Development of advanced second-generation micromirror devices fabricated in a four-level, planarized surface micromachined polycrystalline silicon process

This paper describes the design and characterization of several types of micromirror devices to include process capabilities, device modeling, and test data resulting in deflection versus applied potential curves and surface contour measurements. These devices are the first to be fabricated in the state-of-the-art four-level planarized polysilicon process available at Sandia National Laboratories known as the Sandia Ultra-planar Multi-level MEMS Technology (SUMMiT). This enabling process permits the development of micromirror devices with near-ideal characteristics which have previously been unrealizable in standard three-layer polysilicon processes. This paper describes such characteristics as elevated address electrodes, various address wiring techniques, planarized mirror surfaces using Chemical Mechanical Polishing (CMP), unique post-process metallization, and the best active surface area to date.