1. A computer-implemented method for automatically creating a target sample plan for optical proximity correction (OPC) calibration with a minimal number of clips, the method comprising using a computing device to perform actions including: defining a sample plan including a plurality of clips, each of the plurality of clips representing portions of an integrated circuit (IC) layout; calculating a total relevancy score of a projected sample plan for the IC layout, wherein the projected sample plan includes a candidate clip representing an additional portion of the IC layout, and wherein the relevancy score is derived from at least one relevancy criterion and a relevancy weight for the at least one relevancy criterion, the at least one relevancy criterion being one of a topology type of a clip, a printing difficulty of a clip, and a dimensional ratio between clips in the projected sample plan; calculating a relevancy score difference between the total relevancy score of the projected sample plan and a total relevancy score of the sample plan without the candidate clip; adding the candidate clip to the sample plan for the IC layout and removing the candidate clip from the plurality of clips in response to the relevancy score difference substantially fitting a non-linear relevancy score function; removing the candidate clip from the plurality of clips without adding the clip to the sample plan for the IC layout in response to the relevancy score difference substantially fitting a linear relevancy score function, wherein the candidate clip not being added to the sample plan indicates that the sample plan includes the minimal number of clips; and generating an OPC model using the sample plan with the minimal number of clips, wherein the sample plan with the minimal number of clips represents the target sample plan, and wherein the OPC model is used to manufacture at least one IC.