The invention relates to the technical field of semiconductors, in particular to a photoetching
overlay mark and a preparation method thereof. The preparation method comprises the following steps of S1, manufacturing a mark point pattern, transferring the mark point pattern to a
chip, and exposing an epitaxial layer; s2,
etching the epitaxial layer; s3, evaporating a
metal mark point, wherein themetal structure is CrAlTiPtAu, and the CrAlTiPtAu
metal structure sequentially comprises a
metal Cr layer, an Al layer, a Ti layer, a Pt layer and an Au layer from bottom to top. and S4, stripping anddegumming. The photoetching
overlay mark prepared by the method provided by the invention has strong
wear resistance and
high resolution, is not easy to corrode, and is slightly influenced by the physical bombardment of ions and the
corrosion of a
chemical solution; and meanwhile, metal marking points can reflect light rays, so that the metal marking points are clearer, and the alignment accuracyis improved.