A “thiol-ene” photo-curable hybrid fluorinated resist for the high-performance replica mold of nanoimprint lithography (NIL)

Abstract

Functional polyhedral oligomeric silsesquioxane (POSS)-based materials have been developed as an ideal material with high performance for nanoimprint lithography (NIL). A novel fluorinated hybrid resist as a soft mold for NIL, based on thiol-ene photopolymerization, was precisely designed and synthesized and is comprised of fluorinated mercaptopropyl polyhedral oligomeric silsesquioxane (POSS-F-SH) and a diluted crosslinker (2,2,3,3,4,4,5, DCFA 4 ). The obtained fluorinated hybrid resists possess a variety of characteristics desirable for UV-NIL, including low viscosity (16-239 cP), a low bulk volumetric shrinkage (4.8-7.5%) and a good resistance to oxygen inhibition. The cross-linked hybrid resins exhibited high transparency to UV light and resistance to organic solvents. As a soft mold, the excellent mechanical property (Young's modulus: 0.31-1.56 GPa) and low surface energy (14-20.4 mJ m À2 ) of the fluorinated polymers provide a clean mold release without fracture or deformation of the embossed structures. The thermally stability (T d > 300 C) render them capable of being used for both UV and thermal NIL duplication processes. The resultant soft mold exhibited a high resolution patterning capacity with feature sizes in the range of 200 nm to several microns. The economic efficiency of the mold fabrication, as well as the high durability and excellent releasing properties, could be quite valuable in NIL for the high-throughput fabrication of nano-devices.

Fluorinated Oligomers and Polymers in Photopolymerization

“…1H,1H-Perfluoro-1-decylallyl ether and its perfluoro-1-heptyl homologue were synthesized in a one-step process by using fluorinated alcohols and allyl chloride. 159 An interesting example of fluorinated thiol was reported by Lin et al 160 based on the following silsesquioxane (POSS) containing −SH functions:…”

Fabrication of high aspect ratio (> 100:1) nanopillar array based on thiol-ene

“…Due to the excellent mechanical and physical properties, thiol-ene polymer has been used widely as the nanoimprint resist in NIL to fabricate high-resolution nanostructures [29][30][31].…”

A simple approach to preparation of polyhedral oligomeric silsesquioxane crosslinked poly(styrene-b-butadiene-b-styrene) elastomers with a unique micro-morphology via UV-induced thiol–ene reaction

“…45 It was found that the movement of chains was retarded by the presence of POSS. [47][48][49][50][51][52] Thiol-ene reaction has attracted much attention and has been studied in many systems. Furthermore, POSS was only attached to the SBS chain forming new physical crosslinking sites which limited the reinforcing effect for the polymer.…”