Large displacement electrostatic micromirror fabricated using solder flip chip bonding

We will report a novel batch transferred micromirror using flip-chip bonding and surface micromachining with large angle displacement. The micromirror system is fabricated through MUMPs (multi-user MEMS processes) and composed of a micromirror, electrodes, fuse-away tethers, and solder joints. Transfer is achieved using temporary fuse-away tethers that suspend the released micromirror. The tethers can be easily broken away when current for fusion is applied. The location alignment between the micromirror and the electrodes can be easily obtained due to solder self-aligned joints. The micromirrors and tethers are designed based on electrical-mechanical combined analyses and heat transfer simulations. In addition, design optimization is carried out to decrease the driving voltage. After the optimization, a large displacement angle of 5 degrees is achieved at a driving voltage of 70 volts.