Vectorial pupil optimization to compensate polarization distortion in immersion lithography system

Area of Science:

• Optics and Photonics
• Semiconductor Manufacturing

Background:

• Polarization distortion, including polarization aberration (PA) and thick mask effects, degrades imaging quality in hyper numerical aperture immersion lithography.
• Existing computational lithography methods like robust optical proximity correction and source/mask optimization partially address this distortion.

Purpose of the Study:

• To introduce and validate a novel vectorial pupil optimization (VPO) method for compensating polarization distortion in immersion lithography.
• To enhance lithography imaging quality and pattern fidelity by extending pupil optimization degrees of freedom.

Main Methods:

• Developed an analytical relationship connecting lithography imaging with an active vectorial pupil.
• Employed a gradient-based algorithm to solve the VPO problem.
• Integrated VPO with PA-aware source mask optimization.

Main Results:

• VPO effectively compensates for both projection optics PA and thick mask-induced polarization distortion.
• Simulations show VPO reduces pattern error by 37.2% compared to current pupil wavefront optimization.
• The VPO method demonstrates significant improvement in lithography pattern fidelity.

Conclusions:

• The proposed VPO method offers a powerful approach to mitigate polarization distortion in immersion lithography.
• VPO enhances imaging quality and pattern fidelity, crucial for advanced semiconductor manufacturing.
• This technique provides a new degree of freedom for optimizing lithography systems.