1 24 x 4 mm2

measured spot size at sample position

1 x 1 mm2 0.1 x 0.1 mm2

6

Optics for EUV Sources

5 sr collector, 670 mm outer diameterdesigndesign

coatingmounted for measurements at PTB

7

mounted for measurements at PTB

EUV ReflectometryEUV Reflectometry

Soft X‐ray  Beamline

Soft X‐ray radiometry beamline at BESSY II

wavelength range 1 nm to 25 nm

EUV ellipso‐scatterometer

9

EUV ellipso‐scatterometer

EUV‐Ellipso‐Scatterometer

linear polarization analyzer

10

Selectivity of Brewster‐analyser 

Polarisation effects at EUV reticles

“horizontal  lines“ “vertical lines“

11

V. Soltwisch, et al., Proc. SPIE 9422 9422‐38 (2015)

Reflectometry: optical constants

EUV photomask absorber stack

substrate Si, SiO2‐buffer, TaN absorber, ARCsubstrate Si, SiO2 buffer, TaN absorber, ARC

optical constants determined from subsequently deposited SiO2, TaN, and ARC layers

12

data of Henke shown for comparison

Irradiation and Exposure experimentsIrradiation and Exposure experiments

Irradiation beamline: Experimental chamber

Experimental chamberExperimental chamberwith gas supply systemand load lock

Gases available: H2 and others, 5 Pa total pressure5 Pa total pressurecan be handled bydifferential pumping

14

Irradiation beamline: Spectral distribution

blue dashes:  spectrum after mirrorred line:  with additional Si  filter

integral power :  0.9  W (no filter)        2.5 nJ / pulse0.15 W (Si‐Filter) 0.4 nJ / pulse

15

Power density and spatial distributionclose focus

20 W/cm2 on 0.1 mm x 0.3 mm hot spot

Power densityfor different distances from focus.

standard focusTwo scalings eachfor best depiction of'Hot spot' and 'Cold spot'.p p

21 W/cm2 on 2.5 mm x 1.5 mm cold spot

16

EUV ScatterometryEUV Scatterometry

EUV Scatterometry

Scheme of scatterometry measurements

geometrical properties:• structure width• structure height

measurements

test pattern: • structure height• edge angles • edge profiles 

p

semi‐dense bright linesCD 180 nm, duty cycle 1:3

18

• …..

Comparison: Scatterometry vs. AFM

CDblue: scatterometry,  red: AFMoffset scatterometry:  ‐2.7(18) nm

19

The Community

262nd PTB Seminar EUV metrology Oct. 2011

273rd PTB Seminar VUV and EUV metrology Oct. 2013

290st PTB Seminar VUV and EUV metrology Nov. 2015 www.euv2015.ptb.de

20

290 PTB Seminar VUV and EUV metrology Nov. 2015                www.euv2015.ptb.de

Thank you for your attention

www.euv2015.ptb.de

21