Electron beam resist reactions mechanism

The progress of technology for the high-resolution fabrication of semiconductor and magnetic bubble devices has required sub-micron exposure techniques such as electron beam x-ray and deep UV. Although a number of papers have been published on electron beam resists, reaction mechanisms of electron resists are still largely unknown since few studies on reactive intermediates by means of direct measurements have been done in order to elucidate the reaction mechanisms. 

Basic and applied researches on charged particle and photon-induced reactions of polymers are surveyed. The basic parts are fundamentals of radiation effects on polymers and pulse radiolysis studies on polymers. The intermediate parts are a great diversity of radiation effects on polymers and reaction mechanisms of electron beam (EB) and x-ray resists. The applied parts are economic scale of utilization of radiation and industrial application of radiation to polymers. 

Onium salts have been widely used as an acid generator for photo-, EB, and x-ray resist. In addition, aromatic polymers such as novolak and polyhydroxystyrene have been often used as a base polymer for EB and x-ray resist. The reaction mechanisms in a typical resist system have been investigated by pulse radiolysis [43,52,77-88], SR exposure [79,80,83-85], and product analysis [88]. Figure 6 shows the acid-generation mechanisms induced by ionizing radiation in triphenylsulfonium triflate solution in acetonitrile. The yields of products from electron beam and KrF excimer laser irradiation of 10 mM triphenylsulfonium triflate solution in acetonitrile are shown in Fig. 7 to clarify the... 

T. Iwamoto, M. Akita, T. Kozawa, Y. Yamamoto, D. Werst, D.A. Trifunac, and D. Alexander, Radi ation and photochemistry of onium salts acid generators in chemically amplified resists, Proc. SPIE 3999, 204 213 (2000) A. Nakano, K. Okamoto, Y. Yamamoto, T. Kozawa, S. Tagawa, T. Kai, H. Nemoto, and T. Shimokawa, Deprotonation mechanism of poly(4 hydroxystyrene) and its deriva tives, Proc. SPIE 5753, 1034 1039 (2005) T. Kozawa, A. Saeki, and S. Tagawa, Modeling and simulation of chemically amplified electron beam, x ray, and EUV resist processes, J. Vac. Sci. Technol. B 22(6), 3522 3524 (2004) T. Kozawa, A. Saeki, A. Nakano, Y. Yoshida, and S. Tagawa, Relation between spatial resolution and reaction mechanism of chemically amplified resists for electron beam hthography, J. Vac. Sci. Technol. B 21(6), 3149 3152 (2003). 

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