Patent ID: 6183186
Filing Date: 2001-02-06
Classification: H01L,Y10S

Abstract:
In a wafer handling system, a wafer cassette positioner for supporting and shifting wafer cassettes having a plurality of wafer holding slots to successively position the wafer holding slots at a wafer transfer location in a wafer transfer zone, the wafer cassette positioner comprising:a positioner support;first and second spaced apart cassette holders, the first and second cassette holders each being configured to hold at least one wafer cassette with the wafer holding slots of the wafer cassettes being oriented in a first direction;a first elevator supporting the first cassette holder and operable to incrementally index the at least one wafer cassette supported by the first cassette holder in an upright direction to position individual wafer holding slots of the supported cassette at the wafer transfer location when the first cassette holder is in the wafer transfer zone;a second elevator supporting the second cassette holder and operable to incrementally index the at least one wafer cassette supported by the second cassette holder in an upright direction so as to position wafer slots of such wafer cassette supported by the second cassette holder at the wafer transfer location when the second cassette holder is positioned in the wafer transfer zone;at least one elevator mover coupled to the positioner support and operable to shift the first elevator and the first cassette holder from a first position in which the at least one wafer cassette supported by the first cassette holder is in the wafer transfer zone to a second position in which the at least one wafer cassette supported by the first cassette holder is at a second position spaced from the wafer transfer zone, the elevator mover also being operable to shift the second elevator and the second cassette holder from a third position in which the at least one wafer cassette supported by the second cassette holder is spaced from the wafer transfer zone to a fourth position in which the at least one wafer cassette supported by the second cassette holder is in the wafer transfer zone, and wherein the first and fourth positions are at the same location.