Filtration condition study for enhanced microbridge reduction

Filtration products utilizing Nylon 6,6 membrane technology have demonstrated effectiveness in reducing microbridge defects in DUV photoresist patterning. The effects of fluid flow characteristics on defect reduction using a point-of-use Nylon 6,6 filtration product are explored. Lower filtration pressure and longer contact time were found to enhance the removal of gel-like microbridge defect precursors during point-of-use filtration of photoresist polymer solution. A kinetic study of high-pressure filtration, where a strong dependency of gel removal on contact time is observed, revealed the gel-like precursors are adsorbed to a greater extent at sites of polar Nylon 6,6 throughout the membrane depth. A study of gel capturing position by ICP-MS for low-pressure filtration, where gel removal is independent of contact time, revealed the gels are captured at the inlet portion of the filter, due to smaller transportation force, as compared to deeper into the filter media depth. These findings will be very useful both in optimizing filter operating procedures and in the development of nextgeneration filtration products, ultimately contributing toward reduced defectivity and increased yield within nextgeneration lithography processes.