Relationships between Stochastic Phenomena and Optical Contrast in Chemically Amplified Resist Process of Extreme Ultraviolet Lithography

摘要

The development of extreme ultraviolet (EUV) lithography has been pursued toward the 11 nm node. With the reduction in feature size, the stochastic effect becomes an essential problem in the lithography used for the high-throughput production of semiconductor devices. In this study, the relationships between stochastic phenomena [line edge roughness (LER) and stochastic defect generation] and optical contrast were investigated using a Monte Carlo simulation on the basis of the reaction mechanisms of chemically amplified EUV resists. Optical contrast did not affect the protected unit fluctuation at the boundary between lines and spaces. However, the protected unit fluctuation at the centers of lines and spaces increased with decreasing optical contrast. The stochastic defect generation is basically affected more by the optical contrast degradation than LER.