Kiyoharu Tsutsumi

Influence of casting solvents on microphase-separated structures of poly(2-vinylpyridine)-block-polyisoprene

Abstract Influences of casting solvent on the microphase-separated structures of poly(2-vinylpyridine)-block-polyisoprene films were studied by transmission electron microscopy and small-angle X-ray scattering. The variations of the structures obtained were consequences of vitrification of microdomain structures developed during the solvent casting processes. The various microphase-separated structures were properly understood by considering the Hansens solubility parameters of the solvent and the copolymer, which quantify the polymer–solvent interactions in the system.

Radical polymerization behaviour of macromonomers: 3. Effect of macromonomer concentration

Abstract The radical polymerization of a polystyrene macromonomer having a methacryloyl end group (with an Mn of 2700), was investigated at various macromonomer concentrations ([M]), in order to study in detail the effect of [M] on the polymerization behaviour. The polymerization rate (Rp), the degree of polymerization (DP), the concentration of the propagating radical ([M∗]), and the initiator efficiency (f) were evaluated by gel permeation chromatography, using an instrument equipped with a laser light scattering detector (l.s.-g.p.c.), and also by electron spin resonance (e.s.r.) spectroscopy. The viscosity of the polymerization solution (η) was also measured, by using an Ubbelohde viscometer. The DP of the formed poly(macromonomer)s changes drastically with [M]. The order of Rp and R p o 1 2 η , with respect to [M], was 2.2 and 1.3, respectively, where oη is the ratio of η of the polymerization system to that of the solvent. This indicates that η alone is not responsible for an order of Rp that is larger than unity. Values for the propagation rate constant (kp) were approximately constant with respect to [M], while those of the termination rate constant (kt) rapidly decreased with increases in [M]. These results are discussed in terms of [M], η, and the segment density around the propagating radical site.

Advanced materials for 193-nm resists

Acrylate monomers containing alicyclic side chains featuring a series of polar substituent groups were assumed to be model compounds. Solubility parameters were calculated for the corresponding acrylate polymers. These acrylate monomers were synthesized using a novel aerobic oxidation reaction employing N-hydroxyphtalimide (NHPI) as a catalyst, and then polymerized. These reactions were confirmed to be applicable for the mass-production of those compounds. The calculation results agreed with the hydrophilic parameters measured experimentally. Moreover, the relationship between the resist performance and the above-mentioned solubility parameter has been studied. As a result, a correlation between the resist performance and the calculated solubility parameter was observed. Finally, resolution of 0.13-micron patterns, based on the 1G DRAM design rule, could be successfully fabricated by optimizing the solubility parameter and the resist composition.

Novel molecular glass photoresist materials for next-generation lithography

A series of Adamantanephenol derivatives was synthesized from adamantinetriphenol / adamantinetrimethylhydroquinone and vinylether compound. Solubility for resist solvent or alkali developer of those materials and thermal properties were examined. Adamantanetrimethylhydroquinone cross-linked with divinylether (AmHQ-CL) had excellent properties as positive tone resist material. We evaluated lithographic properties of AmHQ-CL with photo acid generator and base. Line and space pattern was formed with EB exposure followed with post exposure bake and alkali development. Pattern of smooth wall surface was obtained by removing high molecular weight component from AmHQ-CL. Line width roughness (LWR) of the pattern AnHQ-CL nMWD was less than 30 nm. It was very small value compared with that of traditional polymer resist.

193-nm single-layer resists based on advanced materials

Recent advances in the 193-nm single-layer resist for forming finer patterns have led us to search for new resist materials for the ArF excimer laser. We describe novel, mass productive single layer resist based on hybrid hyper lactonic polymer which has high resolution, good hydrophilicity, and dry etch resistance. Further, we investigate the lactonic polymer, which has Mass-productive Ultimate Norbornyl group with Outstanding Solubility (MUNGOS).