Nanopattern transfer from high-density self-assembled nanosphere arrays on prepatternedsubstrates

Abstract

We have fabricated nanoimprint moulds with high-density well-defined nanopatterns bypattern transfer from self-assembled nanosphere arrays on prepatterned substrates. Silicananospheres of 100 and 25 nm diameter were regularly arranged over large areasin a self-assembling manner by capillary force via a dip-coating technique ontopographically patterned substrates having 220 nm pitch line/space patterns.The nanosphere arrays were used as etching masks, and nanodot arrays with thesame arrangements were created on the silica substrate surfaces by reactive ionetching (RIE). By developing a combined pattern transfer process using Ru andSiOx masklayers and CF4 and O2 RIE, the aspect ratio between the height and diameter of the nanodots made from the25 nm nanospheres is improved to about two. It is demonstrated that the nanopatterns ofthe moulds can be inversely transferred into polymer surfaces reproducibly by UVnanoimprint process.