An optical proximity correction (OPC) method for manufacturing a semiconductor chip including detecting edges of an initial layout pattern and determining an edge violating a mask rule, among the edges, as a target edge, setting a reference control point (RCP) on the target edge, forming a multi-edge by dividing the target edge based on the RCP, setting additional control points on the multi-edge, forming a modified layout pattern by transforming the multi-edge into a curved edge based on the RCP and the additional control points, performing an OPC simulation based on the modified layout pattern, and calculating an edge placement error (EPE) of the modified layout pattern based on a result of the OPC simulation may be provided.