Ultra clean process gas recycling system for plasma process using krypton and xenon

Abstract

Introduction of rare Kr(Xe) gases into ULSI mass production requires the recycling of exhaust gases. We describe a gas pumping system that enables efficient recycling of Kr and Xe gases. A newly developed screw pump is able to exhaust without involving the atmosphere in its exhaust gases. Moreover, this screw pump needs a smaller volume of purge gases to realize clean pumping than conventional dry pumps. A novel bellows pump can compress recycle gases without involving the atmosphere. These pumping systems enable ultra clean process gas recycling system for the plasma process using krypton and xenon.