Inventors:
Robert E. Aldridge - Anaheim CA
Russell Elloway - Riverside CA
William O. Fritz - Anaheim CA
Ralph D. Goff - Placentia CA
Michael J. Herrera - Placentia CA
Assignee:
Thermco Systems, Inc. - Orange CA
International Classification:
F27D 118
Abstract:
A soft landing cantilever boat loader for loading semiconductor wafer carrying boats into a furnace process tube includes a loading station having one or more loading assemblies, an automatically controlled door associated with each loading assembly for selectively closing an end of the process tube and a microcomputer based control system for controlling and coordinating process operations. The loading assemblies are of a low profile configuration and each include a boat supporting, cantilevered paddle that is mounted by a quick release mechanism on a carriage which is driven along ways by a motor. A motor speed control circuit provides closed loop motor speed using a pulse width modulated motor drive. A door operating mechanism provides movement of the door along two transverse axes to assure tight sealing of the door against the tube. The control system employs a selfteaching technique that permits rapid reprogramming of the carriage travel limits which may be required when the paddle is replaced by a paddle of a different type or length.