The DP process can be carried out on an OCNL540 substrate before
curing. Again, we used a negative tone mold with a line pattern
(1-lm line width and 2-lm spacing), and a 300-nm pattern
height. The mold was coated with a F-ASL formed by OPTOOL
HD-1100TH. The OCNL540 was spin-coated onto the Si substrate
giving a film thickness of about 200 nm. An imprinting pressure
of 5 MPa was maintained for 60 s. Fig. 4(a) shows an SEM image
of the imprinted pattern on the OCNL substrate after DP-RT
nanoimprinting. Although the pattern was moved, the second pattern
was successfully imprinted over the first imprinted lines. In
addition, we fabricated a cross-pattern by DP-RT nanoimprinting
using two types of the molds: a 600-nm-spaced pattern and a
350-nm line width and 400-nm-spaced pattern. The first imprinting
was carried out using the 200-nm line width and 600-nmspaced
pattern. We then performed the second imprinting using
the 350-nm line width and 400-nm-spaced pattern perpendicular
to the first imprinted pattern, as shown in Fig. 4(b). In this case,
the first pattern was slightly deformed. These results indicate that
suitable materials need to be developed in order to optimize the
DP-RT nanoimprinting process. Nevertheless, we have successfully
demonstrated the viability of DP-RT nanoimprinting.