Method for anisotropic plasma etching of semiconductors

A method of anisotropic etching of structures in a semiconductor body, including recesses in a silicon body exactly defined laterally by an etching mask, comprising the step of etching the semiconductor body by using a plasma, wherein an ion acceleration voltage is applied to the semiconductor body between the plasma and the semiconductor body at least during an etching step, wherein the etching step is subdivided into at least two etching segments between which the ion acceleration voltage applied is modified each time, and wherein the ion acceleration voltage applied is generated by a high-frequency AC voltage applied to the substrate electrode which has an amplitude greater than 30 V but not greater than 200 V and a frequency of 1 MHz to 50 MHz;

• wherein at least the length of the first etching segment during an etching step is determined using a device for detecting an etching base polymer breakdown, and
• wherein an optical emission spectrometer, a laser interferometer, or a reflectometer is used as the device for detecting the etching base polymer breakdown, the device continuously or randomly detecting one of the measured physical quantities characterizing the etching base polymer breakdown.