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Hosaka, Yuji*; Oyama, Tomoko; Oshima, Akihiro*; Enomoto, Satoshi*; Washio, Masakazu*; Tagawa, Seiichi*
Journal of Photopolymer Science and Technology, 26(6), p.745 - 750, 2013/12
Times Cited Count：11 Percentile：34.89(Polymer Science)ZEP520A is one of the most popular positive electron beam (EB) resists used in research and photomask fabrication owing to its excellent properties. Herein, EB-induced initial reactions of ZEP520A were investigated via pulse radiolysis (EB energy: 28 MeV, time resolution: 10 ns). Dissociative electron attachment and formation of a charge transfer complex were definitive contributing factors to the efficient degradation of ZEP520A. Furthermore, products induced by direct ionization of ZEP520A were observed in a highly concentrated ZEP520A solution in tetrahydrofuran, suggesting that initial reactions in the ZEP520A solid film that are induced only by direct ionization could be simulated via pulse radiolysis in specific solutions.
-ray irradiated organic thin film transistors based on perfluoropentacene with polyimide gate insulatorTakayanagi, Yutaro*; Ouchi, Hirokuni*; Duan, Z.*; Okukawa, Takanori*; Yanagi, Yuichiro*; Yoshida, Akira*; Taguchi, Mitsumasa; Hirao, Toshio; Nishioka, Yasushiro*
Journal of Photopolymer Science and Technology, 25(4), p.493 - 496, 2012/08
Times Cited Count：0 Percentile：0.01(Polymer Science)Organic thin film fields effect transistors are expected to be used in spacecrafts/satellites because they can realize large-size, mechanical flexibility, light weight and low-cost devices. N-channel field effect transistors with a Si/polyimide(PI)/perfluoropentacene/Au structure were fabricated, and irradiated with -ray from Co source. The changes of the drain current vs. source/drain voltage characteristics were measured after every 200 Gy in silicon Gy(Si) irradiations up to the total dose of 1200 Gy(Si). The drain current gradually increased up to the total dose of 1200 Gy(Si). The threshold voltage decreased up to 400 Gy(Si), and gradually recovered above 600 Gy(Si). The mobility was almost unchanged up to 1200 Gy(Si). Those behaviors were explained by accumulation of positive trapped charge within the gate insulator PI near the interface. Evidence for the accumulation of interface traps was hardly observed.
Takano, Katsuyoshi*; Asano, Atsushi*; Maeyoshi, Yuta*; Marui, Hiromi*; Omichi, Masaaki*; Saeki, Akinori*; Seki, Shu*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro; et al.
Journal of Photopolymer Science and Technology, 25(1), p.43 - 46, 2012/07
Times Cited Count：2 Percentile：6.54(Polymer Science)Okubo, Satoshi*; Takahashi, Tomohiro*; Takasawa, Yuya*; Gowa, Tomoko*; Sasaki, Takashi*; Nagasawa, Naotsugu; Tamada, Masao; Oshima, Akihiro*; Tagawa, Seiichi*; Washio, Masakazu*
Journal of Photopolymer Science and Technology, 23(3), p.393 - 397, 2010/11
Times Cited Count：4 Percentile：13.79(Polymer Science)Microfabrication of biodegradable polymers such as poly(butylene succinate-
-adipate) (PBSA) and poly(
-caprolactone) (PCL) were demonstrated using focused ion beam (FIB) with maskless direct etching. As the result, the micro structures of PBSA and PCL were obtained. The etching depth of both PBSA and PCL were increased with increasing FIB fluence, and the etching rates were estimated to be about 1.3 
10
m/(ions cm
) and 1.2 10 m/(ions cm), respectively. Moreover, very thin films of PBSA and PCL were made by spin-coating method. The thicknesses of the spin-coated samples were about 200 nm, and the surface roughness was less than 10 nm (RMS). The fine structures such as micro-gear of PBSA and PCL were obtained without solid debris. The line width of the fabricated structure was about 250 nm.
Gowa, Tomoko*; Takahashi, Tomohiro*; Oka, Toshitaka; Murakami, Takeshi*; Oshima, Akihiro*; Tagawa, Seiichi*; Washio, Masakazu*
Journal of Photopolymer Science and Technology, 23(3), p.399 - 404, 2010/08
Enomoto, Kazuyuki; Maekawa, Yasunari; Kono, Sachiko*; Iwasaki, Masakazu*; Narita, Tadashi*
Journal of Photopolymer Science and Technology, 23(2), p.217 - 224, 2010/06
Times Cited Count：0 Percentile：0.01(Polymer Science)Reversible color imaging on polymer films with spiropyran (SP-NO
) or diarylethene (DE) has been examined by electron-beam (EB) induced chromism combined with a photo- or thermal reverse reaction. Colorless SP-NO in a film transformed into red-colored merocyanine (MC-NO), which subsequently converted to the original SP-NO via thermal treatment. In contrast, a photo reverse reaction could be applied for EB-induced color imaging using DE in the polymer films, where the thermally stable colored close-form can be converted to the original colorless open-form via photoreaction. The color images of 200 nm L/S patterns were produced in the PMMA film containing SP-NO; the images could be faded upon the thermal treatment. It is noted that these reactions are the first example for reversible transformation of color imaging induced by EB radiation together with heat or light treatment.
ray irradiationTsukuda, Satoshi*; Asano, Atsushi*; Sugimoto, Masaki; Idesaki, Akira; Seki, Shu*; Tanaka, Shunichiro*
Journal of Photopolymer Science and Technology, 23(2), p.231 - 234, 2010/06
Times Cited Count：0 Percentile：0.01(Polymer Science)The nanowires based on polystyrene (PS) and polycarbosilane (PCS) were formed by 450 MeV Xe beam irradiation to their thin films. The nanowires, which formed by crosslinking reaction along the single ion path, can isolated by development procedures. This technique is sometimes called as single particle nanofabrication technique (SPNT). In this paper, tow step irradiation of ion beam and ray was carried out in order to control their radial sizes. The radial sizes of nanowires, based on PS and PCS were increased with the dose of ray. The change of radial sizes, which depended on the dose, was quantitatively measured, and we discussed in terms of radiation induced gel formation.
Park, J.*; Enomoto, Kazuyuki; Yamashita, Takashi*; Takagi, Yasuyuki*; Todaka, Katsunori*; Maekawa, Yasunari
Journal of Photopolymer Science and Technology, 22(3), p.285 - 287, 2009/08
Times Cited Count：0 Percentile：0.01(Polymer Science)Alicyclic Polyimide (A-PI) films were utilized as a substrate of radiation-induced polymerization to prepare PEM for fuel cells. We successfully prepared the A-PI- PEM by radiation-induced grafting of styrene into A-PI films and subsequent sulfonation. The obtained A-PI-PEM has higher ion conductivity and mechanical and thermal properties, compared with conventional PEM (Nafion). Furthermore, the long-lived intermediates in irradiated A-PI films were observed in the UV-VIS spectra. In comparison with the decay profile of ESR spectra of irradiated A-PI films, the initiation radicals (600, 420 nm) and radical anion (720 nm) can be characterized in terms of the graft polymerization mechanism of A-PI films.
Yamashita, Takashi*; Ogawa, Mutsuki*; Koshikawa, Hiroshi; Maekawa, Yasunari
Journal of Photopolymer Science and Technology, 20(5), p.739 - 742, 2007/00
Times Cited Count：6 Percentile：20.83(Polymer Science)Electron beam (EB) induced refractive index change of several polyimide films, which are one of the most thermally stable polymers. Introducing aliphatic amine into polyimide makes the polymer transparent and colorless in the visible wavelength region due to restriction of charge transfer, as well as increase in the sensitivity to EB induced reaction. One of the aliphatic poyimide, PI(HPMDA/mix-DCHM), prepared from cyclohexane tetracarboxylic anhydride and bis(4-aminocyclohexyl)methane, change the refractive index as large as 10
for both TE and TM modes. Chemical reaction during the EB irradiation was also determined as EB induced aromatization occurred.
Kato, Jun; Yuasa, Kanako; Matsushita, Harumi*; Maekawa, Yasunari; Enomoto, Kazuyuki; Ishii, Tatsuhito*; Ito, Kazuo*; Yamashita, Takashi*
Journal of Photopolymer Science and Technology, 19(1), p.105 - 110, 2006/00
Times Cited Count：2 Percentile：6.47(Polymer Science)The novel electron beam (EB)-induced color imaging system, consisting of polymer films with acid-responsive chromic molecules (chromic dyes) and EB-acid generators (EBAGs) was proposed. EB irradiation of the acid-chromic polymer films induced acid generation from EBAG, resulting in color formation of the acid-chromic molecules (protonated forms). Nanoscale color imaging on the acid- chromic polymer films was carried out using EB scanning direct drawing. Clear color imaging of 200 nm square and 100 nm line/space patterns could be observed with a dose of only 50 C cm. Furthermore, the large EB-induced refractive index change of these films (0.013 at 632.8 nm) was observed in both TE and TM modes by an m-line method, which is sufficient to create an optical circuit.
Yuasa, Kanako; Enomoto, Kazuyuki*; Maekawa, Yasunari; Kato, Jun*; Yamashita, Takashi*; Yoshida, Masaru
Journal of Photopolymer Science and Technology, 17(1), p.21 - 28, 2004/07
Times Cited Count：9 Percentile：31.07(Polymer Science)The electron beam (EB)-induced reactions of arylsulfonic acid esters, phenyl p-toluenesulfonate (1a), phenyl benzenesulfonate (1b), and phenyl 1-naphthalenesulfonate (1c), were examined in the balk state. The EB irradiation of 1a afforded the Fries rearrangement products, o- and p-hydroxyphenyl p-tolylsulfones (2a and 3a), phenol (5), and the oxidation product of 2a, o,p-dihydroxyphenyl p-tolylsulfone (4a), which has not been observed in photolysis. The irradiation of 1b, which is liquid at room temperature, gave Fries products, 5, and the oxidation product, o,p-dihydroxyphenyl phenylsulfone. On the other hand, the EB-induced reaction of 1c proceeded with the lowest reactivity through crystal to crystal transformation to afford Fries products and 5, but not oxidation product. The mechanistic study reveals that oxidation product 4a generated by the oxidation reaction of ortho-Fries product 2a but not para-isomer 3a with an active oxidant, which should result from the decomposition of 1a.
Enomoto, Kazuyuki*; Maekawa, Yasunari; Moon, S.; Shimoyama, Junji*; Goto, Kazuyuki*; Narita, Tadashi*; Yoshida, Masaru
Journal of Photopolymer Science and Technology, 17(1), p.41 - 44, 2004/06
Times Cited Count：2 Percentile：9.04(Polymer Science)The Electron beams (EB)-induced reactions of triphenylsulfonium methanesulfonate (1) in the crystalline state gave benzene-substituted product, biphenylsulfonium methanesulfonate (2), which has not been observed by either photolysis. In this paper, the EB-induced reactions of triphenylsulfonium salt derivatives, which possesses aromatic/aliphatic counter anions, have been examined. The anionic moiety of sulfonium salts has practically little effect on the formation of biphenyl salt 2 as well as the other products. The consumption rates of the sulfonium salts containing aromatic counter anions are somewhat smaller in a crystalline state and about two times larger than those of the salts with aliphatic counter anions. The greater decomposition rates of the sulfonium salts with aromatic counter anions than those of aliphatic counter anions in an amorphous state are elucidated by lower ionization potential of the salts with aromatic counter anions such as tosyl and naphthyl groups than those with aliphatic counter anions.
Moon, S.; Maekawa, Yasunari; Yoshida, Masaru
Journal of Photopolymer Science and Technology, 15(3), p.423 - 426, 2002/06
Times Cited Count：2 Percentile：9.44(Polymer Science)no abstracts in English
