Development of a traceable profilometer for high-aspect-ratio microstructures metrology

A profilometer using a slender silicon cantilever with an integrated tip and piezoresistive strain gauge was developed to traceably characterize the roughness of high-aspect-ratio micro structures. With a width down to 30 μ m and a length of up to 5 mm, the cantilevers enable to measure the roughness profiles inside micro holes with diameters of 100 μ m and less. Three laser interferometers with 1 nm resolution are arranged perpendicularly to each other at the head of the profilometer to provide metrological traceability with a system uncertainty of ±10 nm for the step height and roughness measurements. Finally, successful measurements of the roughness inside a micro hole of 100 μ m in diameter and the profiles at the entry of the micro hole are presented.