Study of the bottom antireflective coating process using a high-transparency resist for ArF excimer laser lithography

We have investigated the effect of substrate reflectivity and resist transp arency on resist performance in ArF excimer laser lithography with bottom a ntireflective coating (BARC). Both depth-of-focus (DOF) and exposure latitu de in low-transparency (49% per 0.5 mu m thickness) resist were improved as the substrate reflectivity was decreased. However, the DOF and the exposur e latitude decreased, since the resist profile was tapered on the extremely low-reflectivity (similar to 0%) substrate. On the other hand, the DOF of high-transparency (67% per 0.5 mu m thickness) resist was wider than that o f low-transparency resist and was independent of substrate reflectivity. Th e exposure latitude also improved with decreasing reflectivity. High-transp arency resist achieved a 0.75 mu m DOF at 0.15 mu m lines and spaces (L/S) on BARC using a 0.60-NA lens without any resolution enhancement techniques. Good critical dimensional control at 0.15-mu m L/S patterns over the topog raphy with 200-nm step was obtained without significant linewidth variation . Gate etching was successfully achieved down to 0.11 mu m LIS with the etc hing conditions developed for KrF resists.