CD-bias reduction in CD-SEM line-width measurement for the 32-nm node and beyond using the model-based library method

Shishido, Chie; Tanaka, Maki; Osaki, Mayuka

doi:10.1117/12.813948

Cited by 10 publications

(11 citation statements)

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“…We have already applied MBL to photoresist patterns [1] , etched poly patterns [5] , and Si 3 N 4 hard masks [8] , and confirmed the effectiveness of the MBL technique. However, all of these samples had only line and space (LS) patterns.…”

Section: Overviewsupporting

confidence: 57%

“…We employed a double trapezoid model for this investigation, similarly to what we did in our previous study [1] [5] . In these libraries, the sidewall angle (SWA) at upper trapezoid (Tt) and lower trapezoid (Tb) were set as the floating parameters to be estimated, and the other parameters were fixed as shown in Figure 3 in the estimation sequence.…”

Section: Measurement Condition For the Mbl Measurementmentioning

confidence: 97%

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Verification and extension of the MBL technique for photo resist pattern shape measurement

et al. 2011

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In order to achieve pattern shape measurement with CD-SEM, the Model Based Library (MBL) technique is in the process of development. In this study, several libraries which consisted by double trapezoid model placed in optimum layout, were used to measure the various layout patterns. In order to verify the accuracy of the MBL photoresist pattern shape measurement, CDAFM measurements were carried out as a reference metrology. Both results were compared to each other, and we confirmed that there is a linear correlation between them. After that, to expand the application field of the MBL technique, it was applied to end-of-line (EOL) shape measurement to show the capability. Finally, we confirmed the possibility that the MBL could be applied to more local area shape measurement like hot-spot analysis.

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Section: Overviewsupporting

confidence: 57%

Section: Measurement Condition For the Mbl Measurementmentioning

confidence: 97%

Verification and extension of the MBL technique for photo resist pattern shape measurement

et al. 2011

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“…We previously began a study of the MBL approach through collaboration with NIST 6 . Most previous studies improved the measurement accuracy, the physics based mathematical model and the library [7][8][9][10][11] .…”

Section: Introductionmentioning

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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“…[5][6][7][8][9] In previous studies, we showed that the CD bias could be decreased by applying the MBL method to hard-1932-5150/2011/$25.00 C 2011 SPIE mask or resist patterns at the 45-nm technology node. [10][11][12] However, to apply the MBL method to very fine patterns with line widths of <15 nm, some modifications are needed. The conventional MBL method assumes that the right and left edges can be distinguished from each other.…”

Section: Introductionmentioning

confidence: 99%

Accurate measurement of very small line patterns in critical dimension scanning electron microscopy using model-based library matching technique

Shishido

Tanaka

Osaki

2011

J. Micro/Nanolith. MEMS MOEMS

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Our purpose is to reduce the critical dimension (CD) bias for very small patterns with line widths of <15 nm. The model-based library (MBL) method, which estimates the dimensions and shape of a target pattern by comparing a measured scanning electron microscopy image waveform with a library of simulated waveforms, was modified in two ways. The first modification was the introduction of line-width variation into the library to overcome problems caused by significant changes in waveform due to changes in both sidewall shape and line width. The second modification was the fixation of MBL tool parameters to overcome problems caused by the reduction in pattern shape information due to merging of right and left white bands. We verified the effectiveness of the modified MBL method by applying it to actual silicon patterns with line widths in the range 10-30 nm. The CD bias measured by MBL method for three heights (20, 50, and 80%) was consistent with the atomic force microscopy results. The CD biases at all heights were <0.5 nm, and the slopes of the CD biases with respect to the CD were <3%. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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CD-bias reduction in CD-SEM line-width measurement for the 32-nm node and beyond using the model-based library method

Cited by 10 publications

References 0 publications

Verification and extension of the MBL technique for photo resist pattern shape measurement

Verification and extension of the MBL technique for photo resist pattern shape measurement

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

Accurate measurement of very small line patterns in critical dimension scanning electron microscopy using model-based library matching technique

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