Patterning Fidelity Enhancement and Aberration Mitigation in EUV Lithography Through Source-Mask Optimization.

Area of Science:

• Semiconductor Manufacturing
• Lithography Technology
• Optical Engineering

Background:

• Extreme ultraviolet (EUV) lithography is essential for advanced semiconductor manufacturing, enabling smaller technology nodes.
• Scaling below 3 nm presents significant challenges in aberration control and patterning fidelity.
• Current methods struggle to maintain imaging quality and process windows at these critical dimensions.

Purpose of the Study:

• To demonstrate Source-Mask Optimization (SMO) as a solution for aberration control and patterning fidelity in EUV lithography.
• To enhance pattern transfer accuracy and mitigate aberrations for sub-3 nm technology nodes.
• To provide a pathway for maintaining lithographic performance during feature size scaling.

Main Methods:

• Developed a comprehensive optimization framework for Source-Mask Optimization (SMO).
• Integrated key process metrics including critical dimension (CD), exposure latitude (EL), and mask error factor (MEF).
• Applied SMO to 40 nm minimum pitch patterns, representative of 2 nm node back-end-of-line (BEOL) requirements.

Main Results:

• Achieved significant improvements in imaging quality and process window for 40 nm minimum pitch patterns.
• Demonstrated an average reduction in CD uniformity variation of 4.02%.
• Reported a 1.48% improvement in exposure latitude and a 5.45% reduction in mask error factor (MEF).

Conclusions:

• Intelligent SMO implementation enables robust patterning solutions by balancing source characteristics with mask modifications.
• SMO effectively compensates for inherent EUV aberrations, crucial for advanced lithography.
• The proposed aberration-aware SMO strategies are vital for next-generation semiconductor manufacturing.