CONSIDERATIONS REGARDING THE USE OF SU-8 PHOTORESIST IN MEMS TECHNIQUE

Microelectromechanical systems (MEMS) represent the technology of microscopic devices. In this domain, photolithography is the most common method in order to obtain MEMS structures. The photoresist is the key element for microelectronic and MEMS technology. SU-8 is one kind of negative photoresist, used basically for microfluidics. This paper presents experiments of SU-8 etching in O2/SF6 and Ar/SF6 plasma. Monocrystalline silicon wafers with 3" diameter were used, which had native oxide preserved. The SU-8 was spin-coated on the wafers with a thickness of approximately 100 μm. The experiments were made with varying the gas flow rate and the pressure in the reactor. The etching depth and the underetching gave different values every time.