12 May 2004 Immersion lithography fluids for high NA 193 nm lithography
Author Affiliations +
Abstract
Immersion lithography has become attractive since it can reduce critical dimensions by increasing numerical aperture (NA) beyond unity. Among all the candidates for immersion fluids, those with higher refractive indices are desired. However, for many of the fluids, the strong absorption at 193nm becomes a serious problem. Therefore, it is essential to find a fluid that is transparent enough (with absorbance less than 0.5mm-1) and has high refractive index (above water, 1.44) at 193nm. Characterization of various fluid candidates has been performed and the absorbance of these fluids has been measured. To measure the absolute refractive index, a prism deviation angle method was developed. This method offers the possibility of measuring fluid refractive indices accurately. This paper also presents the obtained refractive indices of these fluids. Several candidates have been identified for 193nm application with refractive indices near 1.55, which is about 0.1 higher than that of water at this wavelength. Cauchy parameters of these fluids were generated and approaches were investigated to tailor the fluid absorption edges to be close to 193nm. The effects of these fluids on photoresist performance were also examined with 193nm immersion lithography exposure at various NA's. 1.5 NA was obtained to image 32nm lines with phosphoric acid as the immersion medium. These fluids are potential candidates for immersion lithography technology.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jianming Zhou, Jianming Zhou, Yongfa Fan, Yongfa Fan, Anatoly Bourov, Anatoly Bourov, Neal Lafferty, Neal Lafferty, Frank Cropanese, Frank Cropanese, Lena Zavyalova, Lena Zavyalova, Andrew Estroff, Andrew Estroff, Bruce W. Smith, Bruce W. Smith, } "Immersion lithography fluids for high NA 193 nm lithography", Proc. SPIE 5754, Optical Microlithography XVIII, (12 May 2004); doi: 10.1117/12.602533; https://doi.org/10.1117/12.602533
PROCEEDINGS
8 PAGES


SHARE
Back to Top