30 June 1986 E-Beam Calibration Of The Hipparcos Grid Pattern
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The Hipparcos project of the European Space Agency (ESA) is dedicated to the astrometry of 100.000 pre-selected stars with an accuracy of 2 milliarc-seconds by satellite1,2. The refocussing mechanism of the Schmidt (F/4.8; F = 1400 mm) telescope is manufactured at the TN° Institute of Applied Physics (TPD). Part of this mechanism is the grid unit, an optical block with the Hipparcos grid pattern on its convex surface (R = 1400 mm), which is positioned in the telescope focal plane. The Hipparcos mission requirements of ESA/MATRA for the grid pattern are reflected in the nanometer range. The main grid covers an area of 22.1 mm x 22.1 mm with 2688 parallel slits. The slitperiod is 8.20 micrometer and the slitwidth is 3.20 micrometer. The grid patterns for a number of units are manufactured by e-beam lithography on a chrome mask at the Centre Suisse d'Electronique et the Microtechnique (CSFM) with the use of the Philips Beamwriter. The grid pattern calibration process involves optical and e-beam methods. The e-beam metrology in the nanometer range is made possible by a dedicated Hipparcos software package on the Philips Beamwriter of the Delft Center of Submicrontechnology (CST). The main features are: - the x, y stage laser interferometer system - the marker search accuracy of 10 nm RMS - the use of an almost undeflected e-beam operation to minimize the effect of main beam deflection errors. The magtape containing the e-beam measurement data is processed on the Harris H800 super minicomputer at TPD. The resulting calibration data are used: - as a feed back to the pattern manufacturing process at CSEM - for verification with the ESA/MATRA specifications - to select the engineering and flight models and to provide the associated calibration data to ESA/MATRA.
© (1986) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
L. A. Fontijn, H. J. van Agthoven, M. R. van der Kraan, "E-Beam Calibration Of The Hipparcos Grid Pattern", Proc. SPIE 0632, Electron-Beam, X-Ray, and Ion-Beam Technology for Submicrometer Lithographies V, (30 June 1986); doi: 10.1117/12.963687; https://doi.org/10.1117/12.963687

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