Ti-Ni shape memory alloy film cantilever actuator for micro-probing

This paper describes novel MEMS probe card device, which is composed of silicon (Si) cantilever beams actuated by titanium-nickel (Ti-Ni) shape memory alloy (SMA) films. Since Ti-Ni SMA film can yield a higher work output per unit volume, Ti-Ni film-actuated Si cantilever beam is expected to be a MENIS probe card device providing large contact force between probe and electrode pad. The developed cantilever beam produces a contact force by not only cantilever bending in contact but also the shape memory effect (SME) of Ti-Ni film arising from Joule's heating. The SME of Ti-Ni film containing Ti of 50.5 atomic (at.) % to 53.2 at. % can generate an additional contact force of 200 mu N on average under applying an electric power of 500 mW to the film. Ti-Ni film-actuated Si cantilever beam would be a key element for successful MEMS probe card with larger contact force and smaller size.