Patent ID: 8719739

Claim:
A method for optical proximity correction (OPC) or mask data preparation (MDP) for use with charged particle beam lithography, the method comprising: inputting a desired substrate pattern for a substrate; inputting a desired reticle pattern for a reticle, wherein the desired reticle pattern has been determined from the desired substrate pattern; inputting a preliminary mask model; determining a preliminary set of charged particle beam shots, wherein the determining comprises calculating a calculated preliminary reticle pattern that will be formed on the reticle using the preliminary set of shots, wherein the calculating uses the preliminary mask model, and wherein the calculated preliminary reticle pattern approximates the desired reticle pattern; inputting a final mask model; and modifying the preliminary set of shots, or a set of shots derived from the preliminary set of shots, to create an optimized set of shots, wherein the modifying comprises calculating a final pattern that will be formed on the reticle using the optimized set of shots, wherein calculating the final pattern uses the final mask model, wherein the modifying comprises calculating a substrate pattern that will be formed on the substrate with an optical lithographic process using a mask formed from the optimized set of shots, and wherein the modifying is performed using a computing hardware device.