Verfahren zur Herstellung von Markierungen zum Alignieren von Marken.

摘要

Process for making alignment marks for masks on an active face of a semiconductor substrate (12) according to which a layer (13) of a material resistant to oxidation is firstly formed, and then zones (15') for insulation by a field oxide are defined through localised etching, at the same time as the alignment marks (17'). According to the invention, after the localised etching of the layer (13) of anti-oxidation material, and whilst making use of the remaining portions of this layer as a selective mask, depressions (26) of specified depth are produced at the surface of the substrate, at least in windows (18) which contain the alignment marks, the surface of the substrate is next laid bare inside the said windows, and finally a thermal oxidation step is performed in order to produce the field oxide (19') and in the course of which the alignment marks (18) are simultaneously covered with oxide (24).