A pattern matching technique between a scanning electron microscopy (SEM) exposed pattern image of large-scale integrated fine structures and computer-aided design (CAD) layout data based on the relaxation method is proposed wherein circular arc components are utilized. Edges are extracted from the SEM image and corners in the CAD layout are rounded. The edges in the SEM and CAD layout images are divided into three components: horizontal and vertical straight-line segments, and circular arcs. These components are expressed by bounding boxes; the optimal combination between the SEM and CAD components is then searched by using the probabilistic relaxation method. The mean vector among the obtained shift vectors shows the matching point. We applied our method to SEM exposed pattern images and compared the results with those of the conventional cross-correlation method. The results showed that our method has good robustness against change in shape of exposed pattern. The computation time of our method was comparable to the cross-correlation method. (c) 2005 American Vacuum Society.