Abstract: A method of forming a pattern of doped region includes the following steps. At first, a device layout pattern including a gate layout pattern and a doped region layout pattern is provided to a computer system. Subsequently, the device layout pattern is split into a plurality of sub regions, and the sub regions have different pattern densities of the gate layout pattern. Then, at least an optical proximity correction (OPC) calculation is respectively performed on the doped region layout pattern in each of the sub regions to respectively form a corrected sub doped region layout pattern in each of the sub regions. Afterwards, the corrected sub doped region layout patterns are combined to form a corrected doped region layout pattern, and the corrected doped region layout pattern is outputted onto a mask through the computer system.