Imaging in the EUV region. Eberhard Spiller

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1 Imaging in the EUV region Eberhard Spiller

2 Introduction to Imaging Applications Astronomy Microscopy EUV Lithography Direct Reconstruction E. Spiller, June 11,

3 Imaging with light Waves move by λ in to sec Wave trains are to sec long Each wavelet contains less than 1 photon Eye responds in about 0.1 sec Everything is washed out! How can we see? E. Spiller, June 11,

4 Solutions 1) Use short observation time <10-15 sec need intensity, computer power, sample is destroyed 2) Generate standing waves that last need mirrors, lenses, coherence 3) Use simple objects (crystals): enhanced diffraction peaks low information content simple reconstruction, resolve atoms E. Spiller, June 11,

$object Optic Standing waves Image Moving Diffraction$

5 object Optic Standing waves Image Moving Diffraction pattern Fast detector Computer Image E. Spiller, June 11,

6 Material properties in the EUV All materials absorb for λ<110 nm n = 1 - δ, no lenses No single surface mirrors, R max < 1% Multilayer designs that minimize absorption can enhance normal incidence reflectance to 70% in the 11 to 14 nm wavelength range E. Spiller, June 11,

7 History of X-Ray Optics bias: high resolution images Röntgen, 1895 Shadow graphs, No lenses or mirrors Laue, 1912 X-ray-diffraction Bragg, 1914 Atomic resolution for crystals Ewald, 1916 Dynamical Theory Compton, 1923 Grazing incidence mirror, capillaries (1931) Kiessig, 1931 Thin film interference with x-rays DuMond&Youtz, 1935 X-ray peaks from multilayers, diffusion const. Bormann, 1941 Standing wave in crystal reduces absorption Kirkpatrik-Baez, 1948 Imaging with 2 cylinder-mirrors, zone plates Wolter, 1952 Imaging with 2 conic sections E. Spiller, June 11,

8 Recent History Möllenstedt,1966 Zoneplates by electron-beam Schmahl, 1969 Zoneplates by holography Spiller, 1972 Multilayers for XUV near normal incidence telescopes, microscopes, cameras, polarizers Spears, 1972 X-ray lithography (shadowgraphs) Walker, Golub, 1988 XUV telescopes for sun's corona SOHO, TRACE Hawryluk, Kinoshita 1988 EUV projection lithography Snigirev 1996 Multi-lenses Tinsley, 1998 Figure, finish of mirrors in 1 Å range EUVL LLC, 2001 EUVL cameras within diffraction limit FEL for x rays, 2009 Reconstruction in 3-D from diffraction patterns Future Challenge: Phase contrast for medical x-rays E. Spiller, June 11,

9 Multilayer Mirror Design 1971: Absorber in Node does not absorb 100% mirror is possible despite absorption E. Spiller, June 11,

10 Euv/X-ray Imaging Systems a b c e O pti c d f source detector g E. Spiller, June 11,

11 Normal Incidence Telescopes 1980: Contact Harvard Observatory (L. Golub) 1981: Arcsec resolution with 3 mirror at 67Å 1986: First launch of Sounding Rockets 1991: Launch of YOHKOH observatory 1995: Launch of SOHO observatory 1998: Launch of TRACE E. Spiller, June 11,

12 Multilayer telescope at IBM E. Spiller, June 11,

13 Properties of IBM system E-beam evaporation low energy minimizes diffusion Ion polishing after deposition smoothes boundaries In situ x-ray reflectivity for immediate quality control E. Spiller, June 11,

14 White Sands Missile Range E. Spiller, June 11,

15 White Sands Recovery E. Spiller, June 11,

16 First good photo, 1989 Trace, 10/10/98, λ=17.1nm Eclipse on July 11, 1991 gave estimate of scattering from multilayer mirror. E. Spiller, June 11,

17 TRACE, 10/10/98, λ=17.1nm E. Spiller, June 11,

18 Two mirror Schwarzschild for Microscopy and Lithography E. Spiller, June 11,

19 (R. Hudyma) E. Spiller, June 11,

20 Direct Reconstruction Simple? Needed: Coherent source (FEL) Many patterns for 3-D Object is destroyed at each exposure Inject identical particles, different orientation Computer power and algorithms E. Spiller, June 11,

$Diffraction patterns of exploding specimen are obtained and simple specimen are$

21 First Experiments Graded Multilayer separates direct and scattered beam Light from exploding specimen does not reflect. Diffraction patterns of exploding specimen are obtained and simple specimen are reconstructed Diffraction Patterns of Nano Particles injected into the beam have been recorded and reconstructed E. Spiller, June 11,

22 Challenge: Use phase contrast in medical x-rays Promise: δ is 10 4 times bigger than β Enhanced contrast, less radiation damage Problem: Small deflection angle, except for very small features Experiments with synchrotron radiation and microscopic objects. Interferometry or large distance to detector Multiple gratings suppress absorption contrast (Pfeiffer 2008) Probable path: Absorption contrast for large features, phase contrast for small features? E. Spiller, June 11,

23 Figure 1. A portion of the solar corona seen in the Fe IX/X lines at λ=173å on 7/29/98 from the TRACE spacecraft. Courtesy NASA/TRACE. E. Spiller, June 11,

EUV and Soft X-Ray Optics

EUV and Soft X-Ray Optics David Attwood University of California, Berkeley Cheiron School September 2012 SPring-8 1 The short wavelength region of the electromagnetic spectrum n = 1 + i,