• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.184-189
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• 2015

We report a simple way to enhance the size gradient of an imprinted nanopattern through oxygen plasma etching under a nonuniform magnetic field. A sample substrate was placed next to a magnet, and then a nonuniform magnetic field condition was formed around the sample. Using oxygen plasma etching, a line pattern having an initial width of 273 nm was gradually modified from 248 nm at one end to 182 nm at the other end. Controlling the arrangement of the magnet and sample, we could induce a triangular shape size gradient. We verified that the gradually modified nanopatterns we produced are applicable to continual optical property control, showing a possibility to be utilized for optical components such as gratings and polarizers.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.650-650
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• 2013

Although imprinted nanopatterns of organic polymer can be modified by the heat treatment [1], it generally requires high process temperatures and is material-dependent since the heat-induced mass loss of the organic polymer is greatly affected by its chemical characteristics. When oxygen is added during the annealing process, one can reduce the process temperature as well as the dependence of the materials. With the oxygen, line width reduction of a polymer (SU-8) patterns could be accomplished at temperature of as low as $250^{\circ}C$ which was not possible in the heat only process. This oxidative line width reduction can be dramatically promoted with the introduction of oxygen plasma. The oxygen plasma, with its highly-reactive oxygen species, vigorously etches away the organic materials, proven to be extremely effective line with reduction method. It is, however, very hard to control the extent and homogeneity of the etching, particularly of very fine patterns. Here, we report an effective and reliable line width reduction method of imprinted nanopatterns by combined plasma and heat treatment. The merits of this process include the reduction of process temperature, time and material-dependence.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.5
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• pp.357-360
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• 2019

We demonstrate an alignment technology using an imprinting process on an inorganic NiOx film. The aligned nanopattern was fabricated on a silicon wafer by laser interference lithography. The aligned nano pattern was then imprinted onto the sol-gel driven NiOx film using an imprinting process at an annealing temperature of $150^{\circ}C$. After the imprinting process, parallel grooves had been formed on the NiOx film. Atomic force microscopy and water contact angle measurements were performed to confirm the parallel groove on the NiOx film. The grooves caused liquid crystal alignment through geometric restriction, similar to grooves formed by the rubbing process on polyimide. The liquid crystal cell exhibited a pretilt angle of $0.2^{\circ}$, which demonstrated homogeneous alignment.