Resist nano-modification technology for enhancing the lithography and etching performance

The fullerene molecules (i.e., C60 and C70) were incorporated in the SUMITOMO NEB-22 negative electron beam resist to investigate the lithographic and etching performances of the resist. The sensitivity, process window and contrast of the modified resist were found to be improved, while the dilution of resist degraded the sensitivity. The electron beam dose affected the designed line width, and the adulterated resist could print sub-50 nm pattern without the problem of line edge roughness. The etching selectivity of gas (CHF ₃/CF₄) on silicon dioxide and resist, and gas (Cl ₂/O₂) on poly-silicon and resist were evaluated. We found the small amount (0.01-0.02% w/v) of fullerene molecules very effectively promoted the etch resistance and selectivity. The fullerene-incorporated resist was used to pattern self-aligned metal silicides, and nickel silicide on poly-silicon exhibited lower sheet resistance.