The Photopolymer Science and Technology Award No.160010, the Outstanding Achievement Award 2016, was presented to Takumi Ueno (Shinshu University) for his outstanding achievements in photopolymer science and technology, "Development of new advanced photosensitive materials for microelectronics".

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The Photopolymer Science and Technology Award No. 160100, the Best Paper Award 2016, was presented to Tatsuhiko Yajima, Wenfeng Hai, Tei Hi and Keita Shimizu (Department of Applied Chemistry, Graduate School of Engineering, Saitama Institute of Technology) for their outstanding contribution published in Journal of Photopolymer Science and Technology, 28, (2015) 479-483, entitled "Preparation of a Super Hydrophilic Polytetrafluoroethylene Surface Using a Gaseous Ammonia-Water Low-Temperature Plasma".

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The Photopolymer Science and Technology Award No. 160200, the Best Paper Award 2016, was presented to Hiroki Takano^a, Lei Wang^a, Yuki Tanaka^a, Rina Maeda^a, Naoko Kihara^b, Yuriko Seino^b, Hironobu Sato^b, Yoshiaki Kawamonzen^b, Ken Miyagi^b, Shinya Minegishi^b, Tsukasa Azuma^b, Christopher K. Ober^c, and Teruaki Hayakawa^a (^aDepartment of Organic and Polymeric Materials, Tokyo Institute of Technology, ^bEUVL Infrastructure Development Center, Inc, ^cMaterials Science & Engineering, Cornell University) for their outstanding contribution published in Journal of Photopolymer Science and Technology, 28, (2015) 649-652, entitled "Vertical Oriented Lamellar Formation of Fluorine- and Silicon-containing Block Copolymers without Neutral Layers".

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Formation of two- and three-dimensional micro architectures with chemical functions was verified by photo-vapor phase assisted surface polymerization (VASP) of functional monomer vapors combined with an auto-drawing system manipulated by prescribed programs. The surface modification by the photo-VASP of styrene vapor progressed rapidly, and a fine lines-pattern of photo-mask was transcribed as the corresponding polymer accumulations on poly(methyl methacrylate) (PMMA) substrate surfaces. Substrate surface modified by photo-VASP of acrylic acid showed reversible changes in hydrophilic/hydrophobic properties according to repeating external chemical stimuli. The successive auto-drawing by photo-VASP of three kinds of monomer vapors was examined under spot illumination from a fine optical fiber on an X-Y stage manipulated by a prescribed program, resulting in the production of a pre-designed functional structure by successful accumulations of corresponding polymers on the substrate surface.

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In this paper, 8-hydroxyquinoline aluminum/polypyrrole (Alq₃/PPy) core-shell composites were prepared via in situ chemical oxidative polymerization with ammonium persulfate (APS) as oxidizer and hydrochloric acid (HCl) as dopant. The structure and properties of PPy, Alq3 and Alq3/PPy composites have been studied by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The electrical conductivities of Alq₃/PPy composites were evaluated using ohmmeter. It is found that the Alq3/PPy composites are successfully synthesized via in situ oxidative polymerization. The results of thermogravimetric analysis showed that relatively good thermal stability of Alq₃/PPy composites. Furthermore, the probable formation mechanism of Alq₃/PPy core-shell structure composites was also proposed on the basis of the experimental results.

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A novel fluoro-containing tetralin dianhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-6-fluoro-1-naphthalene succinic dianhydride (FTDA) was successfully prepared via a cost-effective route with maleic anhydride and p-fluorostyrene as the starting materials. A series of semi-alicyclic polyimides (PIs) have been synthesized from FTDA and aromatic diamines, including 4,4'-oxydianiline (ODA) for PI-a, 1,4-bis(4-aminophenoxy)benzene (APB) for PI-b, 2,2'-bis[(4-aminophenoxy)phenyl]propane (BAPP) for PI-c, and 2,2'-bis[(4-aminophenoxy)- phenyl]hexafluoropropane (BDAF) for PI-d via a one-step high-temperature imidization procedure. The derived PI resins are easily soluble in polar aprotic solvents, such as N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAc). Flexible and tough PI films were cast from their solutions in NMP at a solid content of 15 wt%. The prepared PI films exhibited good optical transparency in the visible light region with the transmittance higher than 80% at the wavelength of 450 nm. In addition, the PI films exhibited good thermal stability with the 5% weight loss temperatures >402 ^oC and glass transition temperatures >230 ^oC.

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Pattern fidelity in hot embossing is influenced to a large extent by defects induced with mold releasing from polymer resist. It is necessary to investigate contact properties of interface between the mold and the polymer resist during demolding process. In this paper, influences of friction coefficient and cohesion on deformation in the polymer resist during the demolding are studied via finite element method. An optimization finite element model with nickel mold/polymer resist structure was constructed, considering both mechanical properties of the polymer resist and optimal element number. Simulation results show that there exist the optimum friction coefficient and the optimum cohesion allowing the deformation of the polymer resist to be minimal. These optimum contact properties can be applied in guiding selections of material and improving quality of embossed patterns.

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Reduction of resist filling time was investigated with the aim of improving UV-nanoimprint lithography (UV-NIL) throughput.　A novel low volatility, low viscosity resist was developed to enable ink-jetting with minute resist droplets and imprinting under reduced air atmosphere. Direct observation of resist spreading showed that the resist filling process is composed of three steps: A) capillary bridge formation, B) resist spreading, and C) air bubble dissolution. Resist filling time was drastically decreased by changing the atmosphere from helium to a reduced air atmosphere of 0.02MPa. A comparison of 0.7pl and 6pl resist droplets showed that reducing resist droplet size while increasing area density also reduces resist filling time. Improved bubble dissolution speed is thought to result from imprinting under reduced air atmosphere. Moreover, ink-jetting smaller size resist droplets with higher density is thought to have an effect on reducing the time of each of the three steps, particularly bubble dissolution time. Combining dispensing-NIL with imprinting in vacuum is expected to improve UV-NIL throughput.

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We developed replica film mold made of specific resin. Durability and transfer properties against transcription material of both the film mold and common PDMS were evaluated. Furthermore, to extend applications of film mold, micro-nano mixed structure was fabricated in film mold as we reported [3]. Finally, the film mold was applied to the roll-to-roll (R2R) UV nanoimprinting process, because high throughput is essential to achieve the mass production.

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There are several options for sub-10nm fabrication such as extreme ultra violet (EUV) lithography, directed self-assembly (DSA), and ArF multiple patterning. For further extension of ArF lithography, one of the key challenges is cost effectiveness. In this paper, a new double patterning method - pattern split process (PSP), which is based on dual tone development is demonstrated. Different from conventional DTD, additional acid and base materials were used in this process to gain high deprotection contrast. By PSP, double pitch frequency pattern which has improved roughness was successfully obtained. Also other basic parameter such as focus margin, wafer uniformity and resolution are reported.

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Metal oxide or metal nitride films are used as hard mask materials in the semiconductor lithography processes due to their excellent etch resistances against the plasma etches. Chemical vapor deposition (CVD) or atomic layer deposition (ALD) techniques are usually used to deposit the metal containing materials on substrates or underlying films, which uses specialized equipment and can lead to high cost-of-ownership and low throughput. The present paper describes formation and functional properties of novel metal oxide hard masks by simple solution spin coating process. These stable metal oxide formulations containing significant amount of Ti, W, Hf, Zr and Al possess good etch selectivity and therefore good pattern transfer capability. The metal oxide films can be removed by commonly used wet chemicals in the fab environment such as TMAH developer, solvents or other oxidizing agents. The hard mask material absorbs DUV wavelengths and hence can be used as a spin-on inorganic or hybrid antireflective coating to control substrate reflectivity. Some metal hard masks are also developed for via or trench filling applications for electronic devices as high K materials. The research demonstrated that these metal oxide hard masks are compatible with litho track and etch processing without concern of metal contamination. They can, therefore be integrated as replacements of CVD or ALD metal, metal oxide, metal nitride or spin-on silicon-containing hard mask films in 193 nm or EUV processes. This paper discusses coating, optical, filling, etch and wet removal properties the spin-on metal oxide formulations. In addition, a new potential application in self-aligned quadruple patterning cut process for advanced technology nodes is also described.

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ArF lithography is still major process to develop N7/N5 devices. Especially in resist materials, DOF, roughness and CD uniformity are the biggest key parameters in fine pitches. To improve these issues, we newly propose to apply Dry Development Rinse Process (DDRP) & Materials (DDRM) as the ArF extension approach. In EUV lithography, DDRP is already one of the approaches to achieve high resolution. However, the performance of DDRP for ArF lithography was never demonstrated in detail. In this paper, we especially focus to improve DOF, CD uniformity and roughness by applying DDRP for ArF generation. Finally we succeeded to enhance every parameter at the same time by controlling DDRM etching condition. This new DDRP technology can be the promising approach for ArF extension stages in N7/N5 and beyond.

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Negative tone imaging (NTI) process is a method for obtaining a negative-tone reversal pattern by developing with an organic solvent. As NTI process can break-through the resolution limit of a conventional positive tone development (PTD) process at specific pattern such as trenches and contact holes, it has been applied for a mass production in 20nm and 14nm nodes devices. In NTI system, because a developer is changed from a hydrophilic aqueous solution to a hydrophobic organic solvent, it is possible to review the common resist stack which is optimized for a PTD process. In this paper, we examined the possibility of a bi-layer process using a Si-containing NTI resist. Etching selectivity between the Si-NTI resist and a SOC improved by raising Si-content of the Si-NTI resist, but resolution deteriorates as a trade-off. By suppressing swelling behavior of the Si-NTI resist with a polymer structure control, we overcame this trade-off. As a result, in sub-90 nm pitch L/S and CH patterns, the resolution of the Si-NTI resist achieved comparable level to a conventional NTI resist. In addition, SOC etching was successfully carried out by using the Si-NTI resist pattern as an etching hard mask.

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ZEP resist patterns, which have been widely used in nanofabrication in research laboratories, are shrunk during an SEM observation. This shrinkage effect makes it challenging to accurately determine their original sizes. In this work, the shrinkage effect of electron beams on ZEP resist line-space patterns was explored by AFM measurement at different exposure doses. The results shown that the shrinkage happened at doses as low as 0.05 mC/cm², and dramatically increased before being saturated at high doses of 16-24 mC/cm² (at 30 keV). For patterns with the same height, a smaller pattern tended to undergo a bigger shrinkage. The heights of patterns also had a great impact on their shrinkages. In the saturation region at high does, the patterns were unchanged in isopropyl alcohol developer. The insolubility of the patterns suggested that the resist had changed to a negative tone, where the number of crosslinking sites of the resist was high, and caused the saturation of shrinkage. A new method for estimating of the original size was also introduced using a combination of SEM, EB exposure, and AFM.

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The use of photoinduced processes enabling polymer chemists to synthesize tailored novel macromolecular architectures has recently been revitalized. In this presentation, new photochemical approaches, mainly developed in the authors’ laboratory, were highlighted. It was shown that many homogenous and heterogeneous photoinitiators including structurally modified polymers, nano and porous materials are capable of initiating conventional free radical and cationic polymerizations under UV and visible light. Photoinduced Atom Transfer Radical Polymerization (ATRP) and Copper Catalyzed Azide Alkyne Cycloaddition (CuAAC) click processes, both based on photoredox reactions of copper catalysts, have been discussed. Their independent and combined use by sequential or in situ manner for macromolecular synthesis is also demonstrated.

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We investigated the formulations of acrylates which were applicable to UV-C LED lamps. The mixtures of acrylate monomers and photoinitiators were placed on silicon wafer or sandwiched between a silicon plate and a CaF₂ plate to obtain sample films. The films were irradiated by UV-C LED lamps which emit 265, 285, and 300 nm-lights. The effect of initiators, irradiation wavelength, and atmosphere on the conversion of the acryl unit was investigated using FT-IR spectroscopy. We found that the photoinitiator O-benzoyl 2,3-butanedione monooxime was the most effective photoinitiator for 265-nm light. The effect of atmosphere in the system was clearly observed.

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Inorganic silane oligomer based on tetraethoxysilane was synthesized via sol-gel under acidic condition. UV curable organic-inorganic hybrid coatings were then prepared using the synthesized inorganic oligomers and tetraethylene glycol diacrylate. The effect of organic/inorganic content ratio on gelation and shrinkage of samples was investigated by photorheometry. It was revealed that incorporating higher amount of inorganic component in the samples improves the system mobility and postpones gelation. It also reduces the final film shrinkage that is stemmed from photopolymerization induced phase separation.

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This contribution summarizes recent progress in the field of near-infrared (NIR) initiated photopolymerization. The photoinitiator system consists of a cyanine as sensitizer (Sens) and an iodonium salt with distinct structural pattern of both the cation and anion as radical initiator. Both, photonic and thermal events are discussed as the main source for formation of initiating species. Electron transfer between the excited state of Sens (Sens*) and the iodonium salt can be seen as the main source for formation of initiating species such as radicals and protons/electrophiles. Furthermore, the ion mobility as probed by the electric conductivity possesses a major function to tune the reactivity of the photopolymer system. The reactivity of these systems was studied in different applications such as Computer to Plate (CtP), LED curing, photonic baking, and curing of powder coatings with NIR lasers exhibiting line shape focus.

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(Meth)acrylated methyl oleates substituted with a hydroxy or bromo group were synthesized starting from oleic acid. The latter belongs to materials derived from renewable resources. These new hydroxy or bromo substituted methacrylated methyl oleates possess a higher reactivity compared to lauryl methacrylate in photoinitiated polymerization using Ivocerin as photoinitiator. Hydroxy acrylated methyl oleate is more efficient in photopolymerization compared to bromo acrylated methyl oleate and lauryl acrylate in the presence of both nitrogen and air. Furthermore, the (meth)acrylated methyl oleates are interesting in applications for coatings because the design of the monomers opens a certain oxygen barrier function.

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In this study, the photopolymerization kinetics of bifunctional acrylic monomers having different chain lengths, such as 1,4-bis(acryloyloxy)butane, 1,6-bis(acryloyloxy)hexane, and 1,10-bis(acryloyloxy)decane, was investigated by real-time Fourier transform infrared (FTIR) spectroscopy, using Irgacure 184 (1 wt%) as the photoinitiator. Dark polymerization analysis was employed for measuring the kinetic constants for propagation and termination. Plots of kinetic constants for propagation against double-bond conversion showed a plateau, suggesting that the reaction rate is controlled at low conversion, and with increasing conversion, the reaction rate decreases as the diffusion rate of the monomer controls propagation. At low conversion, as compared to the reaction for a monomer having a long chain length, the propagation reaction for a monomer with a short chain length switched to a diffusion-rate controlled propagation reaction. The results suggested that short chain length monomers form a dense cross-linking network, which hinders the diffusion of the monomer, and the kinetic constants decrease at low conversion. The results obtained from the plot of kinetic chain length versus conversion indicated that at a maximum kinetic chain length of up to 10⁶, the reaction switches to the diffusion-rate controlled propagation of each monomer.

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We report the serial photo-induced polymerization and degradation behavior of formulations without solvent in order to observe more remarkable changes, and compare them to that of formulation containing as a non-degradable crosslinker.

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In this paper, we focus on novel types of dendritic polynorbornenes because norbornene is regarded as one of the most promising ene units in thiol-ene chemistry because of its enhanced ability to activate carbon radicals due to the distorted structures. We describe here the effect of the norbornene units located at the outermost position of the dendrimers on the photosensitivity of the thiol-ene UV curable materials.

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An inverse opal film was layered to a photodeformable film, and its photoresponsive behavior was investigated. This bilayer films composed of colorless photonic crystal using inverse opal structures and colored photoresponsive layers with azobenzene-containing CLCP.

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The direct and reversible solid-liquid phase transitions by photochromic reactions at constant temperature are of interest because of potential applications in reusable adhesives, photoresists and so on. We report photoinduced solid-liquid phase transitions in rod-shaped azobenzenes, possessing a methyl group at the 3-position and alkoxy groups with different chain length (Cn = 1-18) at the 4- and 4'-positions. Thermal property, photochemical property, and adhesive properties were investigated. We found that the azobenzenes with alkyl chain length of 6-10 showed relatively fast photoinduced solid-liquid phase transition than that with shorter (Cn = 1-5) and longer (Cn = 11-18) ones. Tensile shear strength were measured by using these azobenzenes as photoresponsive adhesives. Irradiation with UV light (365 nm) induced the phase transition to the liquid phase and the adhesion strength values decreased to almost zero. Then the irradiation with visible light (450 nm) recovered the adhesion strength.

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