A method of manufacturing a semiconductor device includes randomly placing a plurality of standard cells from a library in which the standard cells are pre-stored, designing an interconnection pattern in which the standard cells are connected randomly to each other, connecting the standard cells according to the interconnection pattern to generate a virtual layout, performing an optical proximity correction operation on the virtual layout using an optical proximity correction (OPC) model, and forming and verifying a mask corresponding to the virtual layout on which the optical proximity correction operation is performed.