Abstract: A method for producing optically flat thin semiconductor wafers (12) bonded to a substrate (16). The wafer (12) is bonded without touching the top surface of the wafer (12). Also, the bond is created without the use of pressure. Electrostatic bonding, or contact bonding or both may be employed. After the wafer (12) is bonded, it is then polished to a desired thickness and flatness. After contact bonding and polishing the wafer (12) may then be removed for further processing. The wafer may then be contact bonded to a final substrate (b 34) or electrostatically bonded to a final substrate (42). The contact bonding technique may also be employed as a means for holding the wafer (12) during precise photolithography. The optical flatness achieved permits improved yields over conventional means for securing wafers during photolithography. The electrostatic bonding technique permits extremely thin optically flat silicon wafers to be produced.

Abstract: A liquid crystal light valve is provided with a microgrid of grooves in the photoconductor surface to divide the photoconductor into high resolution pixels. The liquid crystals fill the grooves to seal them and contribute to a potential barrier at the grooves that prevents lateral charge migration between pixels. In a metal oxide semiconductor (MOS) embodiment an oxide layer extends over the pixels and partially overhangs the grooves. A metal matrix mirror is formed over the insulative layer, and extends into a portion of the grooves to shield the underlying silicon from photoactivation while maintaining an electrical isolation between pixels.

Abstract: An apparatus is provided for fabricating a semiconductor device by thermal gradient zone melting, whereby metal-rich droplets such as aluminum migrate through a semiconductor wafer such as silicon to create conductive paths. One surface of the wafer is placed directly on a heating surface to establish a high and uniform thermal gradient through the wafer. Heat in the wafer is removed from the other wafer surface. The apparatus for fabricating semiconductor devices utilizing temperature gradient zone melting comprises a base, heating means and heat sink means. Heating means comprises a platform having a generally planar heating surface adapted to receive the entire area of the one surface of at least one wafer. The heat sink means is spaced away from the other wafer surface to form a space therebetween, the space being adapted to receive a high heat conductive gas. The heat sink means and the gas cooperatively remove the heat in the wafer to enhance the establishment of the thermal gradient.