Abstract. Background: Stochastic defects are becoming major concern in the future extreme ultraviolet (EUV) lithography as their probability Pd exponentially increases with decreasing feature size and is highly sensitive to variations in process/mask conditions. Photon shot-noise and discrete/probabilistic nature of materials have been blamed as their causes. Aim: We introduce models for relating Pd to photon and resist statistics under various exposures and material conditions and analyze their impact in future EUV lithography. Approach: Three-dimensional reaction distribution is calculated by a fully coupled Monte Carlo simulation including discrete photon, photoelectron scattering, and resist stochastics. Then probability models predict Pd from statistical data extracted from Monte Carlo results. Results: Stochastic defect generation is enhanced by cascade and/or cluster of correlated reactions among nearby polymers/molecules due to secondary electrons (SE)/acid diffusion and SEs generated along scattered photoelectron trajectories. Pd decreases with increasing reaction density, suppressing effective image blur, and introducing quenchers, where reaction density is limited by SE, photoacid generator, and reaction site. Defect probability increases with decreasing target size for the same k1-factor, while strongly dependent on image slope and defocus. Conclusions: Our analyses suggest that applying EUV lithography to smaller target requires careful material choice, extremely precise process control, and further EUV power enhancement.

中文翻译：

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相关反应的级联和簇是极紫外光刻中随机缺陷的原因

摘要。背景：随机缺陷正成为未来极紫外 (EUV) 光刻技术中的主要关注点，因为它们的概率 Pd 随着特征尺寸的减小呈指数增加，并且对工艺/掩模条件的变化高度敏感。光子散粒噪声和材料的离散/概率性质被归咎于它们的原因。目的：我们介绍在各种曝光和材料条件下将 Pd 与光子和抗蚀剂统计相关的模型，并分析它们对未来 EUV 光刻的影响。方法：三维反应分布通过完全耦合的蒙特卡罗模拟计算，包括离散光子、光电子散射和抗蚀随机性。然后概率模型根据从蒙特卡洛结果中提取的统计数据预测 Pd。结果：由于二次电子 (SE)/酸扩散和沿散射光电子轨迹产生的 SE，附近聚合物/分子之间的级联和/或相关反应簇增强了随机缺陷的产生。Pd 随着反应密度的增加、抑制有效图像模糊和引入猝灭剂而降低，其中反应密度受 SE、光产酸剂和反应位点的限制。对于相同的 k1 因子，缺陷概率随着目标尺寸的减小而增加，同时强烈依赖于图像斜率和散焦。结论：我们的分析表明，将 EUV 光刻技术应用于更小的目标需要仔细选择材料、极其精确的工艺控制以及进一步提高 EUV 功率。