Existing Microbeam Facilities I.C. Noyan IBM Research Division, Yorktown Heights. Dept. of Appl. Phys. & Appl. Math. Columbia University

Microbeam facilities exist in all major synchrotrons. I will discuss the capabilities of: –Spring-8 –ESRF –APS –ALS –CHESS

Important Parameters Beam size on sample –Not necessarily equal – to the beam size at focus point. Divergence –These terms may differ in vertical and horizontal directions. # of photons in beam (intensity) –Divergence, beam intensity and the scattering process must be evaluated together. –Only the photons within the acceptance aperture of the process are relevant. ~ Normal x-section Oblique X-section

The data shown are either from the web pages or publications as of 1/2003. –The URL for each institution is referenced once at the beginning of each section. –Other data is referenced as required.

SPring-8 (Super Photon ring-8 GeV)

Industrial Consortium ID (13 companies) BL16 XU Undulator keV X-ray diffraction, X-ray fluorescence analysis and X-ray microbeam analysis for characterization of new industrial materials. Industrial Consortium BM (13 companies) BL16 B2 Bending Magnet keV XAFS and X-ray topography for characterization of new industrial materials. Hyogo (Hyogo Prefecture) BL24 XU Undulator keV Protein crystal structure analysis. Surface/interface analysis of inorganic materials. X-ray microbeam analysis. X-ray imaging.

BL24XU-Hyogo Beamline: Figure-8 undulator, vertically polarized X-ray beam. Vertical axis double crystal monochromator Beam size 100  m x 60  m at limiting slit (65 m from source) Horizontal/vertical divergence: 16/1  slit. Condensing optic: Asymmetric reflection ( ) from 100 surface crystals. Beam sample: 7.3  m x 6.4  m (horizontal/vertical), Beam sample: 7.7/5.3  rad

Kimura, et. al., APL Vol.77 #9, pp (2000)

ESRF - The European Synchrotron Radiation Facility Grenoble, France

Optics Flat Si mirror with 2 coatings Horizontal deflection: 0.15º (2.6 mrad) Cut-off energies: Si strip: 12 keV Pd strip: 24 keV Pt strip: 32 keV Vertical double flat crystal monochromator, fixed exit cam system (Kohzu) Angular range: 3-30 deg. Energy range: 4-37 keV for Si[111] crystals 7-72 keV for Si[311] crystals Micro-focusing elements: Bragg-Fresnel lenses (BFL) Fresnel zone plates (FZP) Compound refractive lenses (CRL) Size of beam at the sample location (V x H): 0.85  m x 1.5  40 m (EH1) and 1.2 x 60 m (EH2). 10 9, sample. µ-FID :Micro-Fluorescence, Imaging and Diffraction,

Detectors: Si(Li) detector Si drift diode detector PIN diodes, ionization chambers High resolution CCD cameras Medium resolution CCD camera gas filled (position sensitive) detector Beam: Monochromatic (4-35 keV), PINK beam mode: High energy bandwidth beams obtained directly from the undulator and mirror. These beams span several full undulator harmonics.

End Station Two large experimental hutches (~30m 2 each) accept differentset-ups: The microprobe facility: on a 2.5 x 1.2 m 2 granite optical table. focusing stage, pinhole stage, sample scanning stage with 2 sample holders (goniohead or slide holder) Video microscope, fluorescence, diffraction and normalization detectors as well as a high/medium resolution CCD camera stage. A 6 circle diffractometer, featuring a 3  m sphere of confusion is installed in the first experimental hutch and is operated jointly with the Univ. of Karlsruhe. The imaging and tomography set-up: second hutch, includes a high resolution rotation sample stage, a CCD X-ray camera standing on an optical bench and an optical microscope for alignment. Typical distance between the beam path and the surface of the tableis 38 cm. The experiment is currently operated in air but special sample chambers can be mounted for in vacuum measurements.

General Description of ID18F Schematic lay-out of the ID18 beam-line and the ID18F user end-station

The microprobe set-up is situated on a movable granite table in the 3 rd hutch of the ID18 beamline at about 59 m distance from the X-ray source. For the demagnification of the synchrotron source and for creating the micro-beam, parabolic compound refractive lens (CRL) is used. The CRL] is composed of different number of individual Al lenses depending on the energy of the focused beam. The typical focal distance is between m depending on the energy of the incoming beam leaving a relatively large place between the sample and focusing device for placing e.g. beam-shaping (pin-hole) or beam monitoring (photodiode, ionization chamber) elements in between.

The size of the focused beam is typically 1-2 micron vertically and micron horizontally

Imaging and tomography Phase-contrast imaging: Phase-contrast images of dry and wet samples can be taken on high-resolution film or by means of a high-resolution CCD camera. Typical exposure times are 10 ms to 5 s. Phase-contrast microtomography: Collecting a set of phase contrast images from different orientations of a sample in a parallel beam, it is already possible to perform 3D reconstruction (back-projection algorithm) by tomography at the micrometer scale. Micro-topography:, The high contrast and high resolution achievable is be used on the micro-FID beamline to observe details of the very fine topography of exotic or modified crystals used in microelectronics or laser technology Holography and interferometry: Gabor in-line holography (planar reference wave) or Fourrier holography (spherical reference wave) are feasible. The fine interference pattern obtained can be used for the high accuracy determination of optical density and refraction index.

Boron fiber reconstructed cross-section through a 100 micron boron fiber with a 15 micron tungsten-borite core, reconstructed from 700 phase-contrast images in 5 cm recording distance (E=20 keV) Three dimensional visualization of the broken tip of the fiber. A block has been cut out to show the inner structure of the fiber

Beamline ID13 The principal aim of the Microfocus Beamline is to provide small focal spots for diffraction and small- angle X-ray scattering (SAXS). Both single crystal and scanning diffraction (SXD) experiments are performed. Other applications, like scanning X-ray microfluorescence (SXRF), are feasible.

The main instrumental setups available for users are: The microgoniometer was developed for protein crystallography (PX) but can also be used for small- to medium cell crystallography. Typical beam sizes available are 5/10/30  m based on a condensing mirror and collimators. The scanning setup was developed for wide- and small-angle scattering. Typical beam sizes used are currently 2/5/10  m based on a condensing mirror in combination with tapered glass capillaries or collimators. The scanning setup can also be used for SAXS-experiments. For a beam size of about 10  m, the first order spacing of dry collagen can be resolved (65 nm). A 130 mm entrance window MAR CCD with 16 bit readout (~ 4 sec readout/frame) or a XIDIS detector with 12 bit readout (~ 0.1 sec readout/frame) are used for scanning.

X-rays are guided inside the capillaries by total external reflection. Critical angle depends on material and. ~ mrad. Capillaries tend to be very long (many cm) with a small slope. Usually 1 to 3 reflections. Non-imaging optic. Material: Pb-glass,  =5.3 g/cm3, Att. Length ~ 40  keV,  crit ~3 mrad.

Advanced Photon Source Argonne, IL

Sector 2: Micro-Techniques Group High-resolution imaging and diffraction experiments in the 1-4 keV and 5-35 keV energy regions. Develop new x-ray optics and techniques, with an emphasis on nanofocusing, coherence, 3D, and high-throughput methods.

Fresnel zone plate: A circularly symmetric array of annular zones which are alternately transparent and opaque. Provide diffraction limited x-ray imaging with a spatial resolution (in first order) approaching the dimension of the minimum, i.e., outermost, zone width. Provides many imaging orders. Different orders are focused at different points. Monochromatic and spatially coherent illumination of the zone plate is required in order to get a diffraction-limited focal spot size.

Energy Range Monochromaticity keV 10 4 E/dE Beam size4.2 x 1.6 mm 2 (hor x vert) FWHM Microprobe focus size 0.1 x 0.1 um 2 (hor x vert) Microprobe flux10 11 ph/um 2 /s/0.1% BW 2-ID-D - Sector 2, Insertion Device Branch Beamline High-resolution fluorescence and diffraction imaging,

Optical micrograph. Strain effects Small beams are needed.

Energy range keV Monochromaticity 10 4 E/  Beam size 2.0 x 1.0 mm 2 (hor x vert) FWHM Microprobe focus size 0.3 x 0.3 um 2 (hor x vert) Microprobe flux10 11 ph/um 2 /s/0.1% BW 2-ID-E - Sector 2, Insertion Side Device Branch Beamline Sub-micron x-ray fluorescence mapping: Detector: 3-element energy-dispersive, DE = 160 eV

2-ID-B - Sector 2, Insertion Device Branch Beamline High-resolution imaging, Coherent scattering Energy range keV Monochromaticity E/dE Beam size350 x 150 um 2 (hor x vert) FWHM Nanoprobe focus size50 x 50 nm 2 (hor x vert) Nanoprobe flux ph/s/0.1% BW Absolute-calibrated photodiodes Avalanche photodiodes Dispersive LEGe fluorescence detector LN2-cooled CCD cameras (direct, scintillator) Fast scan stage (0.8 nm resolution)

devices Tomographic (Figs. 1, 2, and 4) 3D and projection (Fig. 3) 2D images. Tomographic (Figs. 1, 2, and 4) 3D and projection (Fig. 3) 2D images. The last two years has seen an improvement in both spatial resolution an overall image quality in the tomography of integrated circuit components at beamline 2-ID-B. In collaboration primarily with a research group at the National Institute of Standards and Technology, we have been developing tomographic imaging techniques capable of resolving sub-micron sized structures, hence the name Z. H. Levine, A.R. Kalukin, M. Kuhn, S.P. Frigo, I. McNulty, C.C. Retsch, Y. Wang, U. Arp, T. Lucatorto, B. Ravel, C. Tarrio, J. Appl. Phys. 87, 4483 (2000). 1. A projective plot of the reconstruction of the integrated circuit. 2. Bayesian reconstruction of the integrated circuit interconnect using same data as in Normal incidence projection of an integrated circuit interconnect with an electromigration void. 4. Bayesian reconstruction of the ragged end of the aluminum interconnect shown in the right side in Fig. 3.

MHATT-CAT-Sector7 /UNICAT Beamline 34 White beam/monochromatic rad. K-B mirrors Spot size~1 micrometer diam. Divergence~2-4 mrad. Grain by grain strain/texture mapping. Depth resolved strain mapping.

Sample geometry G. Ice, B. Larson, Nature 415, (2002)

ALS-Berkeley Lab, Berkeley, CA

Beamline X-Ray Microdiffraction Source characteristics Bend magnet Energy range 6-12 keV Monochromator White light and monochromatic [two- and four-crystal Ge(111)] Calculated flux (1.9 GeV, 400 mA) At typically 8.5 keV: 1 x 10 9 photons/s/ µ m 2 /3x10 -4 BW (1 x 1 µ m spot), 1 x photons/s/3x10 -4 BW (100 x 300 µ m spot) Resolving power (E/E) depending on vertical convergence accepted Detectors X-ray CCD, image plate, fluorescence Si(Li) detector Spot size at sample 100 x 300 µ m down to 1 x 1 µ m Samples Format Typically less than 1 cm 2 x 1 mm thick Sample environment Typically air Special notes Microprobe, white-light, and monochromatic experiments Scientific applications Measurement of thin film strain, environmental science

Beamline High-Resolution Zone-Plate Microscopy Source characteristics Bend magnet Energy range eV Monochromator Zone-plate linear Calculated flux (1.9 GeV, 400 mA) Images with 1000 x 1000 pixels, 1000 photons/pixel recorded in 3 s at 517 eV, 0.2% BW Resolving power (E/E) Endstations X-ray microscope (XM-1) Characteristics Full-field soft x-ray microscope Spatial resolution 25 nm Detectors Back-thinned CCD camera Field of view 10 µ m single field; larger areas can be tiled together like a mosaic

Beamline X-Ray Fluorescence Microprobe Source characteristics Bend magnet Energy range 6-15 keV (with multilayer mirrors) 3-20 keV (without multilayer mirrors) Monochromator White light, multilayer mirrors in Kirkpatrick-Baez configuration Calculated flux (1.9 GeV, 400 mA) 3 x photons/s at 12.5 keV Resolving power (E/E) 25 at 12.5 keV Endstations Large hutch with optical table Characteristics X-ray fluorescence analysis of samples with high elemental sensitivity and high spatial resolution Spatial resolution 1.0 x 1.2 µ m Detectors Si(Li) Spot size at sample 1.0 x 1.2 µ m

CHESS, Ithaca, NY B2 bend magnet station, Tapered capillary optic, Smallest beam: 1000 A 6 keV photons/sec at the 12.3 keV (multilayer mono.) Microstructure evaluation (Laue photos).

Summary There are quite exciting machines that are doing microbeam x-ray analysis. This is a hot area: –ESRF now reports microbeam results as a separate category. All have advantages and limitations. –Ease of access, –Multiple techniques with minimal set-up. New rings are being designed with microspot beamlines.

Diamond will be built at the Rutherford Appleton Laboratory and is due to be available to users in September cells/ 3.0 GeV ring. Undulator beams up to 20keV High flux from multipole wigglers and wavelength shifters to energies greater than 100keV. Bending magnet sources from 40 keV to the IR. Microbeamline:. Source:undulator Optics:double crystal monochromator with micro-focussing giving: Wavelength range0.7Å – 1.3Å Bandpass10 -4 ConvergenceUp to 2mrad Energy stability0.25eV Beamsize at sample5 – 100  m Positional stability1% RMS on 5s timescale 3% RMS on 1hr timescale Flux10 12 ph/s in 30  m x 30  1Å

Goniostat:Single axis with 1  m sphere of confusion, Detectors: Area detector with no more than 1s readout time; Fluorescence detector Auto-loading and auto-changing of sample. Auto-alignment of sample both optically and with X-rays Sample cryogenic cooling to 4 – 100K The proposed machine at NSLS will provide ease-of-use and simultaneous analysis capabilities not available at other machines.