Abstract: A method for monitoring the calibration of and calibrating rotating tools ich are liable to deviate, wherein at least one known deviation is recorded at a first predetermined rotational speed. The method can be used with annular saws that divide workpieces into semiconductor wafers.

Abstract: A method for producing semiconductor wafers is by a repeated sequence of grinding the end face of a monocrystal using a grinding tool and cutting a semiconductor wafer having a thickness from the monocrystal using a cutting tool, a grinding abrasion of a specified depth being produced during grinding and the semiconductor wafer being cut in a cutting plane which is as parallel as possible to the ground end face.

Abstract: A method and an apparatus are for machining semiconductor material with a inding tool while feeding a liquid cleaning agent to the working surface of the grinding tool, has the cleaning agent being exposed to sound waves having a specific frequency and having a specific intensity. In one embodiment of the method, the cleaning agent is exposed to sound waves in at least one nozzle and then the cleaning agent is directed against the working surface of the grinding tool. In another embodiment, the cleaning agent is guided through at least two cleaning agent jets against the working surface of the grinding tool, which cleaning agent jets differ from each other in that they are exposed to sound waves of different frequencies.

Abstract: In the annular sawing of bars, in particular of semiconductor material, the ccurate fitting of the saw blade is of great importance. In the case of the conventional clamping systems, in which the saw blade is held on the machine rotary part by clamping forces exerted by means of a holding ring and is subjected to tension by means of an additional clamping ring, inadequate tensioning constancy is usually caused by the tensioning forces acting against the clamping forces. A tensioning behavior which is better in comparison can be achieved according to the invention by the tensioning forces being applied to the clamping ring by clamping elements releasably connected to the machine rotary part and consequently clamping forces and tensioning forces no longer being directed against one another. By the use of such clamping systems, longer saw blade service lives and higher sawing outputs can be achieved.

Abstract: The invention is a method and apparatus for sawing bar-shaped workpieces o slices by means of an annular saw. The saw blade deviation, from its nominal position in the axial direction during the sawing operation, is compensated for. According to the invention, the deviation can be compensated for by the workpiece and the clamping system of the saw blade performing an appropriate relative translatory axial movement in accordance with the measured deviation. This movement is conveniently controlled by a computer, which compares the actual and nominal position of the saw blade with one another. The method can be used especially in the sawing of semiconductor bars.