Static and Dynamic Optical Metrology of Micro-Mirror Thermal Deformation

摘要

Metrology of MEMS can provide feedback for accurate modeling of thermal-mechanical behavior and understanding of thin film properties. Towards this end, measurements of the thermal-mechanical response of a micro-mirror design have been performed using interfer-ometry. The thermal mechanical response of a 500 μm diameter mirror is induced with spot heating using a 100μm diameter infrared laser at optical powers up to 1.5 W. The transition between elastic and plastic deformation is observed. Amplitudes of elastic and plastic deformation up to 120 nm and 3 μm are measured, respectively. Optical heating is then cycled in the elastic regime, permitting a novel application of stroboscopic interferometry. Results indicate that heating and cooling of the micro-mirror occurs over approximately 2.2 ms, as measured with a temporal resolution of 0.14 ms. Deformation amplitude is proportional to optical power, and depends on micro-mirror surface coating.