Vinyl ethers in ultraviolet curable formulations for step and flash imprint lithography

Abstract

Until now, acrylates have been the monomers of choice for use for step and flash imprint lithography ͑SFIL͒ etch barrier formulations, in part because of the commercial availability of silicon-containing acrylates ͑necessary for etch resistance͒, together with their low viscosities and capability for rapid photopolymerization. However, despite many desirable properties, the polymerization of acrylates via radical chain propagation causes some potential issues in the SFIL process as a result of the inhibition of these processes by oxygen. Vinyl ethers are prime candidates to replace acrylates. Their curing proceeds by a cationic mechanism, which is insensitive to oxygen and very rapid, while the vinyl ether group contribution to viscosity is significantly lower than that of an acrylate, silicon-containing vinyl ethers are not widely commercially available, and so were synthesized for this study. As expected, formulations based on these vinyl ethers were lower viscosity and faster curing than the acrylate etch barrier formulations presently employed, while the tensile strength of cured vinyl ether formulations were found to be higher than their acrylate counterparts. In spite of about twice higher template separation force compared with acrylates, the tensile strength of vinyl ether etch barrier formulations is about five times higher than that of acrylate formulations. Therefore, these vinyl ether-based formulations were used to pattern down to 50 nm features using the SFIL process.

Photocurable Silsesquioxane-Based Formulations as Versatile Resins for Nanoimprint Lithography

“…41 It implies that the imprinted sub-50-nm feature structures with these SSQMA-based formulations would be rigid enough to resist failures, making these formulations appropriate for UV-based NILs. [23][24][25] 3.2. Application of SSQMA-Based Formulations as UV Nanoimprint Resins.…”

Nanoimprint Lithography: A Processing Technique for Nanofabrication Advancement

“…The resist has the following properties: inherent properties of the resist (with a good substrate adhesion, low shrinkage, low viscosity), coating properties (controllable thickness in the 50∼500 nm, smooth surface, surface roughness is less than 5 nm) and good resistance to etching (at least 1:3 etch selectivity, relative to Si or SiO 2 ) [22][23][24][25].…”

Temperature stability of electro-optic properties of polymer dispersed liquid crystal with different crosslinking monomer in PN393 base pre-polymer

“…However, we presume that the degree of polymerization would be relatively low in acrylate-PDLC (TMPTAand HDDA-) due to the oxygen inhibition effect. It is known that the polymerization of vinyl ether-based formulation is not affected by oxygen dissolved in the mixture [7]. Therefore, DEGDVE can lead to higher degree of polymerization so that the immiscibility gap is much wider.…”