Patent attributes
A method of modeling dose and focus response in lithographic imaging to simulate an optical critical dimension (OCD) metrology system creates simulated aerial images of the object pattern to be transferred to a resist film on the substrate at different focus settings of the metrology imaging system. The method then successively creates simulated images, at different exposure dose and focus settings of the metrology imaging system, of the latent and developed image of the object pattern in the resist film on the substrate, and the etched image of the object pattern in the substrate. The method converts the simulated images into polygons having more than four sides and determines the Fourier spectrum of the polygons simulating the images of the object pattern. Using the spectrum of the polygons simulating the images of the object pattern, the method then creates simulated aerial images of the object pattern developed in the resist film, at different dose and focus settings, as viewed by the OCD metrology system.
