Non-topcoat process development for ArF immersion lithography

Simplified double patterning process with non-topcoat self-freezing resist

“…This result suggests that self-freezing system works properly for double patterning lithography. For ArF immersion lithography, water shedding properties such as advancing contact angle (ACA), receding contact angle (RCA) are important in terms of exposure scan speed 9 and defects such as the bubble and water mark defects 10 . Reducing the level of PAG anion leaching is also critical, because such contamination can cause damage to the immersion lithography tool.…”

Advances in Patterning Materials for 193 nm Immersion Lithography

“…Unlike materials designed for use as topcoat films, the surface-segregating additives for topcoat-free resists can effectively employ protected acidic groups to ensure both high levels of hydrophobicity during exposure and high levels of developer wettability and alkali solubility in the exposed regions during development. The acid-catalyzed deprotection reactions, which convert the hydrophobic, protected acidic group into a hydrophilic, base-soluble group, occur primarily during the postexposure bake and, therefore, do not significantly lower SRCA values and induce film pulling during the exposure process. , Challenges with these resist-type additives include developer wettability in the unexposed regions and bridging and blob defects …”

“…Most of these correlations are consistent with the hypothesis that hydrophobic aggregates can precipitate and attach to a hydrophobic resist surface during development to create blob defects, while the more hydrophilic aggregates of resist-type additives would be more easily rinsed away from a hydrophilic resist surface during development . Accordingly, rinse treatments and alternative development processes have been found to be effective means to reduce the numbers of blob defects. ,,,,,− Alternatively, Hagiwara et al explored removing the hydrophobic additive material from the surface of the resist using an organic solvent in a “selective segregation removal” (SSR) process prior to development of the resist pattern …”