Fabrication of 70 nm-sized zero residual polymer patterns by thermal nanoimprint lithography

The formation of a residual layer under the imprinted patterns is commonly observed after the imprinting process. In order to utilize the imprinted patterns into the top-down process, the removal process of the residual layer using oxygen plasma is inevitable. However, the critical dimension of the imprinted patterns can be degraded during the residual layer removal process and this degradation becomes severer for smaller sized patterns. Zero residual layer imprinting therefore has advantages in nano-sized patterning. In this study, 70 nm-narrow polymer patterns with a height of 300 nm were successfully fabricated on a Si wafer without any residual layer using a high aspect ratio template and thin polymer resin layer, after which 70 nm-narrow Cr metal nanowires were formed on the Si wafer through the lift-off process.