Abstract
In this paper, we present a fabrication technique that enables integration of polyimide into MEMS devices with multi-thickness layer structures. The technique is mainly to utilize a specific SOI (silicon on insulator) wafer with embedded pattern of silicon dioxide. An SOI wafer with a 10 micron thick device layer is thermally oxidized to 400 nm thick and patterned. The patterned side is bonded with another conventional silicon wafer. And then the handle layer of the SOI is removed by wet etching. Although the embedded pattern has 400 nm step structure, no pattern deformation takes place. By using this type of SOI wafers, we have developed a 2-dimensional optical scanner. The MEMS mirror has simultaneously achieved a high resonant frequency and a wide scan angle with no failure. Polyimide-based hinges and thin moving inertia, 10 micron thickness, lead to these characteristics.
