Defect risks at interfaces of chemically amplified resists in extreme ultraviolet lithography process

Abstract

Abstract In EUV lithography, stochastically generated defects (stochastic defects) are a significant issue. In this study, the formation of the latent images of line-and-space resist patterns was simulated to assess the dependence of defect risks on the conditions of resist interfaces. The protected unit distribution was calculated on the basis of the sensitization and reaction mechanisms of chemically amplified EUV resists using a Monte Carlo method. The pinching and bridging risks were calculated to be 7.4 × 10−3–2.0 × 10−2 and 1.5 × 10−3–2.6 × 10−1, respectively, depending on the boundary conditions of low-energy secondary electrons at the interfaces. Using the obtained defect risks, we roughly estimated that the impacts of interfacial effects on pinching and bridging probabilities for low-energy secondary electrons were more than one order of magnitude and more than six orders of magnitude, respectively. Controlling the low-energy electrons at the interfaces is important for the suppression of stochastic defects.