Magnetically supported grinding shaft for machining microelectronic waters

摘要

The grinding shaft is fully magnetically supported for achieving the inclination of the grinding disc required for clamping the wafer on a conical chuck to obtain a surface-parallel machining.The grinding shaft is so inclined that by the magnetic bearings the shaft centre points do not coincide with the geometrical centre points of the magnetic bearings. The shifting of the shaft centre points wrt. the bearing centre points is carried out by presetting electric rated value signals to the bearing control, corresp. to the new rated positions.