The Fabrication (Fab) layout design is a strategic issue and has a significant impact on the operational efficiency of semiconductor manufacturing. This research work was motivated by the actual problem to analyse and disperse the congested material flows of central corridor caused by an automated material-handling system (AMHS) in the spine-structure Fab of S Electronics in Korea, which is currently in mass production. In this paper, we suggest an efficient Fab facility layout determination method using genetic algorithm, while considering the interrelationship between manufacturing processors and AMHS. Specifically, we devise a special fitness function employing traffic congestion penalty for reverse and cross-material flows in addition to the usual material-handling distance. By using numerical experiments, we show the superiority of the suggested approach for reducing the overall distance of congested material handling by decreasing the reverse and cross-flows, which cause traffic congestions in the central corridor and entire Fab as well. We expect that this method is expected to be helpful in solving the Fab process layout problems at the Fab planning stage in the actual industrial field.