ISBN 978-3-8439-2046-9

978-3-8439-2046-9, Reihe Ingenieurwissenschaften

Jung Wuk Kim
Application oriented nano-patterning methods based on the liquid transfer imprint lithography

147 Seiten, Dissertation Rheinisch-Westfälische Technische Hochschule Aachen (2014), Softcover, A5

Zusammenfassung / Abstract

The importance of process methods allowing precise control of patterns in nano meter scale is growing ever, since the technical advancement in present day aims to develop more complex applications demanding the synergy effect between various technologies that is enabled by pattern definition methods for nanoscale structures. Nanoimprint lithography (NIL) is a cost effective pattern replication method with high resolution in nanoscale that is regarded as next generation lithography method for different applications.

The aim of this work is the introduction of a newly developed unique and novel nanoimprint process variation termed as liquid transfer imprint lithography (LTIL). This process exploits the liquid splitting effect, a separation of thin liquid resist layer. Influences of parameters such as thickness of resist layer and velocity during the LTIL process were investigated. It was found that the splitting of liquid resist layers with a split ration of 50% was repeatedly achieved in various ranges of resist layer thickness from µm to nm-scale. The LTIL process was integrated into a lithography tool for substrate conformal imprint lithography (SCIL), a variation of NIL allowing the control of separation speed and automated process. A successful pattern definition over 4´-wafer scale by the combination of LTIL with SCIL was achieved.

The reduction of residual layer for complex pattern design, one of the most important issues for all process variations of NIL, was achieved by the mean of LTIL within this work, as well as pattern definitions of nanoscale structures on non-planar surfaces, µm-scale prepatterned surface or square substrates without a use of additional equipments.

By the use of LTIL, antireflection structures on non-planar multi-crystalline silicon (Si) substrate have been fabricated with a drop in the weighted reflectance down to 5%, a value comparable to the result of antireflection texturing on a flat mono-crystalline Si-wafer. Furthermore, LTIL was adapted to electron beam lithography (EBL) in order to achieve ultra-high resolution by reducing an EBL resist down to 20nm. Highly dense patterns with a period of 20nm and 10nm half pitch were successfully defined by the combination of thinned EBL resist layer and standard CMOS compatible processes.