title: Manufacture of Micromirror Arrays Using a CMOS-MEMS Technique.
abstract: In this study we used the commercial 0.35 μm CMOS (complementary metal oxide semiconductor) process and simple maskless post-processing to fabricate an array of micromirrors exhibiting high natural frequency. The micromirrors were manufactured from aluminum; the sacrificial layer was silicon dioxide. Because we fabricated the micromirror arrays using the standard CMOS process, they have the potential to be integrated with circuitry on a chip. For post-processing we used an etchant to remove the sacrificial layer and thereby suspend the micromirrors. The micromirror array contained a circular membrane and four fixed beams set symmetrically around and below the circular mirror; these four fan-shaped electrodes controlled the tilting of the micromirror. A MEMS (microelectromechanical system) motion analysis system and a confocal 3D-surface topography were used to characterize the properties and configuration of the micromirror array. Each micromirror could be rotated in four independent directions. Experimentally, we found that the micromirror had a tilting angle of about 2.55° when applying a driving voltage of 40 V. The natural frequency of the micromirrors was 59.1 kHz.
authors.affiliation: Department of Mechanical Engineering, National Chung Hsing University, Taichung, 402 Taiwan; E-Mail:  d9461402@mail.nchu.edu.tw  (P.-H.K.).
authors.forename: Pin-Hsu
authors.initials: PH
authors.lastname: Kao
authors.forename: Ching-Liang
authors.initials: CL
authors.lastname: Dai
authors.forename: Cheng-Chih
authors.initials: CC
authors.lastname: Hsu
authors.forename: Chyan-Chyi
authors.initials: CC
authors.lastname: Wu