Micro-optics in advanced optical metrology

Abstract

An accurate characterization is a very important topic in a wide range of MEMS/MOEMS applications and crucial for their fabrication process. Standard characterization is performed with bulk measurement system. Usually, a high resolution optical systems measure one structure at a time and scan the measurement samples from structure to structure. These systems are not well suited to the production control of microsystems, where several thousands of structures are fabricated on the same substrate simultaneously. The paper presents new approaches using microoptics and micromachining to overcome the large ratio of wafer size to feature size in the testing step of production. The refractive and diffractive microoptical components, often fabricated on glass wafer, allow to create arrays of integrated measurement instruments. This work focuses on a new full-field optical concept for parallel, high volume M(O)EMSs' testing. The use of diffraction gratings for the realization of an array of integrated interferometers allows to create compact device with 25 measurement channels. The design of measurement platform and interferometer array, its assembly and the validation measurement results, are discussed in details. The functionality of system includes static and dynamic in-line characterization of MEMS.