Siltronic Ag

Ludwig Koester

Peter Storck

Michael Boy

Peter Czurratis

Elena Soyka

Klaus Kraemer

Suitability of silicon wafers for use in device processing without generation of fatal defects is assessed by using SIRD to measure stress in a wafer cut from a piece of a crystal ingot after first and second thermal treatments of the water, the second thermal treatment consisting of a heating phase, a holding phase, and a cooling phase. The result is used to consider whether silicon wafers cut from the piece can adequately survive device processing without generating excess defects.

Method for producing semiconductor wafers

A method for detection of mechanical defects in a semiconductor ingot section which has at least one planar surface, and a thickness at right angles to this surface of 1 cm to 100 cm, involves scanning the planar surface by at least one ultrasound head which is coupled via a liquid coupling medium to the planar surface and, at each measurement point (x,y) producing at least one ultrasound pulse which is directed at the planar surface of the ingot section, recording the ultrasound-pulse echo as a function of time, such that an echo from the planar surface, an echo from a surface opposite the planar surface, and further echoes are detected, with the positions (x, y, z) of mechanical defects in the ingot section being determined from the further echoes.

Growing community of inventors

Burghausen, Germany

Ludwig Koester