GB1258514A - - Google Patents

Abstract

1,258,514. Grinding. INTERNATIONAL BUSINESS MACHINES CORP. 20 Feb., 1969 [22 March, 1968], No. 9128/69. Heading B3D. Apparatus for finishing a surface of a workpiece 12, Fig. 3, e.g. a silicon wafer, comprises a receiver 60 for maintaining the surface to be finished against a plane finishing surface 11, rotatable drive means for causing the receiver and workpiece cyclically to describe a closed path over the surface 11, and means for simultaneously causing additional relative rectilinear movement between the receiver and the surface 11. The drive means is displaceable along its axis of rotation and is connected to the receiver by a joint 62 which is adapted to communicate axial displacement while permitting the receiver to assume an angular position relative to the axis determined by the position adopted by a workpiece received thereby, as pressure is applied by displacement of the drive means towards the surface 11. As described, workpieces 12 are held in apertures 69 of a floating ring 68 by spring-loaded discs 66 adjustably mounted on a housing ring 61. The ring 61 is eccentrically mounted by the ball joint 62 on a rotatable mount 43 supported for rotational and limited axial movement within a carrier 40. The ring 61 is so supported by springs 73 secured to pads 72 fixed to the carrier 40 that as the mount 43 is rotated the workpieces are moved in closed paths relative to the carrier. Alternatively, the movement of the ring is controlled by a link which is fixed thereto and has a pin-and-slot connection with a fixed part of the carrier. The weight of the mount 43 urges the workpieces against the surface 11 until a pin 48 engages the top edge 50A of a slot therein when the workpieces reach the desired size. A plurality of carriers 40, Fig. 1, is provided and each is moved rectilinearly along the surface 11 by rotation of a threaded rod 78, the carriers being guided by guides 77. The mounts 43 may be rotated by a double-V-belt 47, or each carrier 40 may include its own drive motor, the speed of which may be varied. A plurality of finishing surfaces may be provided which may be separated by cleaning surfaces. The finishing surfaces may be impregnated with diamond dust or an abrasive, lapping, or polishing slurry may be supplied thereto either by spraying or via openings 80 in the surface 11. The slurry may comprise water or oil together with silicon carbide, boron or nitride particles, or silicon oxide or cupric acid. The finishing surfaces may be parts of movable belts which may be shifted when a fresh finishing surface is required. When the finishing operation is completed, a flange 70 on the ring 68, Fig. 3, engages rails 91 which cause it to be raised so that the workpieces can be removed from the discs 66 by a knife.