S. Ilias, P. Topart, C. Larouche, S. Leclair, H. Jerominek "Design and fabrication of giant micromirrors using electroplating-based technology" Proc. of SPIE, 5715:190-200, 2005
Abstract: Giant micromirrors with large scanning deflection and good flatness are required for many space and terrestrial applications. A novel approach to manufacturing this category of micromirrors is proposed. The approach combines selective electroplating and flip-chip based technologies. It allows for large air gaps, flat and smooth active micromirror surfaces and permits independent fabrication of the micromirrors and control electronics, avoiding temperature and sacrificial layer incompatibilities between them. In this work, electrostatically actuated piston and torsion micromirrors were designed and simulated. The simulated structures were designed to allow large deflection, i.e. piston displacement larger than 10 μm and torsional deflection up to 35º. To achieve large micromirror deflections, up to seventy micron-thick resists were used as a micromold for nickel and solder electroplating. Smooth micromirror surfaces (roughness lower than 5 nm rms) and large radius of curvature (R as large as 23 cm for a typical 1000×1000 μm2 micromirror fabricated without address circuits) were achieved. A detailed fabrication process is presented. First piston mirror prototypes were fabricated and a preliminary evaluation of static deflection of a piston mirror is presented.
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