Fabrication of accelerometer using single-step electrochemical etching for micro structures (SEEMS)

This paper presents a new wet etching technique for micromachining called SEEMS (Single-step Electrochemical Etching for Micro Structures). An accelerometer structure can be achieved using this SEEMS process. However, some problems which are involved in the SEEMS process had to be solved. The two main problems are: firstly, over etching can be seen at the clamping point of freestanding beam, and secondly, from the theoretical point of view, it is difficult to remove large region or to make one hole in a large area. These problems can be considerably reduced by improved mask layout and perforated mass supported by single cantilever can be achieved. Additionally, new initial pit formation is demonstrated to make structures which are free from crystal orientation of silicon substrate.