Line-edge roughness: characterization and material origin

Among lithographic characteristics, line-edge roughness (LER) of resist patterns now assumes even greater importance than before. This is because the variation of device sizes due to LER cannot be neglected as device sizes shrink. Therefore, LER has to be reduced as much as possible in next-generation lithography. For LER reduction, it is essential to elucidate its cause based on precise evaluations. We have been working to develop methods for the measurement and analysis of LER and elucidate the cause of LER for an electron-beam chain-scission type of resist, which has a simple imaging mechanism. In this report, we describe two LER issues: its characterization and material origin.