Theoretical study on effects of exposure pattern width on line edge roughness and stochastic defect generation in fabrication of 16-nm-half-pitch line-and-space patterns by electron beam lithography

The resolution of electron beam (EB) mask writers has reached a 16 nm half-pitch. The suppression of stochastic phenomena such as line edge roughness (LER) and stochastic defect generation is an important issue in the high-resolution fabrication of photomasks and nanoimprint molds. In this study, the effects of exposure pattern width on LER and stochastic defect generation were theoretically investigated on the basis of the sensitization and reaction mechanisms of chemically amplified EB resists. The exposure pattern width affected stochastic bridging more than stochastic pinching and LER. The optimum pattern widths for the suppression of stochastic bridging in the fabrication of 16-nm-half-pitch line-and-space patterns were 8, 8, 10, and 12 nm for the sensitivities of 300, 240, 180, and 120 µC cm−2, respectively.