EUV mask modeling based on a wide-angle full-vector beam propagation method

Area of Science:

• * Computational lithography
• * Semiconductor manufacturing technology

Background:

• * Extreme Ultraviolet (EUV) lithography imaging models are crucial for digital twin simulations.
• * Existing EUV mask models struggle to balance accuracy, efficiency, and memory usage.
• * Accurate simulation of EUV masks is essential for optimizing the lithography process.

Purpose of the Study:

• * To develop an efficient and accurate EUV mask model for lithography simulations.
• * To overcome the limitations of current models in terms of computational cost and memory footprint.
• * To enable large-scale simulations of complex EUV masks.

Main Methods:

• * Proposed an EUV mask model based on the wide-angle full-vector beam propagation method (WA-FVBPM).
• * Integrated WA-FVBPM with the transfer matrix method and plane-wave expansion.
• * Employed optimized Padé approximation and alternating direction implicit differentiation for acceleration.

Main Results:

• * Achieved acceptable computational accuracy with a critical dimension (CD) relative error < 0.8% for a 24.4 nm contact array pattern.
• * Demonstrated significant improvements over the finite-difference time-domain method: ~200x faster and 100x less memory.
• * Enabled accurate calculation of EUV lithography aerial images within the Abbe imaging framework.

Conclusions:

• * The WA-FVBPM-based EUV mask model offers superior efficiency and reduced memory consumption.
• * This advanced model facilitates large-scale simulations of complex EUV masks, crucial for full-chip analysis.
• * The method shows significant potential for advancing EUV lithography simulation capabilities.