X-ray spectroscopy and metrology with high-harmonic sources
Peter M. Kraus Advanced Research Center for Nanolithography (ARCNL), Amsterdam, The Netherlands. EUV Lithography Source Workshop, 06.11.2018 – HiLASE, Prague, Czech Republic. EUV lithography requires new XUV sources
Resolve structures during lithography and Understand EUV (13.5 nm) interactions to after production with sub-nm precision improve masks, pellicles, mirrors, resists…
L. Li et al., Chem. Soc. Rev., 2017, 46, 4855
Y. Zhang et al., J. Micro Nanolith. MEMS MOEMS 16, 023510 (2017)
Broadband XUV and soft x-ray imaging Ulrafast XUV and soft x-ray spectroscopy
We need an ultrafast, coherent, table-top XUV/soft x-ray source Solution: High-harmonic generation (HHG) High-harmonic generation
argon atoms
1300 nm Space ~ 1 mJ ~1014 W/cm2 20 eV 50 eV 120 eV =^ 60 nm =^ 10 nm
High-harmonic generation (HHG): Converting many IR-photons into one 3 XUV-photon Three-step model of HHG Typical parameters: E - 3 - Recombination 800 nm 3.17 Up - 2 - ~ 1 mJ Propagation ~ 1014 - 1015 W/cm2
XUV emission 0 r
Active Figure from: electron P. M. Kraus, H. J. Woerner, Angew. Chem. 57, - IP 5228 (2018). - 1 - Three-step model of HHG: Core P. B. Corkum, PRL 71, 1994 (1993) Ionization J. L. Krause, K. J. Schafer, K. C. Kulander, PRL 68, 3535 (1992)
Quantum theory of HHG: Electron M. Lewenstein et al., PRA 49, 2117 (1994) mean field Imaging needs in nanolithpgraphy
Lensless imaging with x-rays from HHG
Compared to a conventional microscope, the lenses are replaced with a computer algorithm
Collaboration with Stefan Witte & Kjeld Eikema (ARCNL)
Needs in lithography: Short wavelength, high average power Demonstrated HHG sources
S. Haedrich et al., J. Phys. B 49, 172002 (2016). MIR driver for cutoff extension in HHG
800 nm H9, H11, …. …, H31, H33, ….
frequency
laser electric field electric laser 0 0.5 1 1.5 2 2.5 0.8 1.4 2.0
time / fs displacement electron e- transit time / fs
1300 nm H9, H11, …. …, H67, H69, ….
frequency
laser electric field electric laser 0 0.5 1 1.5 2 2.5 3 3.5 4 1.2 2.2 3.2 time / fs e- transit time / fs P. M. Kraus, H. J. Wörner, Angewandte Chemie (2018) Longer driving wavelengths in the mid-infrared (MIR) allow to generate higher x-ray energies with a lower average power through HHG Soft x-ray high-harmonic generation
T. Popmintchev, Science, 2012
HHG up to 1.6 keV has already been demonstrated High x-ray flux requires a high repetition rate, few-cycle MIR source Technical realization of new HHG source
Amphos pump laser: 1 kW, 20 mJ, 50 kHz, 1-2 ps, 1064 nm
MIR-OPCPA 100 W, 2 mJ, 50 kHz, 35 fs, 2000 nm, CEP stable
The OPCPA will drive a unique EUV/soft x-ray HHG source (<600 eV / 2 nm) which will serve many collaborations within and outside of ARCNL. Expectations for HHG-source at ARCNL
New HHG source at ARCNL
S. Haedrich et al., J. Phys. B 49, 172002 (2016). EUV lithography requires new XUV sources
Resolve structures during lithography and Understand EUV (13.5 nm) interactions to after production with sub-nm precision improve masks, pellicles, mirrors, resists…
L. Li et al., Chem. Soc. Rev., 2017, 46, 4855
Y. Zhang et al., J. Micro Nanolith. MEMS MOEMS 16, 023510 (2017)
Broadband XUV and soft x-ray imaging Ulrafast XUV and soft x-ray spectroscopy
We need an ultrafast, coherent, table-top XUV/soft x-ray source Solution: High-harmonic generation (HHG) What happens in lithography?
New photoresists: tin-oxo cage compounds High EUV sensitivity and finesse exposure
exposure mask
t = ? ?
photoresist Y. Zhang et al., J. Micro Nanolith. MEMS MOEMS 16, 023510 (2017) wafer What happens in the photoresists? Mechanisms in photoresists
W. D. Hinsberg and S. Meyers Proc. of SPIE Vol. 10146, 1014604-1 (2017)
Processes in photoresists after exposure: - Metal-carbon bond dissociation - Oxidation state change - Spin state change Principles of ultrafast EUV spectroscopy
EUV VIS/DUV attosecond femtosecond metal probe-pulse pump-pulse filter sample metal filter EUV grating XUV-sensitized CCD camera
HHG target energy LUMO
HOMO C. J. Kaplan, P. M. Kraus et al., PRB 97, 205202 (2018) Core-level reflectivity is element, oxidation-state, and spin-state specific. Ideally suited to unravel the complex atomic-like chemical dynamics of photoresists. core level Reflectivity measures density of states
L3 L D1 3 D1
L G X U,K G
3d5/2 (-29.3 eV) 3d3/2 (-29.9 eV)
The XUV reflectivity measures the joint density of states between the core level and CBs Femtosecond dynamics in germanium DR/R
C. J. Kaplan, P. M. Kraus et al., PRB 97, 205202 (2018)
2 휔푝푒 휀 = 휀푐 + 2 2 휔푒 − 휔 − 푖휔훾 Iterative fit Measuring the XUV dielectric function
real imag.
Carrier Positions Carrier Amplitudes
C. J. Kaplan, P. M. Kraus et al., PRB 97, 205202 (2018)
Real part of the dielectric Imaginary part of the dielectric function function tracks carrier position tracks carrier population in p-states Time scales of carrier relaxation Holes: Holes:
t1 = 0.6 ps: intravalley scattering t = 3.2 ps: Carrier diffusion t2 = 4.8 ps: optical phonon decay and Auger recombination
Electrons: Electrons:
t1 = 0.4 ps: G-X & L-X scattering t = 3.2 ps: Carrier diffusion t2 = 5.5 ps: optical phonon decay and Auger recombination
Carrier Positions Carrier Amplitudes
C. J. Kaplan, P. M. Kraus et al., PRB 97, 205202 (2018)
XUV transient reflectivity is a detailed and simultaneous probe of carrier dynamics. Status at ARCNL: Spectroscopy of resists
2-color HHG (driving with 800+400 nm)
Currently measuring first broadband EUV absorption spectra. Ongoing collaboration with Sonia Castellanos and Fred Brouwer. XUV absorption of Ti-based resists
Transmission spectrum through TiO2
M2,3 edge 3p -> LUMO
33 eV Transmission
23 eV 45 eV
Pixel
Observation of Ti M2,3-edge in photoresist product Thank You!
Ongoing collaborations at ARCNL: HHG and EUV science group at ARCNL: Stefan Witte Filippo Campi Reinout Jaarsma Kjeld Eikema Sylvianne Roscam Abbing Faegheh Sajjadian Sonia Castellanos Maarten van der Geest (not in picture) Fred Brouwer Najmeh Sadegh (not in picture)