Physics-based dry metal–oxide–resist simulations

BackgroundMetal oxide resists (MORs) have demonstrated exceptional performance in high-resolution extreme ultraviolet (EUV) lithography, primarily due to their high EUV absorptivity and minimal blur radius. Innovative solutions involving dry deposition and dry development processes, tailored for MOR, significantly enhance resist compositional control and mitigate pattern collapse. However, photon shot noise and process variations continue to pose substantial challenges in meeting key performance indicators for defectivity and line-edge roughness.AimTo address these stringent requirements, a comprehensive understanding of the multistep MOR patterning process flow and the dry processing mechanisms is essential.ApproachWe introduce a bottom-up modeling approach for MOR, enabling the construction of a physically grounded, module-based digital twin for the photolithography patterning process flow. This platform captures the effects of various process steps on the deposited MOR system, including photon absorption derived from aerial images, secondary electron-induced blurring, post-exposure bake cleavage and cross-linking reactions, progressive dry development characteristics, and scanning electron microscope-based postprocessing insights. Each module is built upon key mechanistic insights and is mathematically formulated using probabilistic algorithms. Model parameters are directly extracted from meticulously designed blanket and checkerboard exposure experiments, ensuring physical relevance without relying on empirical fitting to patterning data.ResultsThe end-to-end model demonstrates strong predictive capability for dose and roughness metrics, including frequency decomposition, and shows good agreement with experimental wafer benchmark data.ConclusionsThe validated model brings mechanistic and physical insights for resists and processes and may help reduce the complexity in MOR optical proximity correction applications.