Patent ID: 8303231

Claim:
An apparatus for semiconductor wafer transfer, comprising: a first region for placement of at least one pod having a cassette, wherein the cassette carries wafers; a second region for placement of a corresponding cassette; a first stage; a second stage coupled to the first stage; a carrying mechanism coupled to the first stage configured to move the second stage in the horizontal direction toward the first stage; a third stage coupled to the second stage, wherein the carrying mechanism has a first screw drive to coarsely move the third stage together with the second stage in the horizontal direction, and a second screw drive to finely move the second stage in the horizontal direction independently and relatively to the third stage; an unloading mechanism coupled to the first stage configured to unload the pod; a push bar coupled to the first stage configured to abut against at least one wafer in a horizontal direction in the unloaded pod to transfer the at least one wafer to the corresponding cassette; wherein the cassette in the first region and the corresponding cassette in the second region are on the same horizontal plane; and wherein the first region is disposed on the first stage and the second region is disposed on the second stage, and wherein the second stage is movable in the horizontal direction so as to provide a distance away from the first stage to allow the unloading mechanism to unload a housing of the pod in a vertical direction when the cassette is on the first stage, and when the corresponding cassette is on the second stage concurrently.