Fabrication of Large Area Complex Nanopatterns and Their Applications as High Efficient Sensing Substrate

Abstract

One of the important goals in nanolithography is to efficiently reproduce many of the characteristics of the lithographic patterns applied for electronic, optical, magnetic, chemical and biological sensors and devices. In this thesis, two novel nanolithographic strategies and their applications are discussed, one is block copolymer (BCP) lithography used for effective biosensing substrate and the other is capillary force lithography used for DNA nanoarray stamping, single magnetic domain study, and enhanced fluorescence detection. When BCP is used as a lithographic template, the resultant nanostructure offers elements with characteristic dimensions of ~10 nm so as to achieve molecular-level process control of bioarrays. This biofunctionalized template provides a useful tool for elucidating recognition events between carbohydrates and proteins at a molecular level, resulting in enhanced biosensor performance. As another patterning strategy, this thesis describes the novel method for creating many different complex structures from a single prepattern in capillary force lithography (CFL). Although non-photolithographic including CFL approach has made enormous progress in terms of reproducibility and uniformity, it still requires high cost to meet the necessary of various patterns of masters. Our method accomplishes various metal patterns from a single pattern with isolated dots by simply varying the residual polymer film thickness and the reactive ion etching (RIE) time. Next, large area DNA printing based on a stamping method (Supramolecular Nano-stamping, SuNS) was achieved starting from the features of various shapes and dimensions made by CFL. We present an introduction of composite substrates to SuNS. By using the composite of gold film coated on elastomeric substrate, the flexible character of elastomer (PDMS) allowed for substantially improved printing coverage to SuNS (>50$mm^2$ ) in facile manner. Also, we report successful fabrication of pe...