Latent Image Created Using Small-Field Exposure Tool for Extreme Ultraviolet Lithography

Abstract

The small-field exposure tool (SFET) installed at Semiconductor Leading Edge Technologies, Inc. (Selete) is indispensable for the development of resist materials for extreme ultraviolet (EUV) lithography. In the development of next-generation resist materials, the trade-off relationships between resolution, sensitivity, and line edge roughness (LER) are the most serious problems. Among these three features, LER is known to be inversely proportional to the chemical gradient. In this study, we evaluated latent images created using SFET on the basis of EUV sensitization mechanisms. The dependence of the chemical gradient on resolution and sensitivity was clarified for the effective evaluation and development of resist materials. The product of LER and the normalized chemical gradient was roughly estimated to be 0.3–0.6.