Manufacture of Micromirror Arrays Using a CMOS-MEMS Technique

• Main Authors: Chyan-Chyi Wu, Ching-Liang Dai, Cheng-Chih Hsu, Pin-Hsu Kao
• Format: Article
• Language: English
• Published: MDPI AG 2009-08-01
• Series: Sensors
• Subjects: micromirror array; microactuator; CMOS-MEMS
• Online Access: http://www.mdpi.com/1424-8220/9/8/6219/

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.