Relationship between absorption coefficient and line edge roughness of chemically amplified resists used for extreme ultraviolet lithography

Abstract

The development of resist materials used for extreme ultraviolet (EUV) lithography has steadily progressed since 2005. Their resolution and sensitivity are now close to those required for the high-volume production of semiconductor devices. However, the line edge roughness (LER) must still be reduced to achieve the required value. For the reduction of LER, increasing the absorption coefficient is an important strategy. In this study, the relationship between the absorption coefficient and LER was investigated on the basis of the sensitization mechanisms of chemically amplified resists. The relationship was found to depend on the acid generator concentration, half-pitch, and sensitivity. Assuming a required sensitivity of 10 mJ cm -2, absorption enhancement is effective for reducing LER, particularly at the 11 nm node. © 2012CPST.