VERFAHREN ZUM DUENNAETZEN VON SUBSTRATEN

In a process for the chemical thinning of etching substrates by means of chemical etchant, a predetermined thickness of a monocrystalline substrate with an undisturbed grating structure is retained by irradiating the substrate during the etching process by a radiation source with a beam impinging perpendicularly to the substrate surface, the substrate consisting of a material capable of absorbing the radiation, the wavelength of the main part of the beam being selected such that the absorption length of radiation in this wavelength in the substrate material is greater than the desired substrate thickness.