Measurement of micro-geometry using white-light interferometry and confocal microoptical sensors - Measuring principles, applications, limitations

摘要

Optical methods, especially white-light interference microscopy and confocal microscopy, represent the state-of-the-art in 3D-measurement of workpieces with microscopic features. Nevertheless, MEMS and MOEMS often show geometries with tilted or curved nearly specular surface areas or height step structures, which are characterised by low tolerances and consequently are to be measured very accurately. Therefore, not only high accuracy is required but also highest reliability and flexibility of the measuring systems. As it is shown in this contribution, extended and improved signal processing strategies, the use of different wavelength regimes, and the consequent miniaturization of sensor elements are some approaches, which may lead to a broader range of applicability of optical methods in micro-systems technology and an improved reliability of optical measurements.