Microassembly process to fabricate a microoptoelectromechanical systems scanning mirror with angular vertical comb electrodes

作者：Jun Min Ho^*; Moon Seunghwan; Lee Jong Hyun

来源：Journal of Micro/ Nanolithography, Mems, and Moems, 2013, 12(1): 013006.

DOI：10.1117/1.JMM.12.1.013006

• micromirror
• optical scanner
• microoptoelectromechanical systems scanner
• angular vertical comb
• microassembly
• tilting pillar
• polymer (SU-8)

We present a simple microassembly technology that easily realizes angular vertical combs for a microoptoelectromechanical systems scanner. The scanner is composed of a device section with comb electrodes and a tilting section with four tapered pillars. During the microassembly process, two tilting pillars push down the levers so that the comb electrodes connected with the micromirror are tilted; the other two alignment pillars fit into the alignment holes of the device section, which is fabricated via a deep reactive ion etching process of a silicon-on-insulator wafer. The tilting section is fabricated through a series of anisotropic wet etching of a (100) silicon wafer and patterning processes of SU-8, which is robust enough to ensure repeatability of the initial tilted angles of the movable comb electrodes. The pull-in investigation function is analyzed through a numerical estimation to obtain a large scan angle with stable behavior. The fabricated microscanner shows an optical scan angle of up to 4.23 deg at 90 V in the static mode and stable actuation of up to 11.3 deg at a resonant frequency of 2.87 kHz. The roughness of the mirror surface is less than 10 nm, which will have a negligible effect on imaging quality. The initial tilted angles in the microassembly process showed high repeatability within 10% error.

• 出版日期2013-3