Illumination uniformity correction by using dynamic gray filters in a lithography system.

Area of Science:

• Optics and Photonics
• Semiconductor Manufacturing Technology
• Metrology

Background:

• Illumination-integrated nonuniformity (IINU) critically impacts resolution and critical dimension uniformity in advanced lithography.
• Existing uniformity correction technologies require further enhancement for next-generation semiconductor fabrication.

Purpose of the Study:

• To propose a low-cost, flexible, and high-performance uniformity correction method for advanced lithography systems.
• To demonstrate a novel approach for reducing IINU using dynamic gray filters.

Main Methods:

• Development of a uniformity correction system employing two dynamic gray filters with controllable displacement.
• Analysis of the frequency limitations within the defocus uniformity correction system.
• Application of a particle swarm optimization algorithm for system design.

Main Results:

• The proposed dynamic gray filter system achieved a corrected IINU value below 0.7%.
• Experimental validation confirmed the system's suitability for advanced lithography requirements.
• Demonstrated superior flexibility and correction capability compared to existing methods.

Conclusions:

• The novel dynamic gray filter approach offers a cost-effective and efficient solution for IINU reduction.
• The method provides enhanced flexibility and correction capability, meeting stringent lithography demands.
• This technology advances uniformity correction in semiconductor manufacturing.