Novel UPE filtration technology for advanced photolithography materials

High resolution, line edge roughness, and sensitivity are the key performance factors to accelerate EUV lithography into high volume manufacturing. EUV is still a developing technology with several intriguing components, such as high NA exposure system and metal oxide resist [1,2]. In terms of cleanliness, the photoresist (PR) and Spin-on carbons (SOC) in underlayers need to have the same level of cleanliness from defect sources to meet the yield targets in the successive photolithography process after exposure. Filtration technology to remove defect sources from raw materials are continuously evolving to adapt to unique behaviors and compatibility of EUV materials. UPE (ultrahigh molecular weight polyethylene) filtration is a critical technology to remove small particles consistently. In this study, UPE filter development is examined to meet the needs of EUV materials. The filter performance was evaluated with underlayer materials. A new design of UPE membrane morphology achieved significant improvements. The details of the extensive experimental result are discussed in the report.