Patent ID: 8058890

Claim:
A test handler, comprising: a first stacker loading a user tray therein, and positioned under a loading plate; a second stacker loading a user tray therein, and positioned under an unloading plate; a third stacker positioned between the first stacker positioned under the loading plate and the second stacker positioned under the unloading plate, with the third stacker loading an empty user tray having no device; a plurality of transfers moving the user tray from the stackers to the loading plate or the unloading plate, or moving the user tray from the loading plate or the unloading plate to the stackers, the transfers being sequentially arranged in a horizontal direction, each of the transfers comprising: a gripper for selectively gripping and un-gripping the user tray; and a vertical movement unit for moving the gripper in a vertical direction; and a plurality of horizontal movement units for moving the transfers in a horizontal direction, respectively, wherein the horizontal movement units are independently operated.