Simulator of lithography tool for correcting focus error and critical dimension, simulation method for correcting focus error and critical dimension, and computer medium for storing computer program for simulator

A simulation method, comprising:

• obtaining a correcting scaling value used to correct a focus error of a projection optical system in a lithography tool;
• obtaining a correcting bias used to correct a critical dimension error generated in the lithography tool;
• simulating an image formation by the lithography tool, by using a corrected focus, to model a calculated critical dimension of a simulated image, the corrected focus being calculated by multiplying an actual defocus of the projection optical system in the lithography tool by the correcting scaling value, the actual defocus being used to form an actual image by the lithography tool, the actual image corresponding to the simulated image;
• and
• adding the correcting bias to the calculated critical dimension to make the simulated image approximate to the actual image.

A computer-readable medium for storing a computer program for a simulator, the computer program comprising:

• instructions configured to obtain a correcting scaling value within the simulator, the correcting scaling value being used to correct a focus error of a projection optical system in a lithography tool;
• instructions configured to obtain a correcting bias within the simulator, the correcting bias being used to correct a critical dimension error generated in the lithography tool;
• instructions configured to simulate an image formation by the lithography tool, by using a corrected focus, to model a calculated critical dimension of a simulated image within the simulator, the corrected focus being calculated by multiplying an actual defocus of the projection optical system in the lithography tool by the correcting scaling value, the actual defocus being used to form an actual image by the lithography tool, the actual image corresponding to the simulated image;
• and
• instructions configured to add the correcting bias to the calculated critical dimension to make the simulated image approximate to the actual image within the simulator.