## 3 Results and Discussion
### UV Curing Nanoimprint Lithography  
The repeatable properties of producing lines and trenches with a 500 nm contact hole and 2 um line patterns on the surface of TPU-UL were evaluated, to observe the effect of reducing the defect numbers on the template in the replication of nanoimprint process cycles. The same template was used to imprint TPULR4.5 and TPULR0 over 20 times. Figure 4 shows the optical microscope images of the template with a 500 nm contact hole and 2 um line patterns in TPULR4.5 containing 4,4,5,5,6,6,7,7,8,8,9,9,10,11,11,11-heptadecafluoro-2-hydroxyundecyl acrylate as a UV reactive fluorine surfactant and TPULR0.  
\begin{table}
\begin{tabular}{l l l l l} \hline
**Resist material** & \(\mathbf{\gamma_{\mathrm{s}}}\) & \(\mathbf{\gamma_{\mathrm{S}}^{\mathrm{d}}}\) & \(\mathbf{\gamma_{\mathrm{S}}^{\mathrm{p}}}\) & \(\mathbf{\gamma_{\mathrm{S}}^{\mathrm{h}}}\) \\ \hline TPULR0 & 47 & 27 & 12 & 8.1 \\ TPULR4.5 & 20 & 16 & 3.6 & 0.1 \\ TPULR9 & 22 & 21 & 0.5 & 0.0 \\ \hline \end{tabular}
\end{table}
Table 3: Surface free energy components of TPULR9, TPULR4.5, and TPULR0.  
The resist patterns of the referenced TPULR0 without a UV reactive fluorine surfactant were non-imprinted after one imprint and almost part of the resist patterns was observed on the template. The template separation failure was considered to be due to the fact that the adhesion between TPULR0 and template was stronger compared with that between TPULR0 and the underlayer material TPU-UL, in the case of no approach to use a coated fluorinated self assembled monolayer on the surface of template.  
On the other hand, no noticeable changes on the template with a non-coated fluorinated self assembled monolayer after 20 nanoimprint process cycles were achieved by using the developed TPULR4.5 on TPU-UL. TPULR4.5 on TPU-UL indicated excellent patterning dimensional accuracy in the replication of 20 nanoimprint process cycles. Anti-adhesion was found between the template and TPULR4.5 containing a UV reactive fluorine surfactant. The nanoimprint lithography over 20 nanoimprint process cycle times can be expected to give good repeatability and durability. The surfactant 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoro-2-hydroxyundecyl acrylate as a template release component included in TPULR4.5 was confirmed to be effective for the reduction of contamination and defect of nanoimprint resist material on the template,and thus as a clean separation technology for mass-production using UV curing nanoimprint lithography. It was also believed that  
Figure 4: Optical microscope images of (**a**) template and (**b**) nanoimprint resist material on underlayer with 500 nm contact hole and 2 μm line patterns.  
this approach to use the developed nanoimprint resist materials containing UV reactive fluorine surfactants, produced high fidelity replication by defect reduction, with a single polymeric material as a disposable nanoimprint template instead of quartz or silica templates.  
The common surface modification technique in nanoimprint lithography applied a fluorinated self assembled monolayer on the template. The fluorinated self assembled monolayer reacts with the free silanol groups on the surface of the quartz template in a condensation reaction to form a single layer of fluorinated alkyl chains. The treatment using a fluorinated self assembled monolayer is found to degrade after repeated nanoimprints, suggesting a breakdown or erosion of the fluorinated monolayer [13,14]. The used template surface in this study was not treated with a common fluorinated self assembled monolayer. Future study to reduce the defects generated from de-molding is expected; in addition to use of a common fluorinated self assembled monolayer on the template.