Method for manufacturing a micromechanical sensor element

Abstract

Described is a method for manufacturing a micromechanical sensor element and a micromechanical sensor element manufactured in particular using such a method which has a hollow space or a cavity and a membrane for detecting a physical variable. Different method steps are performed for manufacturing the sensor element, among other things, a structured etch mask having a plurality of holes or apertures being applied on a semiconductor substrate. Moreover, an etch process is used to create depressions in the semiconductor substrate beneath the holes in the structured etch mask. Anodization of the semiconductor material is subsequently carried out, the anodization taking place preferably starting from the created depressions in the semiconductor substrate. Due to this process, porous areas are created beneath the depressions, a lattice-like structure made of untreated, i.e., non-anodized, substrate material remaining between the porous areas and the depressions. This lattice-like structure extends preferably from the surface of the semiconductor into the depth. The etch mask for creating the depressions may be removed, optionally prior to or subsequent to the anodization. A temperature treatment is carried out for creating the hollow space and the membrane in the semiconductor substrate which forms the sensor element. During this process, the hollow space is created from the at least one area that has been rendered porous beneath a depression and the membrane above the hollow space is created from the lattice-like structure by rearranging the semiconductor material.