A Micro Electro-Mechanical System design and manufacture considering fabrication error

MEMS fabrication technology has very high fabrication precision, but there is still fabrication error inevitably like any other fabrication technology. We adopt LIGA technology to fabricate a Micro Electro-Mechanical System. From the analysis of fabrication process, the fabrication errors of MEMS part consist of mask and LIGA fabrication error. The designed MEMS parts can be divided into metal and PMMA part. Synthesizing the mask and LIGA fabrication errors, the errors of metal entity and cavity structure are -10.5 mu m similar to +5.5 mu m and similar to 5.5 mu m similar to +10.5 mu m. The errors of PMMA entity and cavity structure are -5 mu m similar to +10 mu m and -10 mu m similar to +5 mu m. Analyzing each situation, the most interference dimension of the four assembling situations is 20 mu m. According to the conclusion, we leave 10 mu m margin for each of the two parts assembling together. So the whole margin of the two parts is 20 mu m, which ensures that the two MEMS parts can be assembled reliably. Measuring the fabricated MEMS part with a micro precision measurement equipment indicated that the fabrication error was in the scope of theoretical analysis. The fabricated LIGA MEMS system can be assembled reliably and the centrifugal experiment indicated that the motional part worked well and moved to the destination position.