Abstract: Master discs and similar devices used in the production of digital data storage and recording discs and the like are produced with a substrate member which is provided with a layer of material which is applied to the substrate member in liquid form of a thickness greater than the surface roughness of the substrate member and of a thickness greater than any particulates present on the substrate member. The material layer is preferably a polymer such as epoxy, acrylic or styrene and is hardenable by exposure to UV light, heat, air circulation or catalytic reaction to provide a substantially smooth flat surface for receiving a data bearing film. The film may be treated to generate bumps or pits representing digital signals, for example, which are free of any defects resulting from surface roughness or contamination of the substrate member.

Abstract: An apparatus for grinding the edges of planar workpieces such as semiconductor wafers, wherein an abrasive material is provided on the side of a flexible substrate which is mounted in a cantilevered fashion. By virtue of the flexibility in the substrate, the grinding surface can move in and out, if necessary, in order to accommodate any eccentricities or out-of-round portions of the planar workpiece. In a preferred embodiment for semiconductor wafer processing, the wafer is rotated at a speed in excess of 3000 rpm and as high as, say, 10,000 rpm. The grinding surface is preferably established on a round disc which is centrally supported on a shaft; and loading on the grinding surface is typically in a direction that is generally parallel to the longitudinal axis of the shaft.

Abstract: In the manufacture of semiconductor components thin films of submicron thickness are in widespread use. To produce the submicron thick films free of entrapped pockets of air, a platform, to which a substrate surface is mounted, is initially caused to oscillate in a shaking motion to produce a shearing force to lift minute pockets of air trapped at the liquid-substrate interface to permit migration to the surface of the liquid where they escape. This initial oscillating operation is provided by a permanent magnet A-C motor driven as a synchronous motor by the output of a frequency generator. The motor control circuit, including the frequency generator, energizes the A-C motor to initially cause the oscillating motion of the platform (chuck) carrying the substrate surface. After the initial time period of oscillating motion, the control circuit provides a high frequency signal to the motor for high speed rotation in one direction to produce a drying action to the thin, film-forming liquid.

Abstract: A construction for an electric motor, which motor is adapted to be installed and operated in a generally vertical mode. The rotor shaft of the motor extends upward through the top wall (or cap) of the stator housing. With this vertical orientation, however, there exists the possibility of unwanted liquids flowing downward alongside the rotor shaft into the housing where they could cause damage to the motor windings, etc. To protect sensitive interior parts of the motor, an annular trough is interiorly provided for capturing such liquids as may enter the housing by flowing downward along the rotor shaft. A shield or skirt is sealingly attached to the rotor shaft within the housing at a position where the shield extends radially outward over the trough. Drainage passages connect the trough to the exterior of the housing, such that unwanted liquids will be initially captured and then drained from the housing before they can reach an interior location where they could cause damage.