An exploration of the use of fluoropolymers in photofiltration

摘要

Advanced lithography techniques relying on innovations in scanner, track, and material technologies have been aconsistent driver of Moore’s Law. As these innovations transition from laboratories to factories, all members of thelithography value chain must adapt. Filtration technology has relied upon a subset of carefully matched materials tofilter lithographic materials. The introduction of new materials for emerging lithography techniques creates theopportunity to seek alternatives to ultra-high molecular weight polyethylene (UPE), Nylon, and polypropylene.Fluoropolymers, such as polytetrafluoroethylene (PTFE) and perfluoroalkoxy alkane (PFA), have been used widely inthe fab to filter chemistries that require instant surface wettability and high flow rates. These requirements now alignmore closely with today’s leading-edge lithography materials. After a review of the motivation behind choosing newfiltration materials in the lithography sector, this paper will identify the critical material attributes, specific designconsiderations, and the importance of membrane surface technologies, beginning in the photoresist manufacturingprocess. Data presented will include laboratory studies of fluoropolymer membranes in common solvents, on-waferdefect data, and bulk filtration manufacturing data, all showing the match between fluoropolymer filters andphotolithography materials.