Fabrication and characterization of 3D integrated 2 DOF Micromirror Arrays for excessive thermal loads

This paper reports a high fill-factor (>90%), 2-dimensional analog micromirror array designed specifically for very high, optically induced thermal load applications. Each pixel can attain a mechanical DC rotation angle of ±4 degrees around any arbitrary axis with 170V excitation. The maximum temperature rise on the mirror surface with 7 KW/m2 thermal load under 1 Pa ambient pressure is below 230 °C. A detailed assessment of the fabrication process –including the poly-Si vertical electrodes, wafer level mirror bonding, and copper electroplating of structural layers–, and characterization methodology is presented with experimental results.