Evaluating SEM-based LER metrology using a metrological tilting-AFM

In this study, we developed a methodology to evaluate scanning electron microscopy (SEM)-based line edge roughness (LER) metrology. In particular, we used a metrological tilting atomic force microscopy (tilting-mAFM) as LER reference metrology. We analyzed the height-height correlation function (HHCF) of SEM line-edge profiles combining averaging and unbiased correction methods. The direct comparison of our method with tilting-mAFM enabled a precise evaluation of the SEM-based LER metrology. We demonstrated that a combination of unbiased HHCF and averaging methods with appropriate condition enabled relatively precise measurement of three roughness parameters. We observed that, for precise roughness evaluation, reducing noise in the line-edge profiles is important before performing the HHCF analysis and unbiased correction.

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