Patent ID: 7115513
Filing Date: 2006-10-03
Classification: G02F,Y10S

Abstract:
1. A domain reversal alignment method for forming photolithographic mask alignment keys on surfaces of a unidirectionally polarized ferroelectric material comprising: providing a substrate which is a unidirectionally polarized ferroelectric material having opposing first and second planar surfaces which are substantially parallel and wherein said polarization is directed substantially towards said first surface from said second surface; forming a layer of photosensitive material on the first surface of said substrate; patterning said photosensitive layer to produce openings having an alignment key shape, said openings exposing corresponding surface regions of said substrate surface; hardening said photosensitive layer by thermal processing and rendering said layer, thereby, an insulator; coating said surface regions with a conducting liquid; producing an electric field in a region within the substrate interior between said exposed substrate first surface regions and second substrate surface, said electric field reversing the unidirectional polarization within said interior region; and then removing said photosensitive layer; and etching substrate first and second surfaces to produce, thereby, surface indentations having said alignment key shape on both the first and second substrate surfaces, the indentation on the first surface being vertically aligned with a corresponding indentation on the second surface and said surface indentations forming alignment keys for the subsequent alignment of photolithographic masks over said surfaces.