CONTROL OF ARBITRARY SCAN PATH OF A ROTATING MAGNETRON

摘要

A control system and method for controlling two motors (32, 36) determining the azimuthal and circumferential position of a magnetron (42) rotating about the central axis (14) of the sputter chamber (10) in back of its sputtering target (18) and capable of a nearly arbitrary scan path, e.g., with a planetary gear mechanism. A system controller (88) periodically sends commands to the motion controller (150) which closely controls the motors. Each command includes a command ticket, which may be one of several values. The motion controller accepts only commands having a command ticket of a different value from the immediately preceding command. One command selects a scan profile stored in the motion controller, which calculates motor signals from the selected profile. Another command instructs a dynamic homing command which interrogates sensors (166, 174) to determine if the arms (190, 192) are in the expected positions or need to be rehomed.