We prepared partly crystalline polydiacetylenes (PDAs) by the solid-state polymerization of substituted benzyl 10,12-alkyldiynoates followed by the dissolution of the resulting polymers in refluxing 1,2-dichlorobenzene and subsequent reprecipitation. The obtained PDAs were soluble in organic solvents, such as chloroform and tetrahydrofuran, at room temperature. They showed thermochromism not only in the bulk and polymer matrices but also in solution. The UV–vis absorption spectrum of PDAs in solutions changed depending on the temperature along with a large hysteresis. The thermochromic properties were dependent on the structure of the PDAs, that is, the length of the alkyl side chains and also the structure of the substituent on the phenyl group. We have found that aggregates are formed in the solution when the temperature decreased on the basis of the NMR and dynamic light scattering measurement results.

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We investigated the molecular packing structure and the solid-state polymerization behavior of diacetylene compounds containing a naphthylmethylammonium carboxylate group in the side chain, which forms robust and two-dimensional hydrogen bond networks. The resulting polydiacetylenes (PDAs) showed thermochromic behaviors dependent on the structure of the substituents in the side chain. The maximum wavelength of the absorption bands in the UV-vis spectra of the poly(m,0-DA-Naph)s, which were obtained by the polymerization of the 1-naphthylmethylammonium 2,4-alkadiynoates (m ) 4-13, 16), shifted to a longer wavelength region with an increase in the alkyl chain length of the side chain. The poly(m,0-DA-Naph)s showed a reversible color change upon heating in a temperature range wider than that for poly(1-naphthylmethylammonium 10,12pentacosadiynoate) [poly(12,8-DA-Naph)] due to the different position of the two-dimensional hydrogen bond network supporting the chain structures in the solid state. We further investigated the structure and chromatic properties of PDAs containing the phenylene substituent groups that are directly connected to the conjugating main chain. Eventually, we found the occurrence of the solid-state polymerization of the 4-carboxyphenylsubstituted diacetylenes as not only naphthylmethylammonium salts (m,Ph-DA-Naphs, where m ) 8, 10, 12, and 16), but also precursor carboxylic acid derivatives (m,Ph-DA-CO 2 Hs). The poly(16,Ph-DA-Naph)s showed a reversible color change upon heating, but the mechanism was different from that of the other PDAs. The thermochromism of poly(16,Ph-DA-Naph) included the conformational changes in the aromatic substituent and the conjugating backbone structure.

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This paper proposes a promising approach to break the resolution (R), line-edge-roughness (LER), and sensitivity (S) trade-off (RLS trade-off) relationships that limit the ultimate lithographic performance of standard chemically amplified resists (CAR). This is accomplished in a process that uses a Photosensitized Chemically Amplified Resist TM (PSCAR TM) ** in combination with a flood-exposure in an in-line track connected to a pattern exposure tool. PSCAR is a modified CAR which contains a photosensitizer precursor (PP) in addition to other standard CAR components such as a protected polymer, a photo acid generator (PAG) and a quencher. In this paper, the PSCAR concept and the required conditions in resist formulation are carefully explained. In the PSCAR process, the sensitivity improvement is accomplished by PAG decomposition to selectively generate more acid at the pattern exposed areas during the flood exposure. The selective photosensitization happens through the excitation of the photosensitizer (PS) generated by the deprotection of the PP at the pattern exposed areas. A higher resist chemical gradient which leads to an improved resolution and lower LER values is also predicted using the PSCAR simulator. In the PSCAR process, the improved chemical gradient can be realized by dual acid quenching steps with the help of increased quencher concentration. Acid quenching first happens simultaneously with acid catalytic PP to PS reactions. As a result, a sharpened PS latent image is created in the PSCAR. This image is subsequently excited by the flood exposure creating additional acid products at the pattern exposed areas only. Much the same as in the standard CAR system, unnecessary acid present in the non-pattern exposed areas can be neutralized by the remaining quencher to therefore produce sharper acid latent images. EUV exposure results down to 15 nm half pitch (HP) line/space (L/S) patterns using a PSCAR resist indicate that the use of PSCAR has the potential to improve the sensitivity of the system while simultaneously improving the line-width-roughness (LWR) with added quencher and flood exposure doses. In addition, improved across-wafer critical dimension uniformity (CDU) is realized by the use of a PSCAR in combination with a flood exposure using pre α UV exposure module.