CALIBRATION OF STEP HEIGHT STANDARDS FOR NANOMETROLOGY USING INTERFERENCE MICROSCOPY AND STYLUS PROFILOMETRY

Calibration of step height standards used for the vertical calibration of such topography measuring instruments as styli, atomic force microscopes, and tunneling microscopes is described in this article. The calibration uncertainty of a commercial high-resolution contact stylus instrument is compared with the calibration uncertainty of two types of interference microscopes. One of them is a phase-shifting Mirau interference microscope, the other is a Linnik interference microscope. The fringe pattern of the latter can be evaluated visually using an Abbe comparator, and automatically using the spatial carrier fringe-pattern analysis. The calibration uncertainties of the mechanical and optical instruments were investigated. Measurements were performed with very smooth rectangular-shaped groove standards with depths from 3 mu m to 60 nm. The estimated and experimental uncertainties were compared.