Defect Reduction with Advanced Lithographic Filter

It is well known that Nylon membrane can significantly reduce defects on a wafer when it is used in filtration of lithography resist by removing metal ion, particle and gel [1], [2]. With the development of advanced technology nodes, improvement of higher cleanliness and higher retention rating of filters for point-of-use (POU) applications is becoming increasingly necessary. In this study, we present 2 different types of 1nm rating Nylon filter for photoresist filtration, namely standard type and thick type. Filter cleanliness confirmed by liquid particle counter (LPC) and ICP-MS and defect reduction performance on wafer are compared. Evaluation of metal reduction and polymer removal behavior are also studied to clarify the mechanism of defect reduction.