Relationship between Sensitization Distance and Photon Shot Noise in Line Edge Roughness Formation of Chemically Amplified Resists Used for Extreme Ultraviolet Lithography

Abstract

In the development of chemically amplified resists used for extreme ultraviolet (EUV) lithography, the line edge roughness (LER) is a significant concern. The relationship between the sensitivity and LER is complicated because both the photon shot noise and secondary electron blur affect LER. In this study, the relationship between the sensitization distance and the photon shot noise of chemically amplified resists is investigated. Latent images of the line-and-space patterns with 11-nm half-pitch are calculated using the Monte Carlo method. The effect of the sensitization distance on LER increases with the quantum efficiency of acid generation, namely, the decrease in photons. Although quantum efficiency enhancement is an important strategy in the development of chemically amplified resists, the sensitization distance limits the effectiveness of such an enhancement.