Modeling and performance of a magnetic MEMS wiping actuator

A MEMS magnetic actuator microswitch has been fabricated which, in addition to the primary cantilever bending, exhibits a secondary wiping motion during overdrive. A self-wiping action is desirable in a microswitch because it can help clean the contacts and prevent contact fusing. The wiping action occurs as a result of lowering the total energy of the actuator system with increasing external magnetic field H _o. The actuator is batch fabricated using standard microelectronic processing, and the ferromagnetic permalloy is patterned lithographically into long narrow strips on the actuator to maximize the magnetic torque generated for a given actuator size. The total wiping distance for a 1000-mum-long switch was 50 mum with magnetic fields from 10 to 100 mT. A first-principles physical model has been derived for the equilibrium and dynamic behavior of the device, as well as discrete changes in position due to frictional effects