11 April 2017 Process margin improvement through finger-print removal based on scanner leveling data
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The next generation technology and emerging memory devices require gradually tighter lithographic focus control on imaging critical layers. Especially in case of BEOL process, big PDO (Process Dependent Offset) from large intra-field topography steps affects the process margin directly. There are couple of scanner options to reduce PDO, such as AGILE which provides several benefits. However, for certain use cases the AGILE sensor may not be the optimal solution.

In this paper, we introduce the concept and development background of iFPC (intra-field Finger Print Correction). iFPC is a scanner option that removes the generic 3D fingerprint seen in the leveling data so that both process dependency and actual wafer topography are not followed during wafer exposure.

In addition, we compare the degree of process margin improvement when applying iFPC compared to that of AGILE on a critical layer. The achieved results demonstrate that by applying iFPC it is possible to gain an additional 15~20nm DoF. In other words, on this use case our feasibility suggests that by removing the generic 3D fingerprint seen in the leveling data, it is possible to achieve a better focus performance than when trying to follow the topography during scanning.

In conclusion, we found another good way to improve the process margin through this comparative experiment. Therefore, our next step will be to setup the methodology to select the use cases where iFPC is the optimal solution.
Conference Presentation
© (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Young Jun Kim, Tony Park, Jeong Heung Kong, Dong Kyung Han, Jin Phil Choi, Young Seog Kang, Se Yeon Jang, Jeroen Cottaar, Jan-Pieter van Delft, Jeroen Rutten, Axel von Sydow, Marcel Bontekoe, Maarten Boogaarts, Arjan Donkerbroek, Ruiyue Ouyang, Balaji Rangarajan, Khalid Elbattay, Andrew Moe, Chung-Yong Kim, "Process margin improvement through finger-print removal based on scanner leveling data", Proc. SPIE 10147, Optical Microlithography XXX, 1014709 (11 April 2017); doi: 10.1117/12.2258184; https://doi.org/10.1117/12.2258184


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