Application of capillary forces and stiction for lateral displacement, alignment, suspension and locking of self-assembled microcantilevers

摘要

We report the surface-tension-powered self-assembly ( displacement, alignment, pulling down and locking) of microcantilevers. Capillary forces-assisted displacement is realized by compression of four arrays of springs linked to the opposite lateral sides of the cantilevers. After in-plane translation along the initial cantilever orientation, the microstructure is pulled down and locked on the substrate by stiction. Spring and capillary forces are described with a simple analytical model. Complete self-assembly occurs when the layout of the whole system ( the cantilever with its traveling spring structure, the surrounding area and the local distribution of the liquid) is well designed. We show that the presence of a water meniscus trapped at a step edge in the vicinity of the tip end of a microcantilever could lead to stiction failure before traveling of the structure. Small beams ( 6 mu m long) protruding over step edges were fabricated by adding a mechanically assisted displacement step ( with a microneedle) to the self- assembly experiment.