Unova UK Limited

Mark Andrew Stocker

Dermot Robert Falkner

Michael George Pierse

Paul Martin Howard Morantz

Matthew James Ball

Peter Vaughan Mawer

Paul Martin Morantz

A method of positioning a grooved grinding wheel relative to a disc-like circular workpiece for edge grinding the workpiece using the groove in the wheel includes the steps of mounting the workpiece for rotation about a first axis, mounting the grinding wheel for rotation about a second parallel axis, effecting relative movement between the workpiece and the wheel to engage the rim of the wheel within the groove and performing a preliminary grind. The position of the wheel is axially adjusted in accordance with the measurements made on the profile of the rim produced by the preliminary grind, and the rim is ground again with a second preliminary grind with the grinding wheel located at the axially shifted position. The steps of grinding and measuring the periphery of the workpiece are repeated until the rim profile possesses the desired accuracy. The final position of the grooved grinding wheel is then utilized for grinding future wafers.

Edge grinding

A grinding pin ( ) for grinding notches in the edges of disc workpieces, such as semi-conductor wafers, comprises a metal spindle ( ) for mounting in a grinding machine, and an adjoining cylindrical region having axially spaced sections of fine grit ( ) and rough grit ( ), the latter being axially nearer the spindle ( ). In use on a grinding machine having a rotatable forming wheel, similar profiled notch-grinding grooves ( ) and ( ) are formed by the wheel in the grinding sections ( ) and ( ) respectively.

Grinding pin for grinding machines comprising resin bonded selections of rough grit and fine grit

A method of grinding the edge of a disc uses a grinding machine having mounted thereon a grooved grinding wheel, in which the groove is formed in situ using a forming wheel also mounted on the grinding machine. After a workpiece has been ground or after a succession of workpieces have been ground, re-engaging the grinding wheel and the forming wheel with the grinding wheel remaining in situ, to re-form the groove in the grinding wheel to correct for wear. A grinding machine comprises a grinding wheel, drive means therefor, a workhead and workpiece spindle and drive means therefor, a forming wheel and drive means therefor, means for moving the grinding wheel so as to plunge grind the edge of the grinding wheel to form a groove therein of precise cross-section and means for effecting relative movement between the grinding wheel and the forming wheel to enable the grinding wheel to engage with the edge of a circular workpiece component mounted on the workpiece spindle to edge grind the component and wherein the forming wheel is also mounted on the workpiece spindle for rotation therewith, and the grinding wheel is a resin bonded wheel.

Grinding and polishing machines

A semi-conductor wafer ( ) has its inclined edge flanks polished by a grooved wheel ( ) of synthetic plastics material, while a jet ( ) of polishing slurry, which may comprise colloidal silica, is fed downwards into the zone of contact between the wheel and the wafer. The wheel ( ) is preferably rocked or oscillated laterally such that a constant polishing force is alternatively applied to each flank of the wafer ( ). The wheel may be mounted in a buffer store to which the wafers are transported from a grinding station which grinds the edge flanks.

Wafer edge polishing method and apparatus

Grinding machines and polishing machines

A workpiece alignment and shifting system for moving circular workpieces from a first inspection station to a second machining station, comprises workpiece holding means for attachment to the face of a disc workpiece to move the latter from one position to another. Robotic means controls the position of the workpiece holding means and is adapted to move in a least two orthogonal directions, both of which are parallel to the plane of the disc when it occupies the first station. The disc is rotated in the inspection station and in the machining station and inspection means determines the position of the geometric center of the disc as it is rotated. Computing means calculates from data delivered by the inspection means the two shifts required along the orthogonal directions of movement of the robotic means, to move the geometric center of the disc to a second desired position whose coordinates are known. The computing means includes memory means for storing the said coordinates. The coordinates are those of the center of rotation of the workpiece holder or chuck in the said second station. The workpiece holding means is vacuum operated. A three axis robot is employed to pick and place disc-like wafers of semi-conductor material for edge grinding, and movement along two of the robot axes, X and Z, is used to control the centering of the wafer on a vacuum chuck in the second grinding station.

Workpiece inspection and handling

A grinding pin (,) for notch grinding is provided. The grinding pin comprises a cylindrical region of formable grinding material and in which is formed a groove (,) for forming a notch. The length of the cylindrical region is such that further grooves (,) can be formed therein as each groove becomes too worn to form a notch.

Grinding machines

A grinding or polishing machine comprises a rigid platform on which a workhead spindle and a grinding wheel spindle are located. The grinding wheel spindle is mounted on a sub-assembly which is attached to the platform by means of flexures which permit limited movement of the sub-assembly in a direction generally parallel to the direction in which the wheel has to advance to achieve grinding or polishing of a workpiece mounted on the workhead spindle. The flexures generally inhibit movement of the sub-assembly in all other directions. Two grinding wheels are mounted on the platform, one on each of two sub-assemblies, and each sub-assembly is attached to the platform by flexures as aforesaid. The flexure mounting points are located generally centrally of the machine and are located on either side of and close to the machine centre line. In a grinding or polishing machine having workpiece spindle means, tool spindle means mounted on sub-assemblies which permit limited relative movement in one direction to effect tool and workpiece engagement cam drive means is provided whereby each sub-assembly is movable to advance or retract each tool spindle towards and away from the workhead spindle.

Grinding machine spindle flexibly attached to platform

A grinding machine for grinding the edge of a disc or wafer comprises a grooved grinding wheel 308, means for transporting the wafers before or after grinding, and a housing 332 in which wafers 340 are parked on a vacuum chuck 336 awaiting inspection. A jet 338 protrudes into the housing and directs water or air towards the face and edge of the wafer on the chuck. The transport means then transfers wafers to an inspection station.

Growing community of inventors

East Hunsbury, United Kingdom

Mark Andrew Stocker