Patent ID: 6137303
Filing Date: 2000-10-24
Classification: G01R

Abstract:
An apparatus for testing and inspecting semiconductor wafers having a plurality of devices at least partially formed thereon comprising:at least one cassette station for the unloading of wafers from a cassette and the loading of wafers onto a cassette;a plurality of wafer inspection or test stations disposed around a vertical axis;each inspection station having thereat an inspection head moveable in a horizontal plane to a position adjacent a selected device on a horizontally disposed wafer located at the inspection station;a transfer mechanism operable to transport wafers between the at least one cassette station and the inspection stations, the transfer mechanism including a carousel that includes a horizontal table that is rotatable about said vertical axis and has a plurality of wafer holders at fixed locations thereon spaced radially from and angularly around the axis such that, when the table is angularly indexed around the axis, different ones of the wafer holders simultaneously move individual wafers sequentially to positions at different ones of the stations, the transfer mechanism further including a robot arm operable to move a wafer non-sequentially between any of a plurality of the holders on the table and any of a plurality of other holders on the table or a cassette; andat least one wafer elevator operable to raise a wafer, transported to a test or inspection station by the transfer mechanism, from a wafer holder vertically upward into a test or inspection position adjacent a test or inspection head at one of the test or inspection stations and for lowering the wafer vertically from the test or inspection position.