COAXIAL SHAFTS FOR RADIAL POSITIONING OF ROTATING MAGNETRON

摘要

A magnetron actuator (140) for moving a magnetron (42) in a nearly arbitrary radial and azimuthal path in the back of a target (18) in a plasma sputter chamber (10). The magnetron actuator includes two coaxial rotary shafts (28, 30) extending along the chamber central axis (14) and coupled to two independently controllable rotary actuators (178, 18). An epicyclic gear mechanism (40) or a frog-leg structure (210) mechanically couple the shafts to the magnetron to control its radial and azimuthal position. A vertical actuator (144) moves the shafts vertically in tandem to vary the magnetron's separation from the target's back surface and compensate for erosion of the front surface. The rotary actuators may be separately coupled to the shafts or a rotatable ring gear may be coupled to the shafts through respectively fixed and orbiting idler gears. Two radially spaced sensors (234, 236) detect reflectors (230, 232) attached to the inner and outer arms (116, 122) of the epicyclic gear mechanism for homing of the controller (238).