Method Of Micro/nano Imprinting

Patent Publication Number: US 8092737 B2

Title: Method of micro/nano imprinting

Filing Date: September 3, 2008

Priority Date: January 31, 2008

Inventor(s): Jer-Haur Chang, Yuet-Ping Lee, Lon A. Wang, Yung-Pin Chen

Original Assignee / Applicant(s): National Taiwan University

Link to Patent: US8092737B2

Summary:

The present invention provides a method for imprinting micro/nano patterns on a non-planar or curved substrate, while preventing the curved surface from crumbling and obtaining uniform imprinting pressure distribution throughout the whole curved substrate. The set- up of the invention involves a chamber housing a stack comprising a curved substrate, a pre-shaping sealing film having a shape corresponding to the shape of the curved substrate, a mold, and a moldable layer disposed on a surface of the substrate. The pre-shaping sealing film covers the top surface of the curved substrate and divides the chamber into two portions – the first portion, above the pre-shaping sealing film, contains an inlet for introducing nitrogen gas into the chamber. The method involves applying a pressure to the stack when the moldable layer is heated to be in a moldable state and subsequently, cooling and relieving the pressure in the chamber to obtain a micro/nano imprinted curved surface. It has been disclosed that in order to investigate the pressure distribution over a curved imprint field, a pressure-sensitive film Fujifilm Prescale® (LLW type) was placed between a pre-shaping sealing film and the curved substrate, and pressure was applied as per the regular procedure. Fujifilm Prescale® changes color when it is subjected to pressure. The color intensity of Fujifilm Prescale® is directly proportional to the applied pressure. Color density of the pressed film was measured by a densitometer detector and the resulting color density uniformity over the entire curved nanoimprint field under the gas pressure was computed and compared with a similar set-up wherein pre-shaping sealing film was not used. The results indicated that the pre-shaping sealing film provides excellent contact and uniform pressing pressure throughout the whole curved area.