Photolithography

Transfer of a geometrical structure to a substrate by means of a mask consisting of photoresist. besteht. The photoresist, either positive photoresist or negative photoresist, is applied over the entire surface of the substrate to be etched, followed by exposure together with the geometrical structure to be created on it. Next, developer is applied to dissolve the photoresist in the exposed (positive photoresist) or non-exposed (negative photoresist) areas and thus to strip the substrate layer there. If the entire surface is treated, for example by reactive ion etching (RIE), only the exposed areas of the substrate are changed.