Design and calibration of a parallel-moving displacement generator for nano-metrology

Abstract

A displacement generator is realized which enables the calibration of a wide variety of displacement-measuring probes, such as probes of roundness testers, roughness testers and stand-alone type scanning probe microscopes (SPMs), in the range of 12 µm with a standard uncertainty below 1 nm. A digital piezo translator (DPT) drives a flat mirror which serves as the calibration platform. This mirror is locked to an elastic, hysteresis-free, monolithic parallel guide. Calibration of the platform displacement is carried out by various methods including tunable and stabilized lasers, Fabry-Pérot interferometry and laser interferometry. The system is calibrated with a standard uncertainty of about 0.1 nm using three independent methods. As an example the calibration of an SPM using 0.5 µm generated steps is shown.

Displacement Measurement

“…Such a system is described elsewhere [98], where it was used to calibrate a displacement generator with a capacitive feedback system with 0.2 nm uncertainty. As a capacitive system can be assumed to have a smoothly varying nonlinear behaviour, discrete steps can be feasibly used.…”

“…For a larger frequency range, the cavity length can be reduced, but this increases the demands on the ability to measure a larger frequency range. With tuneable diode lasers, the cavity length can be reduced to the millimetre level, but this requires different wavelength measurement methods [98].…”

Multiaxis interferometric displacement measurement for local probe microscopy

“…On a small-range scale they may be considered negligible. Nanopositioning stages covering ranges over 1 mm or even several cm represent a very complex problem requiring designs with a sophisticated flexture lever system [12][13][14][15][16] or high-quality guidance reducing the backlash [17,18]. Driving of a large-range stage is a task for motor incorporating the stepping principle.…”

Development of a Silicon-based Nanoprobe System for 3-D Measurements

“…The displacement of the moving surface relative to the platform is determined by an accurate measurement system. Comparable devices have been designed by Wetzels [6] and Haitjema [7,8]. A 1-D calibration set-up can be used along a line in the x-, y-and z-directions.…”