Fabrication of a beam-mass structure using single-step electrochemical etching for micro structures (SEEMS)

Abstract

This paper presents a new wet etching technique formicromachining called single-step electrochemical etching for microstructures (SEEMS), which is based on electrochemical etching inhydrofluoric acid. During the etching, the shape of the etched structurecan be controlled by changing the light intensity. Several problemsinvolved in the SEEMS process had to be solved. The two main problems are,firstly, that over-etching can be seen at the clamping point of the freestanding beam and, secondly, it is difficult to remove large areas. Theseproblems can be considerably reduced by an improved mask layout and aperforated mass supported by a single cantilever can be achieved. Inaddition, a new initial pit formation is demonstrated to make structureswhich are free from crystal orientation of siliconsubstrate.