Polymerization of (4-(methacryloyloxy)phenyl)dimethylsulfoniumtriflate (MAPDST), as a key monomer containing the radiation sensitive sulfonium functionality, with various other monomers such as methyl methacrylate (MMA), 4-carboxy styrene (STYCOOH), N-vinyl carbazole (NVK) in different molar ratios via free-radical polymerization method is described. This methodology led to the development of a small chemical library of six different radiation sensitive polymers for lithography applications. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy identified the reaction products as MAPDST homopolymer and MAPDST-MMA, MAPDST-STYCOOH, MAPDST-NVK copolymers. Molecular weights were obtained from gel permeation chromatography and the decomposition temperature (Td) values were determined using thermogravimetric analysis (TGA). The effect of extreme ultraviolet (EUV) irradiation on a thin poly(MAPDST) film was investigated using monochromatic synchrotron excitation. These new polymeric materials were also exposed to electron-beam lithography (EBL) and extreme ultraviolet lithography (EUVL) to achieve 20-nm line patterns.

Abstract. Although extreme ultraviolet (EUV) lithography is being considered as one of the most promising nextgeneration lithography techniques for patterning sub-20 nm features, the development of suitable EUV resists remains one of the main challenges confronting the semiconductor industry. The goal is to achieve sub-20 nm line patterns having low line edge roughness (LER) of <1.8 nm and a sensitivity of 5 to 20 mJ∕cm 2 . The present work demonstrates the lithographic performance of two nonchemically amplified (n-CARs) negative photoresists, MAPDST homopolymer and MAPDST-MMA copolymer, prepared from suitable monomers containing the radiation sensitive sulfonium functionality. Investigations into the effect of several process parameters are reported. These include spinning conditions to obtain film thicknesses <50 nm, baking regimes, exposure conditions, and the resulting surface topographies. The effect of these protocols on sensitivity, contrast, and resolution has been assessed for the optimization of 20 nm features and the corresponding LER/line width roughness. These n-CARs have also been found to possess high etch resistance. The etch durability of MAPDST homopolymer and MAPDST-MMA copolymer (under SF 6 plasma chemistry) with respect to the silicon substrate are 7.2∶1 and 8.3∶1, respectively. This methodical investigation will provide guidance in designing new resist materials with improved efficiency for EUVL through polymer microstructure engineering.

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New Schiff base 2-[(4-Methyl-2-oxo-2H-chromen-7-yl)oxy]-N'-(substitutedmethylene)aceto hydrazides (4a-p) were synthesized by the condensation of aryl/hetero aromatic aldehydes with 2-[(4-methyl-2-oxo-2H-chromen-7-yl)oxy]acetohydrazide under conventional and microwave conditions and characterized through IR, 1 H NMR and Mass spectral data. The synthesized compounds have been screened for antimicrobial activity.

Two new polyoxometalate (POM)-based hybrid monomers (Bu4 N)5 (H)[P2 V3 W15 O59 {(OCH2 )3 CNHCO(CH3 )CCH2 }] (2) and (S(CH3 )2 C6 H4 OCOC(CH3 )=CH2 )6 [PV  2Mo10 O40 ] (5) were developed by grafting polymerizable organic units covalently or electrostatically onto Wells-Dawson and Keggin-type clusters and were characterized by analytical and spectroscopic techniques including ESI-MS and/or single-crystal X-ray diffraction analyses. Radical initiated polymerization of 2 and 5 with organic monomers (methacryloyloxy)phenyldimethylsulfonium triflate (MAPDST) and/or methylmethacrylate (MMA) yielded a new series of POM/polymer hybrids that were characterized by (1) H, (31) P NMR and IR spectroscopic techniques, gel-permeation chromatography as well as thermal analyses. Preliminary tests were conducted on these POM/polymer hybrids to evaluate their properties as photoresists using electron beam (E-beam)/extreme ultraviolet (EUV) lithographic techniques. It was observed that the POM/polymer hybrid of 2 with MAPDST exhibited improved sensitivity under EUV lithographic conditions in comparison to the MAPDST homopolymer resist possibly due to the efficient photon harvesting by the POM clusters from the EUV source.