The disclosure is directed to a method and apparatus for superfinishing magnetic disk substrates using a non-friable polishing pad including a high density polyurethane foam binder in which at least 50 percent by weight of classified hard particles are retained. Polishing occurs by rotating the pad against the surface to be ultrafinished in the presence of a water soluable liquid vehicle maintaining a minimum pressure of 5 pounds per square inch at a rotational speed that achieves the desired aggressiveness of the polishing media. The method and apparatus contemplate both the ultrafinishing of newly prepared substrate disks and the restoring of previously coated disks to a ultrafinished substrate condition without producing substances or conditions toxic to the ecology or the operator.
A double side grinding apparatus for thin disklike work comprises a pair of rotatable grinding wheels having opposed circular grinding faces provided by respective end faces and so arranged as to be movable relative to each other axially thereof, and work rotating means for rotating the thin disklike work about its own axis while supporting the work in a grinding position between the grinding faces so that opposite surfaces of the work to be worked on face the respective grinding faces of the pair of the wheels, with an outer periphery of the work intersecting an outer periphery of each grinding face and with the center of the work positioned inwardly of the grinding faces.
A pair of ring-shaped lapping plates 13, 23 are faced to both surfaces of a wafer 1. Each lapping plate 13, 23 has an outer diameter approximately equal to a radius of the wafer 1 and a lapping surface 14, 24 sliding in contact with the wafer 1. Each lapping plate 13, 23 is rotated along a direction reverse from the other, while an abrasion slurry A is fed into cavities 15, 25 of the lapping plates 13, 23 and discharged together with dusts separated from the wafer 1 through grooves engraved in the lapping surfaces 14, 24 and gaps between the wafer 1 and the lapping surfaces 14, 24. The lapping plate 23 is carried toward the stationary lapping plate 13 at a rate corresponding to abrasion of the lapping surfaces 14, 24. During lapping, the wafer 1 is rotated by drive rollers 31 and supported by guide rollers 32. In this way, both surfaces of the wafer 1 are simultaneously lapped.
A pair of ring-shaped lapping plates 13, 23 are faced to both surfaces of a wafer 1. Each lapping plate 13, 23 has an outer diameter approximately equal to a radius of the wafer 1 and a lapping surface 14, 24 sliding in contact with the wafer 1. Each lapping plate 13, 23 is rotated along a direction reverse from the other, while an abrasion slurry A is fed into cavities 15, 25 of the lapping plates 13, 23 and discharged together with dusts separated from the wafer 1 through grooves engraved in the lapping surfaces 14, 24 and gaps between the wafer 1 and the lapping surfaces 14, 24. The lapping plate 23 is carried toward the stationary lapping plate 13 at a rate corresponding to abrasion of the lapping surfaces 14, 24. During lapping, the wafer 1 is rotated by drive rollers 31 and supported by guide rollers 32. In this way, both surfaces of the wafer 1 are simultaneously lapped.
A process for machining a wafer-like workpiece between two plates, in which material is abraded from the workpiece under the influence of an auxiliary substance supplied and of a pressure acting on the workpiece. In this process, the pressure on the workpiece is significantly reduced and then increased again at least once during the machining of the workpiece, and the supply of the auxiliary substance is reduced as the pressure is increased.
The method of finishing the surface of a disc, such as a disc whereon information is magnetically recorded for use in computers and the like. It involves urging against one side of a rotating disc, a polishing pad having a polishing compound or medium thereon, and simultaneously urging a non-polishing pad against the opposite side of such disc in alignment with the polishing pad. To simultaneously polish the opposite side surfaces of the disc, a second pair of pads (one polishing and one non-polishing) is equiangularly spaced on the disc in relation to the first pair of pads, but the pads of the second pair of pads are reversed so as to cause the finishing process to occur on the disc side not being polished by the first pair of pads. Any desired even numbered pairs of pads may be employed. The polishing and non-polishing pads are caused to rotate relative to and against the respective side of the disc as the disc itself is caused to rotate about its axis.
