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 inspection. With the focus on direct-writing systems for photolithographic patterning we have developed tow 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 256 by 256 pixels have been fabricated with 16 micrometers and 20 micrometers pixel size. Photographs of programmed images are presented. Measurements of passive devices demonstrated a contrast ratio of 43:1 and a switching time of below 5ms.