Hybrid metrology for semiconductor manufacturing is on a collision course with dark uncertainty. An IEEE technology roadmap for this venture has targeted a linewidth uncertainty of +/- 0.17 nm at 95 % coverage and advised the hybridization of results from different measurement methods to hit this target. Related studies have applied statistical models that require consistent results to compel a lower uncertainty, whereas inconsistent results are prevalent. We illuminate this lurking issue, studying how standard methods of uncertainty evaluation fail to account for the causes and effects of dark uncertainty. We revisit a comparison of imaging and scattering methods to measure linewidths of approximately 13 nm, applying contrasting statistical models to highlight the potential effect of dark uncertainty on hybrid metrology. A random effects model allows the combination of inconsistent results, accounting for dark uncertainty and estimating a total uncertainty of +/- 0.8 nm at 95 % coverage. In contrast, a common mean model requires consistent results for combination, ignoring dark uncertainty and underestimating the total uncertainty by as much as a factor of five. To avoid such titanic overconfidence, which can sink a venture, we outline good practices to reduce dark uncertainty and guide the combination of indeterminately consistent results.

翻译：半导体制造中的混合计量学正与暗不确定性发生碰撞。IEEE为此项技术制定的路线图设定了在95%置信水平下±0.17纳米的线宽不确定度目标，并建议通过融合不同测量方法的结果来实现这一目标。相关研究采用了需要结果一致才能降低不确定度的统计模型，然而实际中不一致的结果普遍存在。我们揭示了这一潜在问题，研究了标准不确定度评估方法如何未能考虑暗不确定性的成因与影响。我们重新审视了成像法与散射法测量约13纳米线宽的对比研究，通过应用对比性统计模型来凸显暗不确定性对混合计量学的潜在影响。随机效应模型允许整合不一致的结果，它考虑了暗不确定性并估算出95%置信水平下±0.8纳米的总不确定度。相比之下，公共均值模型要求结果一致才能进行整合，它忽略了暗不确定性，导致总不确定度被低估达五倍之多。为避免这种可能使整个项目沉没的泰坦尼克式过度自信，我们概述了减少暗不确定性并指导不确定一致性结果融合的良好实践。