Abstract: A method is described for producing at least one small opening (10) in a layer on a substrate (1), in particular a semiconductor substrate. The substrate (1) is provided on the upper side (2) with at least one tapering recess (6), which has a tip portion (4) and side walls (5), and the upper side (2) of the substrate (1) is covered at least in the region of the recess (6) with a layer (7) made of an etchable material. According to the invention, the opening (10) is produced from the upper side (2) by selective opening of the layer (7) by means of an anisotropic plasma etching method which is matched to the material of the layer (7), the material, the etching gases and the etching parameters being chosen such that in the region of a tip portion (9) of the layer (7), which tip portion (9) lies on the tip portion (4) of the substrate (1), a greater etching rate is produced than in the region of side walls (8) of the layer (7) which lie on the side walls (5) of the substrate (1).

Abstract: The invention relates to a method for producing an aperture (10) in a semiconductor material (12) comprising the following steps: Preparing a semiconductor wafer (14), for example, a (100)-oriented silicon wafer having an upper surface (16) and a lower surface (18); producing a cavity (20) with a side wall (22) in the upper surface (16) of the semiconductor wafer (14) by partially etching said upper surface (16), whereby the cavity (20) comprises a closed bottom area (24) which faces the lower surface (18) and which preferably has, in particular, a convex or, in particular, a concave corner or edge or a curvature of this type.