It is important for a micro-mirror surface to have high optical characteristics. As a conventional micro-mirror surface of a poly-Si structural layer has poor reflectivity, it needs a metal coating layer to improve it. However, as the metal layer sputtered on the poly-Si structural layer is often attacked by subsequent process steps, the adhesion of the metal layer needs to be improved. We report on the improvement of the adhesion and the final optical characteristics of a micro-mirror switch. The improved metal layer sputtered is strong enough to endure the rest of fabrication process. Various dry-etch chemistries for poly-Si structural layer and wet-etch chemistries for sacrificial layer are compared to preserve the metal surface quality along the fabrication process. Improved dry-etch rate of 800 nm/min with vertical etch profile was obtained from SF6 plasma gas. It is now possible to fabricate a simple and efficient MEMS micro-mirror switch in a batch process. (C) 2003 Elsevier Science B.V. All rights reserved.