Development of Novel Photo-Functional Materials Based on Cyclic Oligomers

Abstract

Novel photo-functional materials, such as refractive-index-changing materials, argon fluoride (ArF) resist materials, and electron beam (EB) resist materials, were designed based on the structures of calixarenes, cyclodextrin, and noria. The synthesis and refractive-index properties of calixarene derivatives containing photo-reactive groups, including azobenzene, norbornadiene, anthracene, cinnamate, and chalcone, were examined, and refractive-index changes (Án D 's) of between 0.007 and 0.061 were observed. The synthesis and patterning properties of a single-layer ArF photoresist system of -CD derivative containing t-butyl ester and fluorine were examined, and a well-resolved 100 nm line and space pattern was obtained on a silicon wafer. A new ladder-like macrocycle, noria (water wheel in Latin), was also synthesized and its application as an EB resist material was examined. The noria derivatives noria-COO t Bu containing t-butyl ester groups, noria-BOC containing t-butyloxycarbonyl group, and noria-acetal containing acetal groups had good physical properties and photo-reactivity. EBresist based on noria-COO t Bu and noria-BOC provided clear line and space patterns at a resolution of 70 and 50 nm, respectively.The development of novel photo-functional materials has contributed substantially to progress in the electronic and optoelectronic industries. Photo-reactive groups, such as radical-or cation-polymerizable groups, photo-isomerizable groups, and photo-removable groups, are useful for obtaining ultraviolet (UV)-cured resins, refractive-index-changing materials, and photo-resist materials, respectively. The physical properties of photo-functional materials, such as film-forming characteristics, thermal stability, mechanical properties, and photo-reactivity, depend primarily on the polymer or oligomer structure. Generally, the photochemical reactivity increases with decreasing glass transition temperature (T g ), due to increase of the molecular motion of polymer chains and functional groups.The photo-chemical reactivity of oligomers is usually greater than that of polymers, due to the lower T g of oligomers compared with polymers. However, the mechanical properties, thermal stability and film-forming properties of oligomer derivatives are inferior to those of polymer derivatives. However, if a linear oligomer is changed to a cyclic oligomer by coupling reaction of the two ends, the physical properties of the resulting cyclic oligomer are expected to be superior to those of the linear oligomer. Therefore, we considered that photofunctional cyclic oligomers might combine the advantages of photo-functional polymers and photo-functional oligomers. That is, photo-functional cyclic oligomers might have both high photo-chemical reactivity and good physical properties.Calixarenes are typical cyclic oligomers containing many hydroxyl groups, and are prepared easily by the reaction of phenols with aldehydes (Scheme 1). 1Although it is well known that calixarenes are attractive materials for use as host molecules in th...

Study on resist performance of chemically amplified molecular resists based on cyclic oligomers

“…Recently, Kudo and co-workers succeeded in the synthesis of a new ladder cyclic oligomer "noria" (water wheel in Latin) 6 and reported the synthesis and photochemical reactivity of noria derivatives containing t-butoxycarbonyl groups, 7,8 t-butylester groups, 9 acetal groups, 10,11 and adamantyl ester groups. [12][13][14][15] It was found that these noria derivatives had high photo-reactivity and produced clear line and space patterns with resolutions of 50-70 nm using an EB exposure tool and 26 nm using EUV exposure tool, respectively.…”

“…[12][13][14][15] It was found that these noria derivatives had high photo-reactivity and produced clear line and space patterns with resolutions of 50-70 nm using an EB exposure tool and 26 nm using EUV exposure tool, respectively. [8][9][10][11][12][13][14][15] To enhance the performance of molecular resist materials based on cyclic oligomers, we evaluated their lithographic performances such as sensitivity, resolution and LWR, using EUV and EB exposure systems. Furthermore, we also examined the etching durability of the synthesized molecular resist materials.…”

Study on Resist Performance of Noria Derivatives Modified with Various Protection Ratios of Acetal Moieties by means of Extreme Ultraviolet Irradiation

“…Recently, Kudo and coworkers have succeeded in the synthesis of a new ladder cyclic oligomer "noria" (water wheel in Latin) [13] and reported the synthesis and photochemical reactivity of noria derivatives containing t-butoxycarbonyl groups [14,15], t-butylester groups [16], acetal groups [17,18], and adamantyl ester groups [19][20][21][22][23]. It was found that these noria derivatives have high photoreactivity and produce clear line and space patterns with resolutions of 50-70 nm using an EB exposure tool and 26 nm using an EUV exposure tool [15][16][17][18][19][20][21][22][23]. Moreover, we clarified that the sensitivity of the resist materials was consistent with the structure of the cyclic oligomers such as noria, calixarene dimer, cyclodextrin, and pillar [5]arene [24].…”

Photo‐Reversible Supramolecular Hydrogels Assembled by α‐Cyclodextrin and Azobenzene Substituted Poly(acrylic acid)s: Effect of Substitution Degree, Concentration, and Tethered Chain Length

“…[12,13] The use of light as an external stimulus for responsive systems is of particular interest since light is a non-polluting energy sources and can be delivered remotely, precisely in space and time, and even quantitatively. [14] Moreover, the surface wettability, [15] controllable capture and release, [16,17] and refractive index [18] of the hydrogels and the sol-gel transition [19][20][21][22] can be reversibly modulated with light. In recent years, different strategies have been developed to build up photo-responsive hydrogels.…”