Method and apparatus for alignment of submicron lithographic features

摘要

In the manufacture of microelectronic and optoelectronic circuitry, an arrangement for aligning submicrometer lithographic features on a wafer illuminating a diffraction grating on the wafer with an interferometrically established radiation intensity pattern having a predetermined relationship to the lithographic features in another level of the wafer that is to be exposed, the radiation diffracted from the illuminated grating forming moire interference pattern providing spatial amplification of the grating period for alignment purposes by the ratio of the moire fringe spacing to the grating period.