Scaling torsional cantilevers for scanning probe microscope arrays: theory and experiment

An array (12/spl times/12) of microelectromechanical probe tips with integrated actuators and capacitive sensors for scanning probe microscopy has been designed, fabricated, and characterized. Each array element consists of a single crystal silicon tip on a torsional cantilever with out-of-plane interdigitated electrode capacitors. The size of each array element is about 150 /spl mu/m by 150 /spl mu/m with a tip-to-tip spacing in the array of 200 /spl mu/m. Given these dimensions, the packing density of the devices is about 2500 units/cm/sup 2/. The out-of-plane torsional design allows for significant improvement in performance (larger tip displacement and increased sense capacitance) and a higher density of devices per unit area as the minimum feature size (MFS) decreases.