Nanoimprint lithography is an attractive technology for LSIs era below 40-n
m critical dimension from the viewpoints of high-throughput and low-cost eq
uipment. In order to avoid a pattern placement error due to thermal expansi
on in the conventional thermal imprint process, we attempted to replicate t
he mold pattern onto a liquid polymer, which was solidified using ultra-vio
let (UV) light irradiation at room temperature. The liquid polymer used her
e was supplied by TEIJIN SEIKI Co., and termed TSR-820. It was spin coated
on slide glass to produce approximately 1.5-mum-thick polymer film. The thi
ckness remained after UV exposure and rinsing in acetone was observed at th
e dose of 10 J/cm(2) and it saturated about a UV exposure dose of 100 J/cm(
2) with an increase in the exposure dose. The mold fabricated of quartz pla
te was first pressed onto the polymer film at about 100 kg/cm(2) and then t
he UV light was irradiated using an imprint apparatus developed for this wo
rk. After releasing the mold from the film, the substrate was rinsed in ace
tone to remove the residual liquid polymer. Eventually the minimum feature
size of 100-nm line and 300-nm space pattern was successfully replicated in
the polymer with good fidelity.