Study On Process Of Double-deck Microgear Mold Insert Based On UV-LIGA Technology

With the development of the MEMS,the requirement of the micro-product are increasing.The micro-product made of micro-injection molding technology leads a very important place in the MEMS field,it not only has high precision of molding,good stability,low cost,easy shaping but also good physics and mechanics features.The process quality of the micro-cavity is the foundation of the micro-injection molding,and directly influence the shape,dimensions and precision.Compared to LIGA,UV-LIGA has the advantage of the low cost and short period.But UV-LIGA has some shortage of process depth,aspect ratio and vertical sidewalls.Therefore,the research for improving the capability of the process aspect ratio and vertical sidewalls has a great significance.UV-LIGA technology was adopted to fabricate the insert of double-deck microgear mold on the indium tin oxidation (ITO) glass substrate in this paper.First,through analysis of the back-plate-growth method and the no-back-plate-growth method,the fabrication scheme was made,including the selection of the substrate material,the structural design of the double-deck microgear cavity,the process flow,the design and fabrication of the mask.Second,the relation between the coating thickness and the rotate speed on the ITO substrate was studied by the experiments.Utilizing the orthogonal optimization method,the impacts to the photoetching quality caused by the time of prebake, exposure,post bake and the rate of the cooling were presented,and the technological parameters of single-deck SU-8photoresist were optimized.The two electroplate liquids were separately adopted to study the electroplate characters on the ITO substrate.Finally,The feasibility of the fabrication process flow of the double-deck microgear mold insert was confirmed through the experiment,and the technological parameters were optimized.In the process of the double-deck microgear mold insert,the problems of photoetching and micro-electroforming were discussed with the theory analysis,and the effective actions were adopted to improve the quality of the double-deck microgear photoresist and solve some problems of micro-electroforming.