Fabrication of the moving liquid mirror (MLM) spatial light modulator in a standard CMOS-process

Spatial light modulators (SLM) with addressing through a silicon backplane are gaining importance as microdisplays, for pattern generation in direct-writing systems and for several other applications. The use of CMOS technology has lead to small devices with a high grade of integration. With the focus on direct-writing systems for photolithographic patterning we have developed two micromechanical actuator technologies for SLMs with silicon backplane. Here, we report on a third technology that employs an oil film on a mirror as micromechanical actuator. The principle of operation is explained and fabrication is described in detail. Demonstrators with 256x256 pixels have been fabricated with 16µm and 20 µm pixel size. Photographs of programmed images are presented. Measurement of passive devices demonstrated a contrast ratio of 43:1 and a switching time of below 5ms.