Mems Micro-deformable Mirror Test And Process Anti-adhesion Technology

Due to the advantages of high integration and mass production, surface-micromachined segmented deformable micromirrors driven by electrostatic force have become the focus of research among various types of micromirrors. However, they suffer from the problem of stiction, so, how to control the stiction for the successful manufacturing of MEMS segmented deformable micromirrors has become a difficult problem.Firstly, comprehensive researches on the source of adhesion, measurements and controls of stiction have been done. As a result, the micromirrors will be adhesioned to the underlying substrate, because of the large area of segmented deformable mirrors and surface tension of water, after the micromirrors are dried, if the elastic forces can not overcome the surface tention.Secendly, several different procedures commonly used to rinse and dry released micro cantilever beams are compared: evaporation drying with deionize water or methanol, sublimation drying with t-butyl alcohol. This study reveals that the maximum detachment length of cantilever beams increases as the beam width increases for the cases of evaporation and sublimation drying. At the same time, the detachment length of cantilever beams released by sublimation up to 650 micrometers without stiction, as compared, releasing cantilevers by evaporation with methanol is only about 140 micrometers without stiction.Thirdly, the potential of self-assembled monolayer(SAM) coatings for the purpose of adhesion reduction in MEMS and surface roughed have been investigated. Two types of SAM coatings, such as FDTS and OTS were applied to the micromachining, the results have revealed that the SAM coatings not only prevent released stiction but also in use stiction.Finally, precise measurement of micro structures during the design, simulation, fabrication, and evaluation has become very important. And because of the several problems in micromachining the micro segmented deformable mirrors, some advice in this subject are provided such as PSG repleases the conventional sacrifical layer, the improve on release methods, the residual stresses control of polysilicon.