A photochemical process for controlling block copolymer (BCP) domain orientation in an area selected manner is described. Polymers with photoswitching surface energy, used as interfacial underlayers adjoining the BCP layer, were synthesized with photoacid labile monomers. The interfacial polymers were designed to be either inherently neutral or preferential to poly(styrene-block-4-trimethylsilylstyrene). Through patternwise exposure to 193nm light and subsequent reaction with photogenerated acid, the wetting characteristics of the underlayer material can be switched from neutral to preferential (N2P) or preferential to neutral (P2N). Thermal annealing of the BCP confined between a patterned N2P or P2N substrate and a neutral top coat results in alternating areas of perpendicular and parallel BCP domains within the same film. If adapted in tandem with directed self-assembly, this approach could enable new routes to customizable patterns for advanced microelectronics and memory devices.

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We examined effects of doping with hydrophilic materials on micro-phase separation of polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA). As the hydrophilic materials, three organic acid compounds; butane -1,2,3,4- tetracarboxylic acid (BTA), cyclobutane -1,2,3,4- tetracarboxylic acid (CBTC), and sulfonyl-4,4'-diphenol (SNDP) were utilized in this experiment. By adding them to the PS-b-PMMA, it was found that they induced reducing phase-separation size. The doping of organic acid compounds into PS-b-PMMA decreased the phase separation size, while increasing doping PMMA homopolymer increased it. The PS-b-PMMA with low molecular weight PS 10.0 kg/mol -b- PMMA 10.0 kg/mol was utilized to examine the effect for phase-separation limit. By doping with 5 wt% of CBTC PS-b-PMMA showed lamellar structure with 8.2 nm half pitch. We considered that the doping organic acid compounds were a promising path for overcoming the phase-separation limit in PS-b-PMMA.

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This paper describes progress in the development of the recently proposed CHIPS flow for hexagonal hole array patterning. The CHIPS flow provides a versatile and low-cost route for patterning of dense hexagonal hole arrays which are specifically relevant for DRAM applications. In this paper, it is demonstrated that the required pre-pattern may be printed using single exposure 193nm immersion lithography. Furthermore, strategies for definition of the array edge are proposed and results on transferring the hexagonal hole array pattern into an inorganic underlayer are described.

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The thermodynamic mismatch of different segments in a block copolymer drives microphase separation, while their covalent bonds limit the phase separated domains to the nanometer scale. As a result, densely arranged high resolution patterns, the goal of lithography, form a thermodynamically preferred equilibrium state for block copolymers. For production new annealing methods are being explored to speed up and improve structure formation. Solvent vapor annealing is a powerful technique to control the ordering process and the morphology of block copolymers by selectively or non-selectively swelling polymers. In recent years high χ block copolymers are attracting more and more attention due to their potential to form small patterns. However, the ordering process of high χ block copolymer is kinetically slow, thus using solvent vapor or increased temperature to enhance the polymer chain mobility is a key to increase ordering rate. In this paper, we review recent work on using solvent annealing to control the morphology and report high speed laser annealing of high χ for lithographic applications.

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The present review summarizes our recent results regarding the synthesis and morphological characterization of sugar-based hybrid block copolymers (BCPs) consisting of maltoheptaose (MH) and poly(ε-caprolactone) (PCL). The AB-, AB₂-, AB₃-, ABA-, and A₂B-type BCPs, in which the A and B blocks are MH and PCL, respectively, were synthesized by combining the living polymerization and click reaction. The in-situ small angle X-ray scattering experiments revealed the formation of ordered microphase-separated structures with a sub-20 nm periodicity.

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The fabrication process of large-area self-assembled monolayers of gold nanoparticles was investigated, focusing on the effect of the solvent applying dip-coating system at fast rates (mm/sec). The uniformity of the particle array formed on the substrate was improved by polymer coating on the nanoparticle surface that prevents movement of particles during the drying process. We have also examined the effects of solvent in suspension on formation of nanoparticle films. The uniformity of films on the substrate was improved by selecting methyl ethyl ketone (MEK) as a solvent. In addition, it was found that the solvent annealing with MEK vapor promotes rearrangement of nanoparticle alignment in the films. Self-assembling performances of nanoparticles were also demonstrated by applying topographical pattern.

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We have demonstrated the synthesis and morphology chracterization of fluorine-containing PMAPOSS based block copolymers, PMAPOSS-b-PTFEMAs. The resulting block copolymers show the formation of lamellar structures in a bulk. Upon thermal annealing, the vertical oriented lamellar structures are formed by the surface segregation and microphase separation in the thin films on a variety of substrates. Very short annealing time only for one minute under an air atmosphere is also benefit for manufcturing processes. The excellent self-assembling characetristics, good etch selectivity between the blocks, and vertical orientation ability of lamellar structures make the PMAPOSS-b-PTFEMAs an ideal candidate for block copolymer lithography.

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Reduction of impurities such as gels and metals is one of the critical requirements in chemistries used in directed self assembly lithography (DSAL). In this study, we focused on elucidating the forms of the gels and metals in block copolymer (BCP) solution to effectively reduce these impurities. As a result, particles or gels, and ions are suggested as forms of metals. To reduce these multiple forms of metals, multistep filtrations such as repetitive filtration of single filter material and combination of different type of filters are conducted. As a result, more than 99.99% of Li and more than 99.9% of Al are reduced with a combination of Nylon 6,6 10 nm filtration and ion exchange filtration. The order of the filtration steps does not impact the removal efficiency. The results should contribute realizing DSAL in semiconductor device fabrication.

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To extend the scaling beyond the most widely used block copolymer (BCP), poly(styrene)-block-poly(methyl methacrylate) (PS-b-PMMA), a new organic high-χ BCP based was developed. Polystyrene-b-polytrimethylene carbonate (PS-b-PTMC) BCP was synthesized using ring opening polymerization (ROP) of trimethylene carbonate from hydroxy-functional polystyrene (PS-OH) with diazabicyclo[5.4.0]undec-7-ene (DBU) as the base catalyst. The resulting BCP was characterized by ¹H nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) to confirm the complete chain extension of the polystyrene macroinitiator. For the DBU catalyzed BCP, the GPC trace revealed a trimodal distribution indicating the presence of coupling product and homo-PTMC impurity. Using purification techniques, homo-PTMC impurity was isolated to afford purified BCP. Thin-film morphologies of the non-purified and the purified BCPs on poly(methyl methacrylate) (PMMA) coated substrates followed by short thermal annealing were characterized using atomic force microscopy (AFM) analysis. The non-purified BCP showed island morphology with a step-height of 17 nm whereas the purified PS-b-PTMC showed a flat film with parallel cylinders of 16.4 nm pitch row-to-row distance. The ability for the PS-b-PTMC to self-assemble below 20-nm pitch resolution confirms the high interaction parameter, χ, between the PS and PTMC blocks and is a promising candidate as a high-χ BCP for directed self-assembly (DSA) application.

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Previously, we demonstrated an all dry, selective laser ablation development in methyl acetoxy calixarene (MAC6) which produced high resolution (15-25 nm half-pitch), high aspect ratio features not achievable with wet development. In this paper, we investigate the selective laser ablation process as a means to create a block copolymer derived lithographic pattern through the selective removal of one block. Two block copolymer systems were investigated PS-b-PHOST, and P2VP-b-PS-b-P2VP. The selective laser ablations process on block copolymers offers an alternative to plasma etching when plasma etching is not effective.

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The energy of photons used for high-volume production of semiconductor devices will enter the energy range of ionizing radiation upon the use of extreme ultraviolet (EUV) radiation. In the energy range of ionizing radiation, thermalized electrons play the major role in the sensitization of acid generators in the chemically amplified resists, the standard resist for high-volume production of semiconductor devices. In this study, the effects of thermalization distance on the line edge roughness (LER) in the sub-10 nm fabrication using EUV lithography were investigated on the basis of the sensitization mechanisms of chemically amplified EUV resists. The optimum thermalization distance in terms of the trade-off relationships between resolution, LER, and sensitivity decreased with the half-pitch of line-and-space patterns. The optimum thermalization distance decreased to less than 2 nm at 9 nm half-pitch and further decreased to less than 1 nm at 5 nm half-pitch.

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Pattern formation in electron beam lithography (EBL) is investigated with molecular dynamics simulations. The electron exposure and development process are modeled by polymer chain scission and polymer segment removal from the resist, respectively. The line edge roughness of a sub-10-nm resist pattern is analyzed with the simulations. The proximity effect in EBL is also investigated. The effects of resist molecular size, secondary electron generation, and the substrate material are discussed.

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We have investigated the generation mechanisms of pattern defects in directed self-assembly (DSA) lithography using a simulation method based on self-consistent field theory (SCFT). The SCFT simulation results could reproduce grid defects, which are considered to be a kind of hexagonally perforated lamellar (HPL) metastable phase, as one of the characteristic pattern defects in the coordinated line epitaxy (COOL) DSA lithography process using polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA). We found that the grid defects were susceptible to be generated when a neutral layer was weakly attractive to PMMA block. Investigation of the PMMA segment node density profiles in the grid defects revealed that the terminal segments of the PMMA blocks indicated higher node density immediately above the neutral layer. These simulation results imply that the generation mechanism of the grid defects is strongly related with the interaction between the neutral layer bottom wafer and the terminal segment of the PMMA block.

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We use three-dimensional self-consistent field theory (SCFT) to study the self-assembly of cylinder forming diblock copolymers confined in elongated templates. This situation arises in contact holes where the goal is to produce a contact hole with reduced dimensions as well as with narrowed pitch of the center-to-center distance of cylinders. In this study, we focus on systems where two minor-block cylinders form in inside of the elongated templates. A defective bridge structure is extensively studied in this work and we evaluate the defect in various wall affinities such as “all PMMA-attractive templates”, “all neutral templates” and “PMMA-attractive sidewall with the neutral substrate”. According to our SCFT simulations, the defect formation energy of the bridge is typically above 20 kT, or fewer than 2 defects per billion in the “all neutral” template and “PMMA-attractive sidewall with the neutral substrate”, while the defect preferably forms in the “all PMMA attractive” template.

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Organic ionic compounds, such as photo-acid generators (PAGs) and photo-decomposable quenchers (PDQs), are solvated in organic solvents. During this process, organic ionic comounds can be solvated only in an associated salt form or both in an associated salt form and a dissociated ionic form. In order to understand this behavior, we carried out (1) the binding energy calculation of photo-acid generator (see, Figure 1) in various solvents, (2) the Job plots with ¹H NMR spectroscopy for detecting the dissociated anions of organic ionic compounds by a bidentated hydrogen bonding, and (3) GCIB-SIMS analysis to monitor the distribution of cations and anions along the depth of coated photoresist layer. Based on the computational and experimental results, we propose that organic ionic compounds are solvated in both an associated salt form and a dissociated ionic form in equilibrium state resulting in ion exchange of cations and anions in mixed organic ionic compounds.

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Gold nanoparticles have been becoming attractive metals in biomedical applications. The unique optical, chemical, and biological properties of gold nanoparticles have supported them for clinical interest in several applications including drug and gene delivery. Gold nanorods have strong absorption bands in the near-infrared region, in which light penetrates deeply into tissues. Hence, gold nanorods are expected to act not only as on-demand thermal converters for photothermal therapy but also as controllers of a drug-release system responding to irradiation by near-infrared light. These attributes can be promoted to provide an effective and selective platform for a targeted intracellular release of some substance. Here we review recent advances in the use of gold nanorods in drug and gene delivery systems.

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The surface of NaYF₄ NPs were successfully modified via stepwise modification procedure, ligand exchange and electrostatic adsorption reactions. The obtained PEGylated NaYF₄ NPs showed high dispersion stability under physiological conditions. Furthermore, the PEGylated NaYF₄ NPs displayed minimal cell cytotoxicity in the range of general criteria of RED-CNPs concentration for live cell imaging. Therefore, the obtained PEGylated NaYF₄ NPs is a promising candidate of NIR imaging probes.

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The PMBN surface is alternative to cell membranes or lipid layers for revealing activation dynamics of human CRP as well as for quantifying the systemic CRP level in the range from normal to acute-phase conditions. Featuring cutting edge material engineering, the biomimetic interface establishes a new paradigm for molecular science that measure dynamic changes of biomolecular activity in the local tissue microenvironments of inflammation and infection at any time.

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The improved catalytic activity of enzymes is required in various fields. Enzymes have conventionally been improved by the screening of bacteria possessing mutant enzymes. However, the screening conditions are limited since screening requires the growth of bacteria. Here, we report the development of a protein microarray for the analysis of enzymatic activity. A his-tagged enzyme is synthesized in situ and immobilized on the microarray, which is composed of microreactors with a diameter and depth of 4 μm and a density of 1.0 x 10⁶ reactors/cm². β-glucosidase, synthesized in situ using a cell-free synthesis system, was immobilized on the microreactor array chip and its catalytic activity was observed. This enzyme-immobilized microarray is expected to enable the rapid and quantitative screening of enzymes.

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A microfluidic-chip-based analysis platform specially tuned for characterizing individual nanobio-particles has been developed. Using this platform, both artificial nanobioparticles (polyion complex vesicles) and cell-secreted exosomes with diameter down to 50 nm can be observed. The zeta potential distribution of the exosomes was obtained by measuring the zeta potential of individual exosomes. Since the number of surface molecules on nanobioparticles can be estimated by applying a particle immunoelectrophoresis method, this platform is promising for obtaining profiles of heterogeneous nanobioparticles including nanoDDS carriers and exosomes.

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