Robot pre-positioning in a wafer processing system

(-- 57) summary -- the wafer cluster tool which operates regularly and periodically is described. The enforcement form of the present invention has the periodicity of 1 delivery cycle. The present invention enables judgment of pickup time to the processing chamber of a cluster tool, and the enforcement form of the present invention enables the creation and maintenance of a schedule which were updated. A schedule shows time for each of a processing chamber to receive a robot's service. These values are updated when a processing chamber receives a new wafer. The robot in a cluster tool may arrange these selves beforehand before the module which should serve, or a processing chamber. The waiting time of each module exceeding the queue time beforehand determined to the module by prior arrangement of a robot is eliminated. Thereby, in a front, each robot's course becomes deterministic, and a cluster tool is enabled to use the robot of a single gripper.