Presentation + Paper
22 February 2021 Fast in-device overlay metrology on multi-tier 3DNAND devices without DECAP and its applications in process characterization and control
Author Affiliations +
Abstract
Multilayer stack height in 3DNAND has reached the limit of the aspect ratio that etch technologies can cost-effectively achieve. The solution to achieve further bit density scaling is to build the stack in two tiers, each etched separately. While lowering the requirements on etch aspect ratio, stacking two tiers introduces a critical overlay at the interface between the stacks. Due to the height of each stack, stress- or etch-induced tilt in the channel holes is translated into overlay. Characterizing and controlling the resulting complex overlay fingerprints requires dense and frequent overlay metrology. The familiar electron beam metrology after etch-back (DECAP) is destructive and therefore too slow and expensive for frequent measurements. This paper will introduce a fast, accurate & robust data-driven method for In Device Overlay Metrology (IDM) on etched 3DNAND devices by making use of specially designed recipe setup targets. Also, potential applications for process control improvement will be demonstrated.
Conference Presentation
© (2021) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yaobin Feng, Pandeng Xuan, Dean Wu, Bruce Yang, Craig Xu, Neo Liu, Pavel Izikson, Huanian You, Xi-Zhi Yan, Vladimir Markov, Yvon Chai, Chaoyu Chen, Bert Verstraeten, Amy Wang, Gonzalo Sanguinetti, Giacomo Miceli, Jelmer Boter, Vidar Van der Meijden, Hua Li, and Babak Mozooni "Fast in-device overlay metrology on multi-tier 3DNAND devices without DECAP and its applications in process characterization and control", Proc. SPIE 11611, Metrology, Inspection, and Process Control for Semiconductor Manufacturing XXXV, 116110V (22 February 2021); https://doi.org/10.1117/12.2583416
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