Nanoscale metal pattern-transfer technique using silver ink

• We examined three types of transfer process using silver ink.
• The contact printing can produce separate patterns, but there are resolution.
• The UV-NIL permits high-resolution but the transferred patterns is not separated.
• We developed high-resolution process that utilizes the properties of silver ink.
• A silver hole pattern fabricated by this method acted as a plasmonic color filter.

In our advanced information society, there is an acute need for technological innovation and cost reductions of manufacturing equipment for practical production of devices of the next generation, such as surface-plasmon devices for use in optical equipment and magnetooptic data storage. In a previous study, we used nanoprint lithography with a metal oxide release layer to produce metallic nanopatterns on plastics. In this technique, a transfer metal, such as gold or silver, is deposited by vacuum evaporation, which is a time-consuming process. To overcome this problem, a technique for depositing a metal transfer layer under atmospheric conditions is required. We therefore examined deposition methods using silver ink. Three types of deposition method were examined. The first was contact printing, but this had a limited resolution. The second was ultraviolet nanoimprint lithography, which provided a high resolution, but the silver layer continued along the mold surface shapes. In the third method, to achieve a high resolution and to separate the silver pattern, silver ink on the top regions of the mold surface was removed by a spin coating and hydrophobic treatment. This process successfully gave a high-resolution separated hole pattern that was capable of acting as a plasmonic color filter.

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