Nano-pattern replication using parylene thin film for optical applications

We propose a nano-pattern replication method using a heat-resistant polymer film for optical applications, such as surface plasmon optics. Parylene was adopted as a replication material because of its good heat-resistance at metal evaporations. The replication preciseness was evaluated by investigating the size error between master patterns and replication patterns. The 5-mum-thick parylene film with line and space (L/S) patterns was used for the investigation. Although there was about 50-80 nm increase of line width at an edge of each parylene line pattern, the pattern transfer preciseness was sufficient for optical application in visible range. The parylene nano-pattern film also showed a good resistance to Au evaporation and strain due to heat was only 0.25%. As an example of an optical application, transmission enhancement from the aperture surrounded by nano-sized concentric corrugations was demonstrated with our parylene nano-pattern film.