High-Absorption Resist Process for Extreme Ultraviolet Lithography

The trade-off relationships among resolution, sensitivity, and line edge roughness (LER) have been the most serious problem for the realization of extreme ultraviolet (EUV) lithography. The enhancement of polymer absorption in combination with an ultrathin resist process is a solution for the trade-off problem. In this study. the relationship between aerial images of incident photons and latent images generated by polymer deprotection in high-absorption resists was investigated by a simulation based on the EUV sensitization mechanisms. Because of the restricted acid diffusion length. the side wall degradation is a problem at 22 nm fabrication. The improvement of aerial image quality significantly improves the side wall profiles. The relationship between the acid generator concentration and latent image duality wits also investigated in terms of side wall angle and LER. By increasing the acid generator concentration from 10 to 30 wt % the extent of LER can be reduced by similar to 17%. [DOI: 10.1143/JJAP.47.8354]