Nano edge roughness in polymer resist patterns

Ultrasmall edge roughness in delineated patterns (nano edge roughness) is investigated in nanostructures made of negative‐type electron beam polymer resists by atomic force microscope measurements. Very narrow isolated lines 10–20 nm wide are fabricated with a finely focused electron beam provided by a scanning electron microscope. A chemical amplification novolak resin‐based resist shows nano edge roughness which cannot be neglected in nanofabrication. To investigate the origin of the roughness, conventional two‐component resist systems are microscopically compared. An azide polyvinylphenol‐based resist and an azide novolak resin‐based resist are used. The novolak resin‐based resist exhibits a rougher surface than the polyvinylphenol‐based one. This result suggests that the polymer structures of the base resins cause nano edge roughness of a chemical amplification resist in connection with the acid diffusion during the post‐exposure bake process.

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