Customizing Lithography Feature Size With Self-assembled Patterns Of Natural DNA

Over the past decade, there has been increasing interest in micro-fabrication dueto its ubiquitous use in the semiconductor industry, among other new applications,such as micro-fluidic devices, biosensors, tissue engineering, and drug delivery.Photolithography is the most widely used conventional micro-fabrication technique.However, the intrinsic optical diffraction limitation of photolithography makespatterning features smaller than100nm difficult. To overcome this challenge, variouslithographic approaches, such as electron beam lithography, ion beam lithography,and scanning probe lithography, have been developed, but are still cost-andthroughput-deficient. Recently, soft lithography and nanoimprint lithography haveattracted attention because of their high throughput and cost efficiency. A suitablestamp is the basic and critical point in both soft lithography and nanoimprintlithography techniques. Stamp fabrication can be technologically complicated, andneeds specific materials, such as PDMS, quartz, or silicon. Generally, these stampshave a fixed feature size once fabricated.In this work, we conceptually demonstrated a simple yet robust strategy forcontrollably fabricating precisely sized stamps using patterns created fromself-assembled natural DNA.Highly aligned DNA patterns are successfully formed by evaporating aqueousDNA solutions in a specific geometry construction situated on a PMMA substrate.Optical imaging shows that the DNA alignment patterns have highly alignedregularity on a large scale. AFM images reveal that DNA molecules bind together in astraight line on the PMMA surface, the average height and width of single DNAbundles are90.5±30.8nm and878.8±22.2nm, respectively. A negative replica is obtained by transferring the DNA patterns to UPR based onsurface roughness analysis, and a positive copy is transferred to PAM. By controlleddrying and swelling of the PAM stamp, custom size-scalable features are obtained.SEM and AFM images reveal that the achievable range of the pattern feature size is0.25%to200%, and an average height and width of single linear structure on thecontracted PAM stamp are35.2±4.11nm and363.3±17.66nm.Additionally this paper also made some auxiliary work associated with DNA (i.e.,the mechanism of DNA double-helix structure in the formation of PHPMAmorphology based on molecule design): AUTEAB was successfully synthesized, andconfirmed by FTIR and1H-NMR spectra. The DNA molecules get into thepolymerization system by the complex of AUTEAB and DNA. The pomponmorphology of PHPMA is obtained through solution radical polymerization. As aresult, the morphology structure of PHPMA changes from pompon to polyhedron byelution of hydrochloric acid. SEM images show that average diameter of pompons is0.79μm, and polyhedron is decreased to0.65μm, the width of chenille structure is17.53nm. The structure of DNA complex model was established based on calculationand UV spectra, which shows the chenille on PHPMA surface is a spatial structure ofDNA complex. The theoretical width of chenille structure simulated by the model isclose agreement with the practical, demonstrating the availability of the model.This facile strategy of customizing lithography feature size provides a newavenue for controlled and uniform assembly of patterned components with highscalability toward their integration for electronic circuitry on desired substrates, andnanolithography techniques for achieving pattern scalability. Moreover, it is hopefulto contribute in the development of nanotechnology in the future.