Methods for producing a cavity within a semiconductor substrate

摘要

A method for producing at least one cavity within a semiconductor substrate includes dry etching the semiconductor substrate from a surface of the semiconductor substrate at at least one intended cavity location in order to obtain at least one provisional cavity. The method includes depositing a protective material with regard to a subsequent wet-etching process at the surface of the semiconductor substrate and at cavity surfaces of the at least one provisional cavity. Furthermore, the method includes removing the protective material at least at a section of a bottom of the at least one provisional cavity in order to expose the semiconductor substrate. This is followed by electrochemically etching the semiconductor substrate at the exposed section of the bottom of the at least one provisional cavity. A method for producing a micromechanical sensor system in which this type of cavity formation is used and a corresponding MEMS are also disclosed.

主权项

1. A method for producing at least one cavity within a semiconductor substrate, the method comprising:
carrying out a dry etch process at a substrate surface of the semiconductor substrate in order to form at least one provisional cavity; carrying out a plasma chemical vapour deposition of a silicon oxide at the substrate surface and at cavity surfaces of the at least one provisional cavity; anisotropically etching the silicon oxide at least at a section of a bottom of the at least one provisional cavity; and electrochemically anisotropically etching the semiconductor substrate using an electrochemically controlled pn etching stop, wherein the electrochemical anisotropic etching is effected at least at the section of the bottom of the at least one provisional cavity and extends the at least one provisional cavity in this way, wherein the electrochemical anisotropic etching comprises a first temporal segment, during which an electrical voltage applied to the semiconductor substrate is increased, and a second temporal segment, during which the electrical voltage applied to the semiconductor substrate is kept constant.