Next generation ultra clean nylon filter for on-wafer defects reduction enhancement

The electrical microstructures on chips become ever more sensitive to microscopic contaminants as semiconductor technology nodes evolve to require more processing capacity and power efficiency. Strict control of possible defect sources is required to protect sensitive chip patterns. One such source is the lithography material filter itself. In advanced processes such as EUV and ArF, filter cleanliness has become increasingly vital to achieving superior and stable on-wafer defect performance. Filter extractables can result in cone defects, scum defects and other undesirable yield-impacting issues on wafers. In addition to the adoption of a highly retentive media, this next-generation nylon filter delivers superior defect performance via enhanced raw material cleanliness along with advancements in filter cleaning technology. Cleanliness evaluations in this study demonstrate that the newly developed ultra clean nylon filter has lower levels of metallic and organic extractables in organic and acidic solvents. Furthermore, the new filter's high stability and low pH extractables suggest it can be adopted to certain acidic photochemicals such as used in SiARC and BARC applications. Lastly, field photochemical testing shows a reduction in on-wafer defects for this new technology.