A novel semi-SOI fabrication process for integrated 3D micromachining

This paper presents a novel fabrication process (semi-SOI) for 3D silicon micromachining, as an alternative to SOI technology. The process starts with a standard silicon wafer. DRIE cavities are etched into the back side of the wafer. Then a support layer is deposited into the cavities, so that later the DRIE etching on the front side of the wafer can land on it. The presence of this layer presents several advantages, such as avoiding the notching effect, improving the process flexibility and offering additional functionalities. Several microstructures are successfully fabricated to demonstrate the capabilities of this technology.