Siltronic Ag

Other

Joachim Junge

Robert Weiss

Georg Pietsch

Anton Huber

J&ouml;rg Moser

A method produces wafers from a cylindrical ingot of semiconductor material having an axis and an indexing notch in an outer surface of the cylindrical ingot and parallel to the axis. The method includes, in the order specified: (a) simultaneous removal of a multiplicity of sliced wafers from the cylindrical ingot by multi-wire slicing in the presence of a cutting agent; (b) etching of the sliced wafers with an alkaline etchant in an etching bath at a temperature of 20° C. to 50° C. and for a residence time, such that the material removed from each of the sliced wafers is less than 5/1000 of an initial wafer thickness; and (c) grinding of the etched wafers by simultaneous double-disk grinding using an annular abrasive covering.

Method for producing discs from a cylindrical rod made of a semiconductor material

Correction of grinding spindle positions in double-side grinding machines for the simultaneous double-side machining of semiconductor wafers is achieved by torsionally coupling the two grinding spindles, each comprising a grinding disk flange for receiving a grinding disk, and providing a measuring unit with an inclinometer and two sensors for distance measurement, between the two grinding disk flanges such that the grinding spindles are essentially in the position they would have with mounted grinding disks during the grinding process, wherein the coupled grinding spindles are rotated while inclinometer and sensors determine radial and axial correction values of axial alignment to adjust the grinding spindles to a symmetrical orientation. The spindle positions may be corrected under the action of process forces.

Simultaneous double-side grinding of semiconductor wafers

Semiconductor wafers are processed so as to remove material on one or both sides by means of at least one grinding tool, with coolant supplied into a contact region between the semiconductor wafer and the at least one grinding tool, characterized in that the coolant flow rate is set as a function of a grinding tooth height of the at least one grinding tool and this coolant flow rate is reduced as the grinding tooth height decreases.

Method for grinding semiconductor wafers

A device for the simultaneous double-side grinding of workpiece wafers has two collinear grinding wheels and two hydropads oppositely positioned for hydrostatic bearing of the workpiece, each having at least one hydrostatic bearing and at least one dynamic pressure tube for measuring the spacing between the workpiece and the hydrdopads. The surfaces of the hydropads which face the workpiece are of nonplanar configuration, contoured in such a manner that the spacing between the surface and the workpiece adopts a minimum value near the edge of the hydropads proximate the grinding wheels, this spacing increasing at increasing distance from the grinding wheels. In a further embodiment, at least one bore, through which liquid and abraded material can be discharged from the vicinity of the dynamic pressure tube, is proximate each dynamic pressure tube.

Device for the simultaneous double-side grinding of a workpiece in wafer form

A method for cutting a multiplicity of disks from a hard brittle workpiece is by moving the workpiece at a defined feed rate through a wire web of a wire saw. In the method, the wire web is formed by a sawing wire which moves in a reciprocating manner and is covered with bonded abrasive grain. A cooling liquid is provided beneath the wire web, in which cooling liquid the sawing wire of the wire web is immersed when cutting off the disks. Also provided is a wire saw which is suitable for carrying out the method.

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Burghausen, Germany

Joachim Junge