Enhancing lithographic accuracy by mitigating overlay errors via mask-induced thermal and mechanical optimization

As technology nodes continue to shrink, the demand for higher lithographic accuracy in integrated circuit fabrication intensifies. To address the limitations of traditional compensation methods, this study proposes a mask-induced thermal and mechanical optimization approach to mitigate overlay errors, thereby enhancing lithographic precision in emerging techniques such as nanoimprint lithography (NIL) and surface plasmon lithography (SPL). This approach integrates stress application schemes with localized thermal effects, resulting in a range of compensation strategies based on mask-induced thermal-mechanical coupling. Through mathematical modeling and moment balance assumptions, the technique leverages the linear superposition property for overlay error compensation and identifies 20 key compensation parameters through statistical analysis and optimization algorithms. Experimental validation demonstrates that the compensation effectiveness for completely random, linear, quadratic, and higher-order overlay errors reaches 89.18%, 93.05%, 64.75%, and 53.89%, respectively. In 24 rounds of random testing, the average compensation in theXandYdirections was 91.98%, showing strong stability and consistency. Furthermore, finite element method simulations validate the model, revealing a residual overlay error compensation of less than 0.2 nm, with a calculation-to-validation discrepancy under 0.9%, confirming the model's accuracy. This technology provides a reliable solution for overlay error compensation in emerging lithographic techniques like lensless SPL and NIL and offers valuable insights for future research in extreme ultraviolet lithography and deep ultraviolet lithography, with potential applications in integrated circuit lithography and further validation across various mask types and complex exposure areas.