Study on practical application to pattern top resist loss measurement by CD-SEM for high NA immersion lithography

Ishimoto, Toru; Yasui, Naoki; Hasegawa, Norio; Tanaka, Maki; Cheng, Stone

doi:10.1117/12.846541

Cited by 1 publication

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“…This result suggests that top and bottom CDs are correct, however MBL can't estimate correct SWA without knowing the actual height. Further study is underway to detect a photoresist height at resist-loss region for MBL matching 14,15 . …”

Section: Mbl Application To Lithography Process Evaluationmentioning

confidence: 99%

Application of model-based library approach to photoresist pattern shape measurement in advanced lithography

et al. 2010

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The model-based library (MBL) matching technique was applied to measurements of photoresist patterns exposed with a leading-edge ArF immersion lithography tool. This technique estimates the dimensions and shape of a target pattern by comparing a measured SEM image profile to a library of simulated line scans. In this study, a double trapezoid model was introduced into MBL library, which was suitable for precise approximation of a photoresist profile. To evaluate variously-shaped patterns, focus-exposure matrix wafers were exposed under three-illuminations. The geometric parameters such as bottom critical dimension (CD), top and bottom sidewall angles were estimated by MBL matching. Lithography simulation results were employed as a reference data in this evaluation. As a result, the trends of the estimated sidewall angles are consistent with the litho-simulation results. MBL bottom CD and threshold method 50% CD are also in a very good agreement. MBL detected wide-SWA variation in a focus series which were determined as in a process window by CD values. The trend of SWA variation, which is potentiality to undergo CD shift at later-etch step, agreed with litho-simulation results. These results suggest that MBL approach can achieve the efficient measurements for process development and control in advanced lithography.

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Section: Mbl Application To Lithography Process Evaluationmentioning

confidence: 99%