Sub-micron LIGA process for movable microstructures

The feasibility of making movable metal microstructures with lateral dimensions in the sub-micron range and aspect ratios of up to 100 was demonstrated. These structures were manufactured by X-ray lithography in resists approximately some ten micrometers high and with electroplated nickel. The small resist height, compared to deep X-ray lithography, allowed softer X-rays and lower absorbers on the mask to be used. Therefore, no intermediate masks are needed and shorter beam times are possible. The small overall dimensions of devices with sub-micron dimensions even with very high aspect ratios allow a much larger number of devices to be arranged on a wafer. This opens up a way to cost effective manufacturing of movable microstructures on top of electronic circuits when the performance of the device is determined by the aspect ratio, not by its overall size.