Tung & Associates
Method for preventing corrosion in load-lock chambers
 A method for preventing corrosion in a load-lock chamber used in a cluster-type wafer processing system by utilizing an additional degas chamber and by the execution of an additional degas operation is provided. In the method, a degas chamber which is equipped with a purge gas inlet and a purge gas outlet directed at a wafer surface positioned in the degas chamber is used. The wafer is degassed by a purge gas of N.sub.2, O.sub.2 or any other suitable gas prior to being transferred back to a load-lock chamber. A suitable purge gas flow rate between about 100 sccm and about 5,000 sccm is used to effectively purge away undesirable, residual process gas from the surface of a wafer. In an alternate embodiment, the purge gas of N.sub.2 or O.sub.2 may be preheated to at least 30.degree. C. to improve the efficiency of purging. In another alternate embodiment, the wafer itself may be heated in the degas chamber to a temperature of between about 100.degree. C. and about 250.degree. C. during the degassing operation such that undesirable residual corrosive gas may be more efficiently removed in a shorter time period. 
Taiwan Semiconductor Manufacturing Company, Ltd.
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additional inventional inventional inventional
Wen Chyi Long Hoang Jia Rong
Wang Peng Chen