Method for treating an effluent gas during semiconductor processing

#The present invention relates to the field of semiconductor processing, and, more particularly, to a system and associated method for treating an effluent gas from a semiconductor processing chamber.

#Semiconductor processing operations typically include a chemical vapor deposition (CVD) step for depositing dielectric layers on a semiconductor wafer. The CVD process is performed in a semiconductor processing chamber. A dielectric layer typically includes silicon dioxide, which may be undoped or doped. A common approach for depositing silicon dioxide is to use a tetraethyl orthosilicate (TEOS) reagent. The TEOS reagent may also be subjected to ozone during the CVD process. As a result, the effluent gas released from the semiconductor processing chamber includes unconsumed process gases, as well as by-products of such gases. In particular, the effluent gas contains processed carbon monoxide and unreacted ozone. It is undesirable to release either of these gases into the atmosphere.

#As a result of the above described CVD process, silicon dioxide is also deposited on the walls of the semiconductor processing chamber. Consequently, the walls must be periodically cleaned. A reactive ion etching (RIE) cleaning process may be performed in the semiconductor processing chamber for this purpose. Typically, fluorocarbons are used in the RIE cleaning process to remove silicon dioxide from the chamber walls. The reaction between the fluorocarbons and the deposited silicon dioxide results in the formation of carbon monoxide. The effluent gas released from the semiconductor processing chamber during the RIE cleaning process thus contains carbon monoxide.

#FIG. 1 is a schematic diagram of a semiconductor wafer processing system including a catalytic converter in accordance with the present invention.

#FIGS. 2a-2c are schematic diagrams illustrating different embodiments of the catalyst body carried by the catalytic converter illustrated in FIG. 1.

#FIG. 3 is a flowchart illustrating a method for treating an effluent gas in accordance with the present invention.

#The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

#A semiconductor processing system 20 and associated method for treating an effluent gas released therefrom will be described with reference to FIGS. 1-3 in accordance with the present invention. A semiconductor wafer 24 may be processed via the semiconductor processing system, 20. As will be explained in greater below, the process-performed on the semiconductor wafer 24 may be a chemical vapor deposition (CVD) process for depositing a dielectric layer thereon. The dielectric layer preferably includes silicon dioxide, which may be doped or undoped.

#The semiconductor processing system 20 comprises a processing chamber 26 having an exhaust outlet 28 for releasing an effluent gas 22, and a catalytic converter 30 connected in fluid communication with the exhaust outlet. The catalytic converter 30 comprises at least one mixed metal oxide for catalytically treating the effluent gas 22. The effluent gas 22 is treated by the catalytic converter 30 prior to being released into the atmosphere, therefore, undesirable gases, such as carbon monoxide and unreacted ozone are efficiently converted into carbon dioxide and oxygen.