Wet clean oxidation for optimal line width and LER

Line Edge Roughness (LER) becomes increasingly critical to control at smaller dimensions. LER also becomes worse for smaller line widths and higher aspect ratios. We explored shrinking line width by litho dose, etch recipe, and wet cleans to meet the target line width for 42 nanometer pitch structures, while minimizing the impact to LER. We also demonstrated that for smaller aspect ratios, smaller line widths can be achieved without compromising LER. By changing dose or etch recipe, similar relations between line width and LER, where smaller line widths resulted in sharp increases in LER. To shrink the line, a method of wet clean cycles was demonstrated. One chemistry was used to remove the outer oxide layer, while the second chemistry would oxidize the surface. Repeated cycles would further shrink the line, without negatively impacting LER.