Characterization of mask alignment offsets using null wire segment holograms and a progressive offset technique

This paper presents data characterizing alignment offsets in a commercial 1 /spl mu/m fabrication process using a combination of null wire segment holograms and a progressive offset technique. The test structure is essentially a binary computer generated hologram constructed from wire segments and is designed to project a null image when the masks for the process are in prefect alignment. Characterization using the technique indicates a mask misalignment of between 0.1 and 0.3 /spl mu/m, and this is confirmed using atomic force microscopy.