In order to be able to apply the optical proximity correction (OPC) to recent large scale layout data within a realistic time, we have developed rule-based OPC and its verification tool 'Acropolis' which also has simple hierarchical and parallel data processing feature. Acropolis was applied to our 8M Gates ASIC product. The processing time and output GDSII file size was reduced by 1/150 and 1/250, respectively, with the aid of simple hierarchical data processing compared to flat data processing compared to flat dat processing. The verification function detects excess/shortage o exposure and smallness of slope of the exposure profile. It takes one minute to verify a few hundred square micro meters of area. This performance is sufficient for our purpose, because at this moment we do not aim to verify whole OPC results but several critical area picked up by means of cooperation of process engineers and layout designer. Acropolis is integrated in a layout editor Virtuoso. As a result Acropolis becomes very efficient to layout designers, because they can design layout patterns, run Acropolis, examine verification results and, if necessary, modify the pattern in the same design environment.