Relationship between Defects and Stochastic Effect in Chemically Amplified Resists Used for Extreme Ultraviolet Lithography

With the approach of the realization of extreme ultraviolet (EUV) lithography, practical issues such as the defects of resist patterns have attracted attention. In this study, the defects of line-and-space resist patterns were investigated from the viewpoint of the stochastic effects of chemical reactions. The stochastic effect was expressed using the standard deviation σ of the protected-unit concentration. To eliminate bridges within a 6.8 µm length in the line direction, a 1.5–2.0σ difference is required between the average protected-unit concentration and the dissolution point at the center of the space. To eliminate line breaks and severe pinching within a 6.1 µm length in the line direction, a 1.2–1.6σ difference is required between the average protected-unit concentration and the dissolution point at the center of the resist line pattern.