5:15 PM - 5:30 PM
[19p-S224-15] Formation of a screen printing mask by femtosecond laser drilling on polyimide films and effect of hole structure on the volume of dispensed resin droplets
Keywords:UV-nanoimprinting,laser drilling,Screen printing
UV nanoimprint lithography (UV-NIL) is expected for a technology to fabricate nanostructures by replication with designed mold patterns. UV-NIL has following two topics. One is that non-fill defects often occurred by trapping air bubbles in some parts of mold recesses and between substrate and mold surfaces. Bubble defect free UV nanoimprinting with a spincoating resin film has been achieved using an easily condensable gas atmosphere of 1,1,1,3,3-pentafluoropropane (PFP). NL-SK1 mainly comprising glycerol 1,3-diglycerolate diacrylate (GDD, viscosity: 12,800 mPa s) is a suitable UV-curable resin for UV nanoimprinting under a PFP gas atmosphere because of little PFP adsorption. Another is to keep a residual layer thickness (RLT) of imprinted pattern constant for subsequent dry etching processes. Jet and flash imprint lithography (J-FIL) in which liquid droplets of UV-curable resin were dispensed using an ink jet dispenser along with mold recess patterns was proposed to fabricate uniform RLT. However, viscosities of UV-curable resins available for J-FIL are limited to approximately 10 mPa s. High volatility of resins with a low viscous needs a jet and flash manner with a certain interval between ink jet and molding steps. We have demonstrated that high viscous UV-curable resin droplets are placed on substrate surface by screen printing. A screen printing mask prepared by laser drilling on polyimide film, named mesh-free plate, is available for discharging resin droplets without undischarged defects. Now in this research, the mesh free plate is originally prepared by femtosecond pulse laser drilling for controlling discharged resin droplets. The influence of the fabricated hole shapes in the screen printing mask on the resin droplets was investigated by microscope observation.