Resolution capability of resist patterns and throughput using alkaline treatment under ultrasonic irradiation

Alkaline treatment of the photoresist under ultrasonic irradiation has been investigated to improve the resolution capability of resist patterns with higher throughput. The selectively dissolved phenol resin for the combination of the alkaline treatment with ultrasonic irradiation was increased by 2.3 times compared to the solely alkaline treatment. The sensitizing effect of naphthoquinone diazide (sensitizer) based on phenol was increased to 0.46 against dip treatment of 0.31. As a result, resist sensitivity was increased to 26% and the resolution capability was drastically improved. Consequently, the 0.5 μm line and space resist patterns were resolved completely with fine profile by using the photoresist with a 0.7 μm resolution limit together with g-line exposure machine with a 0.6 μm resolution limit. As a consequence, a high throughput of 25 wafers/min was achieved, which was more than 25 times higher than that of electron beam (EB) lithography.

Combining Thermo-Hydro-Mechanical and Phenol-Resin Impregnation Treatments: Potential for High-Density Poplar Flooring

Thermo-hydro-mechanical (THM) treatments can be used to improve certain properties of underutilized wood species, especially those with low densities. These treatments densify the wood by softening the cell walls using heat, pressure, and moisture but are subject to set-recovery (recovery of compressive deformation) when exposed to humidity. Phenol-based resins have been successful in mitigating this issue when impregnated into the wood. This work explores the use of a new phenol-based resin combined with a THM treatment to limit set-recovery and produce products with the potential for flooring applications. Scratch resistance, hardness, and glue-line shear strength were used to assess the performance. The THM treatment and impregnated phenol resin used in this study increased the scratch resistance, density, and hardness of natural poplar wood and created satisfactory bonding conditions for flooring purposes. With optimization of THM parameters and resin solids content, the resulting product could provide a high-quality flooring material used alone or as a thin laminate from a low-density species like poplar.

Fabrication and Histological Evaluation of Porous Carbonate Apatite Block from Gypsum Block Containing Spherical Phenol Resin as a Porogen

The utility of carbonate apatite (CO3Ap) as a bone substitute has been demonstrated. The feasibility of fabricating macroporous CO3Ap was evaluated through a two-step dissolution–precipitation reaction using gypsum as the precursor and spherical phenol resin as the porogen. Porogen-containing gypsum was heated to burn out the porogen and to fabricate macroporous structures. Gypsum transformed into CaCO3 upon immersion in a sodium carbonate solution, while maintaining its macroporous structure. Next, CaCO3 transformed into CO3Ap upon immersion in a Na2HPO4 solution while maintaining its macroporous structure. The utility of the macroporous CO3Ap for histologically reconstructing bone defects was evaluated in rabbit femurs. After 4 weeks, a much larger bone was formed inside the macroporous CO3Ap than that inside non-macroporous CO3Ap and macroporous hydroxyapatite (HAp). A larger amount of bone was observed inside non-macroporous CO3Ap than inside macroporous HAp. The bone defects were completely reconstructed within 12 weeks using macroporous CO3Ap. In conclusion, macroporous CO3Ap has good potential as an ideal bone substitute.

Decorative Film Formation by Inkjet Printing with Gold Nanoparticles for Synthetic Resin Crafts

The crafts such as lacquerware have made unique strides through decorating techniques using gold such as “Makie”, the technique to draw picture by scattering powdered gold, and “Chinkin”, the technique to rub gold into the design engraved by carving knives. In conventional techniques, practical knowledge and ability are essential to produce craft products. Therefore, screen printing which consists of simple processes has been developed. However, screen printing requires a masking plate made of silk or nylon to create patterns for transcribing ink into objects. This paper presents the formation of a decorative film by inkjet printing with gold nanoparticles for crafts such as lacquerware. The proposed method consists of on-demand process, which makes design changeable without masking. The aims are threefold: 1) to establish a sintering process of gold nanoparticles for acrylonitrile butadiene styrene (ABS) and phenol resin substrates used for synthetic resin products; 2) to characterize the sintered gold film; 3) to examine applicability to industry. The major results obtained are as follows: the appearance and the reflectance spectra of the gold nanoparticle film vary with heat conditions; the proper heat conditions which prevent thermal damage to substrates are the temperature of 373 K or below for the ABS resin substrate, and 423 K or below for the phenol resin substrate, respectively; the gold nanoparticle film possessed a good surface integrity without any voids when the sintering temperature is higher than 323 K for 1 h. Moreover, the film had such a high adhesion to substrates that no separation occurred after cross-cut test; the proposed method applied a lacquerware product made of ABS resin, yielding the decorative film

Novel Synthesis of Nitrogen-Containing Bio-Phenol Resin and Its Molten Salt Activation of Porous Carbon for Supercapacitor Electrode

Nitrogen hybridization is an attractive way to enhance the wettability and electric conductivity of porous carbon, which increases the capacitance of carbon-based supercapacitor, however, there is lack of low-cost methods to prepare the nitrogen-doped porous carbon materials. Herein, a novel facile nitrogen-containing bio-phenolic resin was synthesized by polymerization of the carbamate bio-oil, Phenol and paraformaldehyde. As a precursor of nitrogen-doped porous carbon, the nitrogen-containing bio-phenol resin was activated by the one-step molten-salt method. The resultant nitrogen-doped porous carbon showed a high specific surface area up to 1401 m2·g−1. As a supercapacitor electrode, the nitrogen-doped porous carbons showed specific capacitance of 159 F·g−1 at 0.5 A·g−1. It also exhibited high cyclic stability with 94.8% retention of the initial specific capacitance over 1000 charge-discharge cycles at 1.0 A·g−1. The results suggest that these nitrogen-containing bio-phenol resin provide a new source of nitrogen-doped porous carbon for high-performance supercapacitor electrodes.