Fast thermal aberration model for lithographic projection lenses

Area of Science:

• Optical Engineering
• Computational Physics

Background:

• Thermal aberrations significantly impact lithography precision.
• Existing models for thermal aberrations are computationally intensive, limiting their practical application in real-time design and analysis.

Purpose of the Study:

• To develop a novel, fast, and accurate computational model for simulating thermal aberrations in lithographic projection lenses.
• To enable efficient prediction of thermal aberration effects during the design and manufacturing phases of lithography tools.

Main Methods:

• A novel model simplifies optical intensity calculations using pupil intensity mapping.
• Simplified formulas for temperature calculation were derived to accelerate thermal aberration simulation.
• The model's performance was validated against experimental data from a commercial lithography tool.

Main Results:

• The simulation achieved an R-square value greater than 0.99 when compared to experimental results.
• The proposed model completed simulations in approximately 10 minutes, demonstrating significant speed improvement.
• The model accurately predicts both the magnitude and trend of thermal aberrations.

Conclusions:

• The developed model provides a fast and accurate method for analyzing thermal aberrations in lithographic projection lenses.
• This tool is valuable for optimizing projection lens design and assessing production risks associated with thermal effects.