Integrated lithographic print and detection model for optical CD

A method of modeling dose and focus response in lithographic imaging to simulate an optical critical dimension (OCD) metrology system comprising:

• providing a pattern of an object to be lithographically printed on a substrate;
• using imaging conditions to be employed in a metrology imaging system, creating 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;
• creating simulated images, at different exposure dose and focus settings of the metrology imaging system, of i) the latent image of the object pattern in the resist film on the substrate, ii) the developed image of the object pattern in the resist film on the substrate, or iii) the etched image of the object pattern in the substrate;
• converting the simulated images of the latent image, developed image, or etched image of the object pattern at different exposure dose and focus settings to polygons having more than four sides;
• determining the Fourier spectrum of the polygons simulating the images of the object pattern at different exposure dose and focus settings;
• using the spectrum of the polygons simulating the images of the object pattern, creating 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;
• and
• evaluating critical characteristics of the simulated object pattern viewed by the OCD metrology system.

An article of manufacture comprising a computer usable medium having computer readable program code means embodied therein for modeling dose and focus response in lithographic imaging to simulate an optical critical dimension (OCD) metrology system, the computer readable program code means in said article of manufacture comprising:

• computer readable program code means for providing a pattern of an object to be lithographically printed on a substrate;
• computer readable program code means for creating 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, using imaging conditions to be employed in a metrology imaging system;
• computer readable program code means for creating simulated images, at different exposure dose and focus settings of the metrology imaging system, of i) the latent image of the object pattern in the resist film on the substrate, ii) the developed image of the object pattern in the resist film on the substrate, or iii) the etched image of the object pattern in the substrate;
• computer readable program code means for converting the simulated images of the latent image, developed image, or etched image of the object pattern at different exposure dose and focus settings to polygons having more than four sides;
• computer readable program code means for determining the Fourier spectrum of the polygons simulating the images of the object pattern at different exposure dose and focus settings;
• computer readable program code means for using the spectrum of the polygons simulating the images of the object pattern, creating 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;
• and
• computer readable program code means for evaluating critical characteristics of the simulated object pattern viewed by the OCD metrology system.

A program storage device readable by a machine, tangibly embodying a program of instructions executable by the machine to perform method steps for modeling dose and focus response in lithographic imaging to simulate an optical critical dimension (OCD) metrology system, said method steps comprising:

• providing a pattern of an object to be lithographically printed on a substrate;
• creating 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, using imaging conditions to be employed in a metrology imaging system;
• creating simulated images, at different exposure dose and focus settings of the metrology imaging system, of i) the latent image of the object pattern in the resist film on the substrate, ii) the developed image of the object pattern in the resist film on the substrate, or iii) the etched image of the object pattern in the substrate;
• converting the simulated images of the latent image, developed image, or etched image of the object pattern at different exposure dose and focus settings to polygons having more than four sides;
• determining the Fourier spectrum of the polygons simulating the images of the object pattern at different exposure dose and focus settings;
• using the spectrum of the polygons simulating the images of the object pattern, creating 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;
• and
• evaluating critical characteristics of the simulated object pattern viewed by the OCD metrology system.