Modeling And Simulations Of BOSCH Processing Technology Using String Algorithm

MEMS is developed based on IC technology. With twenty years of rapid development, it has become an interdisciplinary, which involves different fields as electricity, thermology, mechanology and magnetology. MEMS is widely used in material science, biomedical, aerospace, automotive industry and other areas, and it is always the focus of the science and technology research. Micromachining technology is the basis of research and manufacture of MEMS devices, mainly including etching, deposition, LIGA and other processes. Compared with IC process, MEMS manufacture focus on the three-dimensional structure and the surface topography in micro size. Currently, being different from standard IC process, MEMS technology research mainly dependents on the experience and repeatedly experiment, which will inevitably lead to the waste of resources, extension of production cycle and increase in production costs. Therefore, the further development of MEMS is hindered. In the field of MEMS CAD, there has been some research on the two-dimensional simulation. However, three-dimensional simulation is still facing many challenges of high occupancy of CPU and memory, imperfect algorithm, low simulation speed and low simulation accuracy.With the development of MEMS device function, the design and process of its structures have become more complex. High aspect ratio etching has caused the extensive concern as a key technology for MEMS. BOSCH process is generally used in the MEMS process. Presently, there is research about single processing technology of MEMS manufacture simulation, but not the three-dimensional modeling for BOSCH technology for composite process simulation. Although some simple processes have been involved in some commercial software referred in this dissertation, they mainly introduce the methods used in software and rarely describe the process modeling method and simulation process. Firstly, several existing simulation platform are introduced and compared in this dissertation. Then, study on several 3-D surface evolvement algorithm is done and its advantages and feasibility are demonstrated. Furthermore, three-dimensional line algorithm model is optimized and used for the modeling of BOSCH process. At last, C language is used to realize the simulation programs and Matlab is used to export the simulation results.In BOSCH process, the shape, size and process duration of the etching window impacts the aspect ratio and sidewall smoothness of processing results. The simulation results in different etching window are obtained by changing the initial conditions and simulation cycle. Finally, the simulation results are analyzed and shown the accordance with experiments and predictions. Therefore, the accuracy of the algorithm and model is verified and the research basis for further study on the etching process (such as real-time simulation) of MEMS CAD is provided.