A circular micromirror array fabricated by a maskless post-CMOS process

作者：Cheng YC; Dai CL^*; Lee CY; Chen PH; Chang PZ

来源：Microsystem Technologies, 2005, 11(6): 444-451.

DOI：10.1007/s00542-004-0486-0

This work studies the fabrication of a circular micromirror array by the standard 0.35 mu m SPFM (Single Polysilicon Four Metals) CMOS (complementary metal oxide semiconductor) process and a maskless post-process. The advantages of the post-process are its compatibility with conventional CMOS process and this method provides a way to designer to quickly construct micromachined structures using the standardized procedures. The mentioned circular micromirror array that contains 10 x 10 micromirror switches is integrated with a 1 x 8 de-multiplexer control circuit and a four-stage charge pump on a chip. The radius of each micromirror is about 25 im, and the gap from the bottom electrode to the top mirror plate is about 5 mu m. The micromirror array is actuated using an electrostatic force. Simulated results show that the micromirror has a tilting angle of around 9 degrees at a driving voltage of 30 V. The root-mean-square roughness and the average roughness of the mirror surface are measured at 15.31 nm and 12.58 nm respectively. In addition, the first and the second mode of natural frequency of the micromirror switch are around 492 KHz and 508 KHz, respectively.

• 出版日期2005-5