Abstract: First and second plates are formed with like periodic patterns. A laser beam illuminates the second plate through the alignment marks of the first plate to provide a pair of diffracted beams that are detected with alignment being indicated when the beams are of the same intensity.

Abstract: A new technique for fabricating high contrast X-ray masks with precisely controlled linewidths of less than 100 A is described. The technique is based on the deposition at an oblique angle ("shadowing") of X-ray absorber material onto relief structures of triangular or square cross-section in a polyimide plastic membrane. Precise linewidth control is possible because shadowing angle, absorber thickness and relief structure can be precisely determined. The smooth and well-controlled triangular cross-section structures required are produced in silicon by anisotropic chemical etching and then transferred to polyimide by molding. The square structures are made by reactive-ion-etching SiO.sub.2 with CHF.sub.3 and are transferred to polyimide by molding. Results of a numerical model of carbon K (45 A) X-ray exposures in PMMA of shadowed triangular profile masks are presented which indicate that linewidth control of .+-.50 A should be possible for submicrometer period gratings.

Abstract: Ordered liquids, or mesophases, are aligned by forming a structure on a substrate surface using a planar process of formation, the surface structure having a predetermined pattern, and applying a mesophase to the surface to substantially orient the molecules of the mesophase in accordance with the predetermined pattern. A liquid crystal display device can be made in which, in a preferred embodiment, the liquid crystal is confined between two substrates having oppositely disposed surfaces on which selected patterns of surface structures have been formed. The surface structures can be grating structures made of a conductive material, such as metal, which structures act to align the liquid crystal in accordance with the selected patterns, to polarize light passing through the surface structures, and to provide electrical contacts so that an electrical signal applied thereto can produce an electric field in the region between the substrate surface structures.

Abstract: A process for fabricating polyimide membrane x-ray lithography masks is described. Thin membrane of polyimide is formed by spinning polyamic acid on a glass substrate and polymerizing in situ. The glass substrate acts as a holder and efficient heat sink during formation of gold absorber patterns on top of the polyimide. A support ring is then bonded to the polyimide, and the glass etched in dilute HF. Optically smooth polyimide membranes with thickness from 0.5 to 5 .mu.m are readily achieved. The method and resulting product is not limited to the above materials or to masks.

Abstract: First and second plates are formed with like periodic patterns. A laser beam illuminates the second plate through the alignment marks of the first plate to provide a pair of diffracted beams that are detected with alignment being indicated when the beams are of the same intensity.

Abstract: A process for fabricating polyimide membrane x-ray lithography masks is described. Thin membrane of polyimide is formed by spinning polyamic acid on a glass substrate and polymerizing in situ. The glass substrate acts as a holder and efficient heat sink during formation of gold absorber patterns on top of the polyimide. A support ring is then bonded to the polyimide, and the glass etched in dilute HF. Optically smooth polyimide membranes with thicknesses from 0.5 to 5 .mu.m are readily achieved. The method and resulting product is not limited to the above materials or to masks.