Research Of A Novel Electrotheromal Microactuator And Bistable Structure

Owing to the advantages of electro-thermal micro-actuator, such as large output torque, low driving voltage, suitable for microminiaturization and easy to integration, two kinds of electro-thermal micro-actuator are designed and fabricated. In order to reduce the power consumption and decrease the response time, a novel tensional/cantilever bistable structure with magnetic circuit is designed. And we focus on the bi-layer electro-thermal micro-actuator which consists of alumina film and nickel metal. At last, the two devices are integrated as a combined structure and testing process is conducted.In this study, two kinds of electro-thermal micro-actuator are designed, one is the novel polymeric out-of-plane electro-thermal micro-actuator embedded with nickel metal, and the other is the electro-thermal micro-actuator based on aluminum. There are also two structures in aluminum based electro-thermal micro-actuator: the tri-layer electro-thermal micro-actuator consist of SU8, alumina film and nickel metal; and the bi-layer electro-thermal micro-actuator consist of alumina film and nickel metal. The mechanical properties of the electro-thermal micro-actuator have been simulated by ANSYS. Then the predetermined parameters have been optimized according to analysis results. Series of problems are investigated and resolved, such as sputtering, etching alumina film, etching copper sacrificial layer and so on. Then these processes have been integrated to fabricate the electro-thermal micro-actuator samples. Through comparison, the bi-layer electro-thermal micro-actuator which consists of alumina film and nickel metal has the higher production yield due to the easily controlled process, and simultaneously the SU8 layer and nickel passive layer are seldom separated. The tests results show that the displacement is 46um with the input current 80mA.Here, a novel bistable structure is designed to realize the latching function and reduce the power consumption. We design three kinds of tensional/cantilever bistable beams. According to the multi-material 3D MEMS process technology, the samples of three kinds of tensional/cantilever bistable beams are fabricated. And the surface morphology and dynamic properties of three kinds of torsional/cantilever beams is characterized by SEM and Veeco repectively. At last, the bi-layer electro-thermal micro-actuator and the novel tensional/cantilever bistable structure have been integrated. After conformity of processing technology, the combined structure has been successfully prepared. Through dynamic testing, the combined structure can realize the bistable function, and the response time is about 20ms.