Patent ID: 7438514

Claim:
A wafer transfer system, comprising: a loadport for receiving a wafer container; a housing operably connected to the loadport; a wafer transfer mechanism for transferring a wafer between the wafer container and the housing; a wafer container sensor for detecting a presence of the wafer container on the loadport; a variable speed fan disposed in a first portion of the housing; a variable exhaust unit disposed in a second portion of the housing facing the first portion, the variable exhaust unit being capable of varying an exhaust rate of air from the housing; and a controller configured to variably operate the variable speed fan and the variable exhaust unit in response to a signal from the wafer container sensor, wherein the variable exhaust unit comprises: a first exhaust plate including a plurality of first openings; a second exhaust plate including a plurality of second openings; and a third exhaust plate including a plurality of third openings, the second exhaust plate being positioned between the first and third exhaust plates, the second plate being operable to move relative to the first and third plates, thereby aligning or misaligning the plurality of first through third openings.