Top antireflective coating process for 193 nm lithography

Presently for 248 nm lithography, a bottom antireflective coating (BARC) is main method for obtaining better throughput. In the coming 193 nm lithography, substantial critical dimension (CD) control will be required, so that process requirements for improved CD uniformity include minimizing the reflectivity swing amplitude of a resist/BARC/substrate system. Although swing amplitude could be suppressed by using BARC, a simulation clarified that swing amplitude could not be optimized to 0%. This paper evaluates the potential improvements with the addition of an aqueous based top antireflective coating (TARC) to a 193 nm process. A recent material, AZ/sup (R)/ AQUATAR-VI, has been formulated with a refractive index and coating thickness optimized for the process. This TARC is resistant to intermixing with the resist and is removed during the normal develop operation. A logic IC with 0.13 μm design rules will be the primary test vehicle, concentrating on gate levels.