Mechanical and electrical failures and reliability of Micro Scanning Mirrors

We present results of failure and reliability investigations on silicon Micro Scanning Mirrors. The electrical insulation resistance, mechanical shock resistance and long-run stability were characterized. By design optimization including a combination of filled and open insulation trenches we achieve an average insulation resistance of more than 10 GΩ at 20 V. The experimental data from devices with an eigenfrequency between 270 Hz and 350 Hz show that they withstand a shock acceleration of more than 6900 g in 3 axes when not operated and of 2500 g at least when operated. This remarkably results are due to several optimized design aspects. In long-run tests with high deflection angles the springs were exposed to a torsional stress of up to 1.5 GPa for more than 1.6×10⁹ periods. No failure or significant change of the eigenfrequency was observed.