Fabrication Process Of Micro Electrical Switch And Copper Micro Grating

With the rapid development of MEMS technology,metal micro devices which have the advantages of small volume,low consumption of energy and high reliability have been widely used in the fields of military,medical and precision instruments.At the same time,the fabrication methods of metal devices based on photolithography and precision micro-electroforming have been widespread concerned.In this paper,the structure and dimension size of the micro electrical switch were determined firstly and the processing difficulties of the switch based on lithography and electroforming was studied at the same time.Then,the fabrication processes of nickel micro switch were carried out.The fabrication processes of micro grating were carried out by referencing the process of micro switch.According to the existing fabrication methods of micro switch and micro grating,the fabrication methods of photolithography and micro electroforming on the metal substrate were determined.The overall structure of the switch was determined through selection.Combing the characteristics of fabrication process and the micro structures,the difficulties encountered in fabrication process were studied firstly.To solve the problems of interfacial bonding failure in the process of fabrication,the methods of optimizing switch structures and electroforming processes were used.The problems of SU-8 development of high aspect ratio films were solved by introducing the ultrasonic assisted development method.The appropriate exposure parameters were obtained through the contrast experiments of exposure.The research on the fabrication of metal micro switch was carried out based on the conclusion and methods researched firstly.The stainless steel plate was adopted as the substrate and a nickel micro electrical switch with high aspect ratio was fabricated by laminating lithography,micro electroforming,copper sputtering and wet etching processes.The fabrication error were analyzed theoretically,the method of “width error compensation” were introduced to reduce the error.The overall size of the switch is 4000*3900*360?m,the minimum size is 20?m,the maximum aspect ratio is 14:1.The micro switch was packaged by leadless chip carriers.The width sizes of key structures in micro switch were measured by tool microscope and the dynamic performances were tested by rotation and dropping hammer testing platform.The results showed that the fabricated micro switch meet the requirements.The fabrication research of micro grating with high aspect ratio structure was carried out after combing the characteristics of fabrication process and micro grating.The copper plate was adopted as the substrate and the micro-grating was fabricated by combing the process of lithography,electroforming.The SU-8 photoresist was removed by vacuum annealing in high temperature.The cycle width of micro grating is 130?m,the overall size of the convex platform is 2400*65*220?m.The fabrication size and roughness of the working surface were measured by tool microscope and Zygo surface profiler.The results showed that the relative error of the dimension is less than 2% while the roughness is less than 0.03?m.