| 摘要 |
A high speed wafer processing apparatus employs two wafer transport robots to move wafers from two load locks past a processing station with gentle vacuum cycling and without pumpdown delays. Both robots alternately transport each wafer from the cassette at a single one of the load locks along a path from the cassette to a transfer position through the process station and back to the cassette, while pumpdown or venting of the other (second) load lock is carried out. They then transport the wafers from the second load lock through the process station. A wafer is "parked" at a transfer or orienting station, rather than handed over from robot to robot, so that the robots are not both tied up with a single wafer, and two or more wafers can move simultaneously along the path. Even for a fast ten second process time, work flow proceeds without interruption, periodic delay or dead time, and three to five minutes are available for venting, loading a new cassette and pumpdown. The robots enjoy partial path overlap, and operate in bucket brigade fashion without stop. <MATH> |
