Test Pattern for Contour Calibration in OPC Model Build

A method of calibrating a lithographic process model is provided. The method includes providing a test pattern that includes a plurality of shapes; transferring the test pattern onto a photo-mask forming a resist image of the test pattern using the photo-mask; collecting model calibration data from the resist image; and calibrating the lithographic process model using the model calibration data, wherein the plurality of shapes of the test pattern have at least a first shape and a second shape, and distances from an edge of the first shape to an edge of the second shape over a range thereof, when being measured parallel to each other, differ from each other.