Pseudo Three-Dimensional MEMS Imaging Using Reflectance Transformation Imaging (RTI) Technique

Abstract

The study of MEMS devices is highly dependent on the information that imaging techniques can provide. There are two main approaches to observe MEMS devices: Optical and non-optical imaging techniques. Although each of the techniques has its own advantages and disadvantages, optical microscopy is of great interest due to its low-cost, accessibility, resolution and the colored images it provides. A critical shortcoming of optical microscopy is the strict viewing direction and lighting angle that result in flat images with no visual representation of MEMS 3D structure that may lead to some confusion in terms of interpreting the topography of MEMS surfaces and their out-of-plane displacements. This thesis aims at enhancing the 2D representation of MEMS devices by capturing a sequence of images at different illumination angles and highlighting the lateral facets, based on the RTI imaging technique, and then creating a sequence of post-processed images. The proposed algorithm offers a rapid, non-invasive, cost-effective and non-contact imaging technique that aims at minimizing the necessity of using other imaging approaches by revealing the 3D aspects of MEMS devices in terms of 2D visualization.