Accelerated aging of the digital micromirror device using full custom electrostatic control

Stiction and friction are integral to the dynamic operation of many Microelectromechanical(MEMS) and a comprehensive approach is needed to develop surface coating systems that take into account the fabrication, packaging and operational parameters. The operating environment is also vital for device performance and durability. Texas Instruments' Digital Micromirror Device™ (DMD™), one of the commercial MEMS, is used as a media to develop a testing system for quantitative understanding of stiction and friction properties. The DMD™ has several measurable parameters aiding in the determination of stiction and friction as a function of controllable variables. This paper discusses the development of custom testing system using the DMD™ for stiction studying. A custom control solution is designed and implemented to actuate the DMD™ and accelerate the aging of the lubricant coat. An optical system and allied software are also developed to analyze mirror states. Stiction quantification is carried out by supplying variable voltage reset pulses to initiate release in stuck mirrors. Measurement results indicate that the mirror performance degraded with scrubbing time. Critical parameters like the resonant operating frequency and hinge memory sag effects are also discussed. Knowledge gained through this study can be applied to better understand stiction in other MEMS.