Quality Inspection of Microtopographic Surface Features with Profilometers and Microscopes

Abstract

With the increasingly widespread adoption of micromanufacturing solutions and with the production of a growing number of artifacts defined at the microscopic and submicroscopic scales, increasingly smaller geometries need to be verified for quality assurance. The study of precision at micro and submicro scales is gaining considerable interest: relevant issues pertain to how to define allowable geometric error on parts of such small sizes (e.g., semiconductor products, microelectromechanical systems, other microcomponents) with proper dimensional and geometric tolerances, and how to measure them. This work addresses the specific problem of assessing geometric error associated with micromanufactured surface features. Three-dimensional digital microscopes and profilometers for microtopography analysis are increasingly being adopted for such a task, owing to their suitability to operate at very small scales. However, this raises several challenges, as three-dimensional microscopes and profilometers have traditionally been used in different application domains, and are mainly aimed at the inspection of surface finish; new modes of operation must be identified which take into consideration such peculiarities. Both families of instruments need to be closely investigated, and their main constraints and benefits dissected and analyzed to assess their adaptability to the new task of assessing geometric error on micromanufactured parts or surface features.