Optical Radiation Measurements
Charles S. Tarrio
Thomas B. Lucatorto
Please contact the technical staff before shipping instruments or standards to the address listed below.
Fees are subject to change without noTesting the Contamination Potential of Extreme Ultraviolet (EUV) Photoresistsice.
Calibrated transfer standard detectors for the far ultraviolet are available from NIST to cover the spectral region 5 nm to 254 nm. Users are furnished with the quantum efficiency as a function of wavelength; quantum efficiency is defined as the average number of photoelectrons per incident photon. Three detector types are available to cover this range: (1) a windowless silicon semiconductor photodiode for the wavelength region 5 nm to 254 nm (available under Service ID No. 40599S); (2) a windowless photoemissive diode with an Al2O3 photocathode for the wavelength region 5 nm to 122 nm; and (3) a MgF2 -windowed photodiode with a semi-transparent CsTe photocathode for the wavelength region 116 nm to 254 nm. The detectors have been extensively studied regarding radiometrically important parameters such as photocathode spatial uniformity and temporal stability of conversion efficiency. It should be noted that the silicon photodiode is not solar blind, while the windowless photoemissive diode is. Stray light considerations should be evaluated before making a choice for the 5 nm to 122 nm region.
The relative expanded uncertainties in the measured quantum efficiencies are 7 % to 22 % in the 5 nm to
NIST working standard calibrations are based on the rare gas ionization chamber in the 5 nm to 92 nm region, and on the calculable synchrotron flux from the NIST electron storage ring, SURF II, at wavelengths longer than 110 nm. Two facilities at SURF II are used in these calibrations, one in the 5 nm to 50 nm region and a second in the 116 nm to 254 nm region. A separate laboratory facility is used for the 50 nm to 92 nm calibration of working standards.
Outgoing detectors are calibrated by direct intercomparison with precalibrated working standards that are periodically recalibrated. Windowless Al2O3 photodiodes are fabricated in-house; the windowless Si photodiodes and the windowed CsTe photodiodes are procured commercially and tested for stability and spatial homogeneity. Only those photodiodes meeting stringent NIST quality specifications are selected as transfer standards. The calibration costs include the cost of the detector and screening services unless a recalibration of previously used detectors is requested.Special detectors that do not lend themselves to convenient on-site cross-calibration may also be calibrated at NIST if the detectors merit radiometric application and if the NIST calibration facilities are suitable and available for the particular device.
Testing the Contamination Potential of Extreme Ultraviolet (EUV) Photoresists (40600C).
Measurements of submitted photoresists are performed to test their potential to contaminate optical components in an EUV microlithography scanner. An EUV photoresist is exposed to EUV radiation from the NIST Synchrotron Ultraviolet Radiation Facility (SURF III) in the presence of an EUV optic under controlled conditions that simulate the configuration in an EUV microlithography scanner. The photoresist outgasses organic material during the exposure. After this controlled exposure, the thickness of the carbon deposited (from the EUV-cracking of the adsorbed organic species) on a witness sample (a small section of an EUV optic) is measured with spectral ellipsometry, and the measured value is provided in the calibration report. The witness sample is then subjected to a specified cleaning cycle in which atomic hydrogen converts the deposited carbon to volatile hydrocarbons. The witness sample is then analyzed by XPS, and the amounts of residual, non-carbon, elemental contaminates are measured and provided in the calibration report.
Special Tests of Extreme Ultraviolet (EUV) Photoresists (406001S).
This service is provided for customers requesting photoresist testing that deviates from the standard protocol of 40600C, such as by eliminating the cleaning of the witness sample and its analysis by XPS or by submitting multiple samples where the cost per sample might be reduced, particularly if only one sample is subjected to the full set of tests. Customers should contact Charles Tarrio before submitting a formal request.
The technical staff members performing the calibrations will be Charles Tarrio, Steven Grantham, Robert Vest, and Thomas Lucatorto.
References-Detector Calibrations in the Ultraviolet
Stable Silicon Photodiodes for Absolute Intensity Measurements in the VUV and Soft X-Ray Regions, E. M. Gullikson, R. Korde, L. R. Canfield, and R. E. Vest, J. Electron Spectrosc. Relat. Phenon., 80, 313 (1996).
Far Ultraviolet Detector Standards, L. R. Canfield and N. Swanson, J. Res. Natl. Bur. Stand. (U.S.), 92 (2), 97-112 (1987).
NBS Measurement Services: Far Ultraviolet Detector Standards, L. R. Canfield and N. Swanson, Natl. Bur. Stand. (U.S.), Spec. Publ. 250-2 (June 1987).
Time response of NBS windowless XUV radiometric transfer detectors, E. B. Saloman, Appl. Opt. 14, 1764 (1975).References - Extreme Ultraviolet (EUV) Photoresists
Tarrio C.; Grantham S.; Hill S. B.; et al., "A synchrotron beamline for extreme-ultraviolet photoresist testing," REVIEW OF SCIENTIFIC INSTRUMENTS 82, 073102 (2011).
Faradzhev Nadir S.; Yakshinskiy Boris V.; Starodub Elena; et al., "Resonance effects in photoemission from TiO(2)-capped Mo/Si multilayer mirrors for extreme ultraviolet applications," JOURNAL OF APPLIED PHYSICS 109, 083112 (2011).
Grantham S.; Tarrio C.; Hill S. B.; et al., "The NIST EUV facility for advanced photoresist qualification using the witness-sample test," Proceedings of SPIE 7969, 79690K (2011).
Hill S. B.; Faradzhev N. S.; Richter L. J.; et al., "Optics contamination studies in support of high-throughput EUV lithography tools," Proceedings of SPIE 7969, 79690M (2011).
Fedynyshyn Theodore H.; Goodman Russell B.; Cabral Alberto; et al., "Polymer Photochemistry at the EUV Wavelength," Proceedings of SPIE 7639, 76390A (2010).
Garg Rashi; Faradzhev Nadir; Hill Shannon; et al., "A simple null-field ellipsometric imaging system (NEIS) for in situ monitoring of EUV-induced deposition on EUV optics," Proceedings of SPIE 7636, 76361Z (2010).
Hill S. B.; Faradzhev N. S.; Richter L. J.; et al., "Complex species and pressure dependence of intensity scaling laws for contamination rates of EUV optics determined by XPS and ellipsometry," Proceedings of SPIE 7636, 76360E (2010).
Faradzhev N.S.; Hill S.B.; Lucatorto T.B.; et al., "EUV Lithography Optics Contamination and Lifetime Studies," Bulletin of the Russian Academy of Sciences: Physics 74, 28-32 (2010).
Calibrations Phone: 301-975-2200, Fax: 301-975-2950 NIST, 100 Bureau Drive, Stop 8363, Gaithersburg, MD 20899-8363