SELF-COMPENSATING HYDROSTATIC FLATTENING OF SEMICONDUCTOR SUBSTRATES

摘要

A semiconductive substrate, such as a silicon wafer, is mounted on a baseplate for inclusion in an optical device such as a liquid crystal light valve. An optical flat presses the top surface of silicon wafer toward the baseplate and against an O-ring seal surrounding a fluid adhesive. The fluid adhesive hydrostatically distributes the force of compression to guarantee optical flatness and self-compensation for the amount fluid adhesive surrounded by the O-ring. The optical flatness of the semiconductor substrate is limited only by the flatness of the optical flat against which it is compressed. Parallel alignment of the optical flat, the substrate and the baseplate is achieved by reflecting a laser beam through the semiconductive substrate and observing the interference fringes therein, while adjusting the relative alignment so as to maximize the distance between fringes.