4 April 2014 EUV resists based on tin-oxo clusters
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We have studied the photolysis of tin clusters of the type [(RSn)12O14(OH)6] X2 using extreme ultraviolet (EUV, 13.5 nm) light, and developed these clusters into novel high-resolution photoresists. A thin film of [(BuSn)12O14(OH)6][p-toluenesulfonate]2 (1) was prepared by spin coating a solution of (1) in 2-butanone onto a silicon wafer. Exposure to EUV light caused the compound (1) to be converted into a substance that was markedly less soluble in aqueous isopropanol. To optimize the EUV lithographic performance of resists using tin-oxo clusters, and to gain insight into the mechanism of their photochemical reactions, we prepared several compounds based on [(RSn)12O14(OH)6] X2. The sensitivity of tin-oxide films to EUV light were studied as a function of variations in the structure of the counter-anions (X, primarily carboxylates) and organic ligands bound to tin (R). Correlations were sought between the EUV sensitivity of these complexes vs. the strength of the carbon-carboxylate bonds in the counteranions and vs. the strength of the carbon-tin bonds. No correlation was observed between the strength of the carboncarboxylate bonds in the counter-anions (X) and the EUV photosensitivity. However, the EUV sensitivity of the tinoxide films appears to be well-correlated with the strength of the carbon-tin bonds. We hypothesize this correlation indicates a mechanism of carbon-tin bond homolysis during exposure. Using these tin clusters, 18-nm lines were printed showcasing the high resolution capabilities of these materials as photoresists for EUV lithography.
© (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Brian Cardineau, Brian Cardineau, Ryan Del Re, Ryan Del Re, Hashim Al-Mashat, Hashim Al-Mashat, Miles Marnell, Miles Marnell, Michaela Vockenhuber, Michaela Vockenhuber, Yasin Ekinci, Yasin Ekinci, Chandra Sarma, Chandra Sarma, Mark Neisser, Mark Neisser, Daniel A. Freedman, Daniel A. Freedman, Robert L. Brainard, Robert L. Brainard, "EUV resists based on tin-oxo clusters", Proc. SPIE 9051, Advances in Patterning Materials and Processes XXXI, 90511B (4 April 2014); doi: 10.1117/12.2046536; https://doi.org/10.1117/12.2046536


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