Thickness measurement in ultrathick multilayer microstructures

Microparts are more and more mass products and quality assurance becomes an important factor in manufacturing. Based on a new optical principle, a tool was developed and tested which is well suited for easy non-destructive measurements at microstructures as well as for measurement at transparent layers. Thickness measurement of ca. 1 mm ultrathick photoresist layers on non-patterned high-reflective gold surface was demonstrated. As well, measurement of multi layer systems consisting of each several hundred micrometers thick transparent layers was verified at capped microfluidic channel structures.