Analysis of Flowing in the Immersion Fluid Field under the Oscillatory Motion of the Silicon Wafer

Abstract

Abstract Immersion lithography has been leading the technology nodes to the sub-20nm regime in recent years. To extend immersion lithography to the sub-10nm technology nodes, the immersion liquid must remain highly pure and flow stably. In immersion lithography, a step-and-scan exposure system is utilized in which the silicon wafer is under an oscillatory motion during the exposure process. It could cause the non-constant flowing of the immersion fluid which affects the stable status of the immersion field and hinders the recycling of the immersion liquid. In this paper, effects of both scanning and stepping motions of the silicon wafer on the flowing of the immersion field are investigated and technical guidance can be obtained to have a high-quality and stable-flowing immersion liquid during the exposure process in the end. Results in this paper can provide theoretical and technical support to the further development of immersion lithography in the near future.