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At 1× node, a three-dimensional (3-D) FinFET process raises a number of new metrology challenges for process control, including gate height and fin height. At present, there is a metrology gap in inline in-die measurement of these parameters. To fill this metrology gap, in-column beam tilt has been implemented on Applied Materials V 4iþ critical dimension scanning electron microscope for height measurement. Low-tilt (5 deg) and high-tilt (14 deg) beam angles have been calibrated to obtain the height and the sidewall angle information. Evaluation of its feasibility and production worthiness is done with applications in both gate height and fin height measurements. Transmission electron microscope correlation with an R 2 equal to 0.89 and a precision of 0.81 nm have been achieved on various in-die features in a gate height application. The initial fin height measurement shows less accuracy (R 2 being 0.77) and precision (1.49 nm) due to greater challenges brought by the fin profile, yet it is promising for the first attempt. Sensitivity to design of experiment offset die-todie and in-die variations is demonstrated in both gate height and fin height. The process defect is successfully captured with inline gate height measurement. This is the first successful demonstration of inline in-die gate height measurement for a 14-nm FinFET process control.

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In recent years Hybrid Metrology has emerged as an option for enhancing the performance of existing measurement toolsets and is currently implemented in production 1 . Hybrid Metrology is the practice to combine measurements from multiple toolset types in order to enable or improve the measurement of one or more critical parameters. While all applications tried before were improved through standard (sequential) hybridization of data from one toolset to another, advances in device architecture, materials and processes made possible to find one case that demanded a much deeper understanding of the physical basis of measurements and simultaneous optimization of data. This paper presents the first such work using the concept of co-optimization based hybridization, where image analysis parameters of CD-SEM (critical dimensions Scanning Electron Microscope) are modulated by profile information from OCD (optical critical dimension -scatterometry) while the OCD extracted profile is concurrently optimized through addition of the CD-SEM CD results. Test vehicle utilized in this work is the 14nm technology node based FinFET High-k/Interfacial layer structure.

Until now, metrologists had no statistics-based method to determine the sampling needed for an experiment before the start that accuracy experiment. We show a solution to this problem called inverse total measurement uncertainty (TMU) analysis, by presenting statistically based equations that allow the user to estimate the needed sampling after providing appropriate inputs, allowing him to make important "risk versus reward" sampling, cost, and equipment decisions. Application examples using experimental data from scatterometry and critical dimension scanning electron microscope tools are used first to demonstrate how the inverse TMU analysis methodology can be used to make intelligent sampling decisions and then to reveal why low sampling can lead to unstable and misleading results. One model is developed that can help experimenters minimize sampling costs. A second cost model reveals the inadequacy of some current sampling practices-and the enormous costs associated with sampling that provides reasonable levels of certainty in the result. We introduce the strategies on how to manage and mitigate these costs and begin the discussion on how fabs are able to manufacture devices using minimal reference sampling when qualifying metrology steps. Finally, the relationship between inverse TMU analysis and hybrid metrology is explored. Sendelbach et al.: Effect of measurement error budgets and hybrid metrology. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 05/14/2015 Terms of Use: http://spiedl.org/terms