Micromold fabrication for flexible display application

Uniform size, height and poreless micropattern fabrication on a flexible substrate becomes an important factor for electronic paper development. Recently, thin and flexible display has been a main target in display industry. Therefore, for the future industrial application, non-petroleum based and environmentally friendly thin and flexible micromold development is an essential technology for flexible display application. For this application, existence of micro or nanopores is drawback due to the reduction of transmittance by light scattering and leak of carrier solvent. The liquid–liquid demixing process made porous structure of the cellulose acetate (CA) film. The resulting CA films were optically turbid due to the light scattering by the pores. Single solvent process provides optically transparent and smooth surface films. Line, honeycomb, and square shapes of photoresist patterns were fabricated on the silicon wafer with different heights (2 μm and 20 μm). The replicas of the CA-patterns have about the same sizes and heights with respect to those of the photoresist patterns. The cross-sectional field emission scanning electron microscope images exhibit the pore-free CA mold.