Miniaturization and batch fabrication of two-axis water-immersible scanning mirrors

This paper reports a new micromachined two-axis water-immersible micro scanning mirror using BoPET (biaxially-oriented polyethylene terephthalate) hinges. A new fabrication process based on lithography, wafer-bonding, and reactive ion etching on a hybrid silicon-polymer substrate was developed to enable high-resolution patterning, miniaturization and also batch fabrication capability. For demonstration, a prototype scanning mirror was designed, fabricated and tested. Its overall size was reduced to 5 x 5 x 5 mm(3), which is comparable to that of a typical silicon-based micro scanning mirror. The testing results show good raster scanning performance. This approach could enable the miniaturization and batch fabrication of water-immersible scanning mirrors for different scanning optical and acoustic imaging applications in liquid environments.