Fabrication of sub 20-nm wide grooves in a quartz mold by space narrowing dry etching

•We demonstrated a simple fabrication process of ultra-fine grooves.•Grooves finer than spaces of resist patterns can be obtained in a quartz substrate.•The groove width narrowing is based on sidewall deposition during sputter etching.•18-nm-Wide grooves were obtained from 85-nm-wide spaces of resist patterns.

This paper describes a simple fabrication process of fine groove structures for quartz molds used in UV nanoimprint lithography. Grooves that are finer than the “spaces” in line/space resist patterns can be obtained on a quartz substrate with the aid of thin Cr layer and a dry etching process using CHF3. The main cause of the groove width narrowing is deposition of fluorocarbon polymer. By changing etching conditions, a large amount of space narrowing is realized. Grooves with widths of 18 nm and 62 nm were successfully obtained from 85-nm and 200-nm wide space resist patterns, respectively.

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