MEMS Fixtures for Handling and Assembly of Microparts

Fixtures are used to locate and hold parts during automated inspection, machining, or assembly. Microelectromechanical systems (MEMS) are tiny devices built in batch processes derived from integrated circuit fabrication. We describe a design for an array of MEMS microfixtures for parallel inspection, transport, and assembly of microfabricated parts. In a microfixture array, parts are brought near the fixture by random motion provided e.g. by vibratory agitation. The fixture clamps actively close when the parts enter the fixture. In large future fixture arrays, electrostatic or optical sensors integrated into the fixture cell can trigger this clamping function. Each cell operates autonomously and no global control is necessary. We fabricated a prototype cell consisting of two upfoldable fixture walls and a bimorph thermal actuator using a standard CMOS process. This approach allows batch fabrication of large numbers of cells on a single silicon wafer, as well as easy integration of sensors and actuators that autonomously close each cell when filled.