A new MEMS wafer probe card

This work presents a new type of wafer probe card consisting of an array of microcantilevers actuated by bimorph heating to make contact with the contact pads on a device chip during wafer-stage testing. The microcantilevers are meant to be operated either in air or in vacuum. Bending action is created through Joule heating of a bimorph film element on the cantilever. The deflection efficiency d/spl delta//dP ranges from 5.8 to 9.6 /spl mu/m/mW (depending on lever parameters), the force efficiency dF/dP ranges from 1.4 to 5.5 /spl mu/N/mW; maximum controllable (reversible) deflection is in the range of 150 /spl mu/m, and contact resistance to a gold pad is approximately 1 /spl Omega/.