Binary pseudo-random gratings and arrays for calibration of the modulation transfer function of surface profilometers: recent developments
The major problem of measurement of a power spectral density (PSD) distribution of the surface heights with surface profilometers arises due to the unknown Modulation Transfer Function (MTF) of the instruments. The MTF tends to distort the PSD at higher spatial frequencies. It has been suggested [Proc. SPIE 7077-7, (2007), Opt. Eng. 47 (7), 073602-1-5 (2008)] that the instrumental MTF of a surface profiler can be precisely measured using standard test surfaces based on binary pseudo-random (BPR) patterns. In the cited work, a one dimensional (1D) realization of the suggested method based on use of BPR gratings has been demonstrated. Here, we present recent achievements made in fabricating and using two-dimensional (2D) BPR arrays that allow for a direct 2D calibration of the instrumental MTF. The 2D BPRAs were used as standard test surfaces for 2D MTF calibration of the MicromapTM-570 interferometric microscope with all available objectives. The effects of fabrication imperfections on the efficiency of calibration are also discussed.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- Advanced Light Source Division
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 985733
- Report Number(s):
- LBNL-3689E
- Country of Publication:
- United States
- Language:
- English
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Calibration of the modulation transfer function of surface profilometers with binary pseudo-random test standards: Expanding the application range
Calibration of the modulation transfer function of surface profilometers with binary pseudo-random test standards: expanding the application range
Related Subjects
CALIBRATION
DEFECTS
DISTRIBUTION
EFFICIENCY
FABRICATION
MICROSCOPES
MODULATION
MTF
OPTICS
PSD
SPECTRAL DENSITY
TRANSFER FUNCTIONS
calibration
error reduction
fabrication tolerances
interferometric microscope
metrology of x-ray optics
modulation transfer function
power spectral density
surface metrology
surface profilometer