METHOD FOR PRODUCING INSULATION STRUCTURES

摘要

The invention relates to methods for producing insulation structures for micromechanical sensors according to a monocrystalline surface technique. According to known methods, silicon structures defined by deep trenches are etched and the lower side thereof facing the substrate is exposed by a release etch step. The filling of said trenches with a dielectrically insulating material, such as silicon dioxide, enables the silicon structure to be solidly clutched on three sides. The invention is based on the fact that instead of filling trenches, thin-walled silicon is converted into an electrically non-conductive material. This can be carried out, for example, by means of thermal oxidation of narrow silicon sections previously exposed by trenches. In a minimal configuration, two trenches (holes) must be etched per section with the desired structural depth. The interlying silicon section must be narrow enough to be able to be fully thermally oxidised.