Nanoimprint lithography in the cyclic olefin copolymer, Topas®, a highly ultraviolet-transparent and chemically resistant thermoplast

Abstract

Thermal nanoimprint lithography (NIL) of the cyclic olefin copolymeric thermoplast Topas® is demonstrated. Topas® is highly UV-transparent, has low water absorption, and is chemically resistant to hydrolysis, acids and organic polar solvents which makes it suitable for lab-on-a-chip applications. In particular, Topas® is suitable for micro systems made for optical bio-detection since waveguides for UV-light can be made directly in Topas®. In this article full process sequences for spin coating Topas® onto 4 in. silicon wafers, NIL silicon stamp fabrication with micro and nanometer sized features, and the NIL process parameters are presented. The rheological properties of Topas® are measured and the zero shear rate viscosity is found to be 2.16×104 Pa s at 170 °C and 3.6×103 Pa s at 200 °C while the dominant relaxation time is found to be 4.4 s and 0.9 s, respectively. The etch resistance of Topas® to two different reactive ion etch processes, an oxygen plasma, and an anisotropic silicon etch, is found to ...