Micromachined thermal multimorph actuators fabricated by multi-users MEMS process

Micromachined thermal multimorph actuators for out-of-plane displacements have been designed and fabricated by multi-users MEMS process (MUMPS) with a post-processing bulk etching step. Micromachined actuators have potential applications in microtransducers such as scanning tunneling microscope (STM) tips, optical scanners, micromirrors and microrobots. The actuator consists of a multilayer micromachined beam constructed of various combinations of polysilicon, oxide and metal layers. Embedded polysilicon wire is used to heat the multimorph to achieve tip deflection. The tip displacement is a function of the actuator design parameters, such as beam material composition, layer thickness and beam length. The maximum tip deflection of 2.5 /spl mu/m with an input power of 40 mW is achieved. The maximum operating frequency of 2.7 kHz is measured by focus laser reflecting method. A design methodology, device fabrication, and device characterization are presented.