Local probe microscopy with interferometric monitoring of the stage nanopositioning

Abstract

We present a system of positioning and interferometric monitoring of a sample position for measurements and calibration in the nanoscale in metrology. The positioning is based on a three-axis stage which allows replacing scanning by the probe of an atomic force microscope with a system with full interferometric displacement measurement. A stage with 200 µm × 200 µm of horizontal travel extends also the microscope range. The stage allows positioning with sub-nanometer resolution in all three axes under a closed loop control with position detection via capacitive sensors. Interferometric system monitoring all six degrees of freedom of the stage ensures full metrological traceability of the positioning to the fundamental etalon of length and improves resolution and overall precision of the displacement monitoring.