Quencher Effects at 22 nm Pattern Formation in Chemically Amplified Resists

The trade-off between line edge roughness (LER), sensitivity, and resolution is the most challenging issue associated with the development of resist processes for extreme ultraviolet (EUV) lithography. It has been reported that quenchers (basic compounds) affect the sensitivity, resolution, and extent of LER. However, the details are still unclear. In this study, the effects of quencher diffusion constants in 22 nm pattern formation were investigated by a simulation based on the reaction mechanism of chemically amplified EUV resists. For the suppression of line width expansion due to acid diffusion, mobile quenchers are effective. The quality of a latent image is also improved with the increase in diffusion constant. However, the high mobility of quenchers increases the pattern dependence of line width. The same order of diffusion constants for acids and quenchers are preferable for 22 nm fabrication.