ISBN 978-3-8439-0376-9

978-3-8439-0376-9, Reihe Nanotechnologie

Namil Koo
Ultraviolet nanoimprint lithography using flexible molds: Process development and applications

113 Seiten, Dissertation Rheinisch-Westfälische Technische Hochschule Aachen (2012), Softcover, A5

Zusammenfassung / Abstract

Due to the economical and physical limits of optical lithography, various alternative methods have been considered to meet the demands of down-scaling in feature size for various industry applications in the fields of electronic, photonic, and photovoltaics. Extreme Ultraviolet Lithography (EUVL) is a powerful alternative, but EUVL has once again been delayed for the 22 nm half-pitch node due to lack of power source, resists, masks and metrology tools. Additionally, the cost of ownership is still too high.

Therefore, nanoimprint lithography (NIL) has been focused as a powerful alternative technology to optical lithography. NIL uses a patterned mold for the definition of desired patterns, thereby designed patterns can be fabricated without complicated efforts such as complex optic systems or optical proximity correction (OPC).

NIL can be mainly classified into thermal NIL (T-NIL) and UV-NIL processes according to the resist filling/curing system. A new family-tree of NIL incorporating the results of this work is illustrated in Figure 7-1. For all NIL, the initial resist layer must be sufficient to fill the all mold cavities, resulting in a residual resist layer. Tight control of this residual layer thickness (RLT) is of utmost importance for applications where high fidelity in pattern transfer is required. Based on the resist consumption for the filling of mold cavities, a nanoimprint proximity effect can occurr that should be reduced. In addition, particle contamination can cause damage to expensive imprint molds and lead to a depletion area where no patterns are imprinted. High precision alignment techniques are also still a hot issue in NIL.

This thesis aimed at the process development to overcome the limitations of standard soft UV-NIL for the demonstration of high performance soft UV-NIL and to show its high potential for industry applications in electronics and photovoltaics.