Stacked polymer patterns imprinted using a soft inkpad

A soft inkpad imprinting technique to produce stacked micrometer and submicrometer polymer patterns on substrates is presented. A thin soft inkpad is used to coat a polymer film onto the protrusions of a surface treated hard mold. The polymer film on the protrusions of the hard mold is then transferred to a substrate. Simultaneously, a negative pattern of the hard mold is formed on the soft inkpad that may also be transferred to a substrate. Numerical simulations are used to study the mechanisms of pattern transfer by soft inkpad imprinting. With the use of polymer blends, both positive and negative polymeric gratings with 700 nm period were produced. The soft inkpad allows multiple transfers of polymers with similar solubilities to the hard mold since no chemical solution is used for coating. High aspect ratio polymer stacks can be formed without alignment. This capability is an important advantage when forming submicrometer and nanometer multiple-layered polymer structures because current nanoimprint systems have limited overlay accuracy. (C) 2004 American Vacuum Society.