Aerial imaging qualification and metrology for source mask optimization

As the semiconductor industry moves to 3X technology nodes and below, holistic lithography source mask optimization (SMO) methodology targets an increase in the overall litho performance with improved process windows. The typical complexity of both mask and illumination source exceeds what the lithographic industry has been accustomed to, and presents a novel challenge to mask qualification and metrology. In this paper we demonstrate the latest in aerial imaging technologies of Applied Material's Aera2 TM mask inspection tool. The aerial imaging capability opens the door to a wide variety of metrological measurements analysis at aerial level and provides enabling solutions for mask and scanner qualifications. In particular, we demonstrate core and periphery DRAM pattern process window assessment and MEEF measurements, performed on an advanced test mask.