Research on fabrication of microstructure by using UV-LIGA

With SU-8 photoresist, the technology of UV-LIGA has been developed as an important method of fabrication micro structures. The process consisting of photolithographic and microelectroforming were studied in this paper. Orthogonal experimental design was applied in research. From experiment it can be concluded that the soft bake temperature and time was the key factor of the structure quality. When the photoresist thickness ranged from 120 to 340μm, the soft bake temperature and time was 90°C and 50∼120 minutes, that means the perfect image. The best post expose bake temperature was 85∼95°C with less 40 minutes bake. In order to obtain the suitable parameters of the various thickness photoresist, an artificial neural network (ANN) with 3 layers were built. The ANN was trained based on orthogoality experiment using back propagation algorithm. Compared to the experiment results, the prediction error was less than 2.0%, which proved that the ANN was effective. The characteristics of the microelectroforming process were analysed systematically. The results showed that the mass transfer is the control factors of microelectroforming process. The lithographic and microelectroforming process of the fabrication of high resolute micro structure was optimized.