Selective Fragmentation of Radiation-Sensitive Novel Polymeric Resist Materials by Inner-Shell Irradiation
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- 作者：Gabriela Ramos Chagas ; Vardhineedi Sri Venkata Satyanarayana ; Felipe Kessler ; Guilherme Kretzmann Belmonte ; Kenneth E. Gonsalves ; Daniel Eduardo Weibel
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2015
- 出版时间：August 5, 2015
- 年：2015
- 卷：7
- 期：30
- 页码：16348-16356
- 全文大小：466K
- ISSN：1944-8252
文摘
Two key concepts in extreme ultraviolet lithography (EUVL) are important for it to be a candidate for the mass production of future integrated circuits: the polymer formulation and the photofragmentation process. In this work, both concepts were carefully studied. The design and synthesis of radiation鈥搒ensitive organic polymeric materials based on the inclusion of a radiation-sensitive tetrahydrothiophenium functional group are outlined. A 1-(4-methacryloyoxy)naphthalene-1-yl)tetrahydro-1H-thiophenium trifluoromethanesulfonate (MANTMS) monomer containing the tetrahydrothiophenium group undergoes homo- and copolymerizations using free-radical polymerization with a 2,2鈥?azobis(isobutyronitrile) initiator. The surface photodegradation and oxidation of these novel polymeric materials were investigated using highly monochromatized soft X-rays from synchrotron radiation at the carbon K-edge excitation region. An efficient functionalization was observed when the excitation energy was tuned to C 1s 鈫?蟺*C鈺怌. A high rate of defluorination and a loss of sulfonated groups as a result of an increase in the irradiation time for the MANTMS homopolymer thin films were mainly observed under the 蟺*C鈺怌 excitation of the naphthyl functional groups. On the contrary, excitation similar to C 1s 鈫?蟺*C鈺怬 or C 1s 鈫?蟽*C鈥揊 did not produce important degradation, showing a highly selective process of bond breaking. Additionally, the presence of methyl methacrylate copolymer in the original MANTMS yielded a much higher degree of stability against inner-shell radiation damage. Our results highlight the importance of choosing the right polymer formulation and excitation energy to produce a sensitive material for EUVL without using the concept of chemical amplification.