Electroplated Ni microcantilever probe with electrostatic actuation

Electrostatically-driven Ni curl-up microcantilever probes, which can be applied to new MEMS probe cards with contact-switching function, have been developed. MEMS probe cards are requisite to higher pad-density and smaller pad-pitch chips, and are effective in high frequency testing. If a probe card consists of an array of actuator-integrated microprobes, it could be applied to next-generation testing, for instance, a new wafer-level test/burn-in. This can be achieved as the microprobes can be used for the direct switching of the contact to reduce the number of the I/O lines of the probe card. We have designed arrays of Ni curl-up microcantilevers with a rolling-contact touch-mode electrostatic actuator and developed a micromachining process which includes the electroplating deposition of two layers having different internal stress and etching of the Al sacrifice layer. The fabricated cantilevers with a thickness of 1.0 μm and a width of 50 μm have successfully been driven at a pull-in voltage of approximately 100 V. From the disconnection force of the fritting contact between a Ni probe and an Al film, it is estimated that the fritting contact could be disconnected by applying voltages less than 100 V.