Observing morphology on surface of poly(methacrylate) in ArF lithography using AFM phase image

摘要

In recent years, ArF lithography has required a half-pitch size (DRAM) of 45 nm or less. To achieve the requirement, line edge roughness (LER) is recognized as one of the most serious problems in lithography today, because LER directly degrades device characteristics and affects system performances. Although the uniformity of polymer film is important for reducing LER, little is known about polymer morphology after coating. In this study, we observed the surface of poly(methacrylate) samples after coating with AFM tapping mode and found specific morphology in the phase images for the first time (the height image was flat).