100 nm period gratings produced by lithographically induced self-construction

Abstract

In this paper we report a technique that allows a fast replication of sub-100 nmscale patterns in a thin polymer film on a substrate from a patterned mask. Usingthe new pattern transfer technique, we fabricated 100 nm period polymer gratingswith a 50 nm linewidth above a Si substrate as an example to demonstrate itscapability of producing sub-100 nm nanostructures with direct industrialapplications. In our technique, a mask with protruding patterns is used toinduce similar pattern formation in the molten polymer film through anelectrohydrodynamic instability process. A solid positive replica of the mask isobtained by cooling the polymer below its glass transition temperature. The maskis removed afterwards for the next fabrication procedure. The polymerstructures formed can be used either directly as functional devices or asetching masks for further lithography processes. The mechanism thatleads to the instability and subsequent pattern formation in the polymerlayer is explained. Several important physical parameters that control thewhole instability process are also identified. Our theory and experimentsshow that the pattern transfer technique developed here is well suited forthe fabrication of sub-100 nm surface patterns in thin polymer films.