Surface grinding machine.

摘要

A surface grinding machine comprises a wheel head (5) vertically movable supported; a cup-shaped diamond wheel (6) supported by a rotatable wheel shaft (7) at one end of the wheel head and having a abrasive grain layer (13) of Young's modulus (10 - 15) x 10<4> kgf/cm<2> at the lower end of the wheel; a wheel shaft driving motor (8) for rotating the cup-shaped diamond wheel supported by the wheel head; a servomotor (10) for vertically moving the wheel head; a suitable number of chuck tables (2) for fixing the surface of a III-V group compound semiconductor wafer (1) on which elements have been fabricated; an index table (3) for rotatably supporting the chuck tables; a chuck table driving motor (4) for turning the chuck tables; a main shaft motor current analysis circuit (30) for detecting the current value of the wheel shaft driving motor; a main shaft rotation number analysis circuit (40) for detecting the number of rotations of the wheel shaft driving motor, and a feed speed control circuit (50) for controlling the servomotor in such a manner as to decrease the feed speed when the grinding resistance is greater than a predetermined resistance value, and increase the feed speed when the grinding resistance is smaller than the predetermined resistance value.