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Chemical mechanical polishing/planarization (CMP) slurry contains mainly abrasive grains (primary particles) with few aggregations (secondary particles). Measuring the particle size distribution (PSD) of CMP slurry is crucial for improving the productivity of the CMP process. For the quality management of CMP slurry, it is necessary to evaluate both the sizes and quantities of both the primary and secondary particles. Conventional PSD analysis methods, except for image analysis, face challenges in identifying primary and secondary particles for PSD measurements. For image analysis, the particles must be transferred from a suspension to a substrate using the conventional sampling method; however, this creates aggregates, resulting in a change in the PSD of the particles on the substrate compared to that in suspension under poly-dispersed conditions. Thus, this study proposed a novel particle sizing method using nanoparticle chip (NPC) to assist in the image analysis of the PSD. The NPC can pick up a single particle in a small volume droplet to avoid aggregation and maintain the poly-dispersed condition of the particles in suspension. The primary and secondary particles can be identified using scanning electron microscope (SEM) or atomic force microscope (AFM), and the PSD can be evaluated by measuring the area and height of the particles. Further, the quantities of both the primary and secondary particles can be counted from the substrate. This study presented a comparison of the diameter measurements using NPC and the conventional method. The results show that the NPC identified the primary and secondary particles and decreased the measurement error of the particle diameters. Consequently, the NPC proves to be superior to the conventional method for use in the PSD analysis of CMP slurry. • Nanoparticle chip (NPC) sizing for CMP slurry particle size distribution (PSD). • NPC avoids particle aggregation, maintains PSD in poly-dispersed suspension. • Primary and secondary particles separated to lower equivalent height diameter error. • PSD of primary particles and number of secondary particles measured using NPC. [ABSTRACT FROM AUTHOR]

Particle size distribution (PSD) analysis for nanoparticle is important for quality management of CMP slurry, that used in chemical mechanical polishing (CMP) process. CMP slurry contains poly-dispersed particles, which consist of size-different primary particles and secondary particles in suspension. It is difficult to measure PSD for poly-dispersed particle using Dynamic Light Scattering, which is one of a typical method to evaluate PSD for mono-dispersed particles. The image analysis is also employed for PSD analysis. For image analysis, it needs to transfer the particles from suspension to a substrate before measurement. In this procedure, some particles aggregate with surrounding particles. It causes the difference between the PSD for dispersed particles in suspension and the PSD for observed particle using image analysis. In addition, concentration measurement is important for quality management of CMP slurry. Mass concentration is used in concentration evaluation for CMP slurry. However, it is difficult to identify the molar concentration for multi-modal particles, respectively. In this study, we suggested a method to define molar concentration spectra to express both a modal diameter and molar concentration for multi-modal nanoparticles to evaluate the CMP slurry. In order to measure the molar concentration spectra, we suggested a novel particle sizing method using nanoparticle chip (NPC) to measure number-weighted mean particle diameter, a variance of diameters, and molar concentration for every spectrum. Nanoparticles grid on a substrate to maintain the poly-dispersed condition in suspension to process NPC. NPC can assist the image analysis process to measure the PSD of particles in suspension. The number of particles, that aligned on the substrate, can be counted to measure the molar concentration. In this paper, a fundamental experiment was performed to investigate the feasibility of molar concentration spectra measurement. It is confirmed the molar concentration spectra for poly-dispersed particles can be measured by using NPC and it is considered that PSD with molar concentration spectra can give detail information of abrasive grain in suspension for quality management of CMP slurry. • A novel particle sizing method using nanoparticle chip (NPC) was proposed for particle size distribution analysis. • NPC can maintain the dispersed condition of poly-dispersed particles in suspension. • Molar concentration spectra are suggested to apply in quality of management of nanoparticles. • Molar concentration spectra can show the mean diameter, the variance of the diameters, and molar concentration. [ABSTRACT FROM AUTHOR]

Demand for applications of nanoparticles in electric architecture has been increasing. Nanoparticles provide new opportunities for improving circuit response. We discuss a novel method for evaluating nanoparticle sizes based on fluorescence anisotropy analysis. Particle size evaluation is possible through measurements of the rotational diffusion coefficient, which is sensitive to particle size. We develop a system for measuring rotational diffusion coefficients by using a fluorescent probe to label a particle. We report fundamental experiments that verify the feasibility of the proposed method. The rotational diffusion coefficients of gold nanoparticles with diameters ranging 6–20 nm were measured using the proposed method. The measured rotational diffusion coefficients decrease with increasing particle size. This finding indicates that nanoparticles smaller than 15 nm can be measured with fine resolution. [ABSTRACT FROM AUTHOR]

Positioning technology is one of the most important technologies for developing microsystems. In particular, displacement sensors are necessary for positioning devices with nanoscale accuracy. In this study, we propose a new displacement sensor that uses an interference scale as a linear scale and a laser-trapped microsphere as a sensing probe. This sensor has a wide measuring range, high resolution, and accessibility for narrow target areas. A glass microsphere was optically trapped by means of the laser trapping technique. Between the target surface and the probe, an interference scale was generated along the optical axis. The scale origin was fixed on the target surface. The distance between the probe and the target surface could be measured in terms of the shift in the interference scale. This study investigated the fundamental performance of the sensor. The resolution and accuracy of the sensor were 10 and ±50 nm, respectively; these values could be improved by using trapping lasers having shorter wavelengths. The measurable range was 250 μm. This sensor can provide useful displacement information from a target area having dimensions smaller than 15 μm. In addition, the displacement sensor can measure the distance even for surfaces inclined at angles less than 15°; thus, a flexible arrangement can be used to carry out measurements. In addition, the direction of displacement can be identified. [ABSTRACT FROM AUTHOR]

Abstract: Layer manufacturing is generally utilized for the development of micro electromechanical systems (MEMS) and micro total analysis systems (μTAS). However, the preparation of multiple masks and repetitive exposure procedure prevents the rapid fabrication of 3D microstructures. An active mask fabrication by using a liquid crystal display (LCD) as an electrically controllable photomask can simplify the layer manufacturing process. In addition, the gray-tone photolithography is available by using LCD lithography system, since the exposure distribution is easily controlled by an LCD. We have developed the LCD mask exposure system by using UV light source. Firstly, the patterning characteristics of the UV photoresist by exposing line and space patterns are evaluated, and then, a fundamental step shape is produced in order to verify the feasibility of gray-tone UV photolithography by using LCD. A shape with a different height can be fabricated without any repetitive exposure and development procedures. Finally, we confirmed the high patterning resolution such as 11μm using check patterns and fabricated 3D step shapes by using the LCD as a gray-scale photomask. [Copyright &y& Elsevier]

When a microsphere is trapped near a surface by single-beam gradient force trapping, the standing wave is generated between the microsphere and the surface, where abrupt motion along the optical axis (jumping) is observed corresponding to displacement of the surface. This jumping distance is on the order of a few hundred nanometers. In the vicinity of the surface, intensity of retro-reflected light is increased so that the averaged position of the jumping is shifted up on the order of several micrometers. Therefore wide-range and high-resolution position measurement technique is required. In this article, we proposed to apply a chromatic confocal sensor to measure the axial position of the microsphere in the standing wave. It was experimentally validated that the position of the microsphere could be measured with a resolution of 10 nm and a measuring range of 3 µm. [ABSTRACT FROM PUBLISHER]

Laser trapping is becoming an important technique for microsystem technologies. To apply it to industrial uses, it should be developed to function in air. However, there is not much research about laser trapping in air. One of the reasons is the difficulty of trapping micro-objects. Therefore, we have proposed a new technique to trap micro-objects in air. In particular, we focused our attention on the substrate where the micro-object is set. By applying a textured surface and employing tungsten carbide as the substrate material, the trapping probability was improved by a remarkable amount. Although a certain degree of improvement was attained, the trapping was still not perfect. To ascertain the forces working on the micro-object, an analytical calculation of the adhesion forces and an electromagnetic simulation of the optical forces were implemented. Based on these calculations, we discuss what the most important factor is for successful laser trapping in air. [ABSTRACT FROM AUTHOR]

Abstract: A novel contact probing method for microdevices with high aspect ratio or biological samples is proposed. In this technique, a dielectric microsphere is optically trapped by an optical fiber and used as a touch probe. In the simulations, the finite difference time domain (FDTD) method and Maxwell stress theory are applied to obtain a suitable shape for the tip of the optical fiber. The results show that it is possible to trap the microsphere by using a single optical fiber. In experiments, single fiber optical trapping is successfully demonstrated by considering the simulation results. In order to use the trapped microsphere in the touch probe, the intensity of the reentered beam that is reflected from the surface of the microsphere is monitored. When the probe is in contact with the surface of the object, the intensity of the beam changes and this change is used as the contact signal. Because the probe is trapped optically and the trapping force is very small, this system can be used in a low invasive method. [Copyright &y& Elsevier]

Abstract: Using complete sequences of cytochrome b (cyt b) and control region (CR; D-loop) genes of mitochondrial DNA, we investigated the phylogenetic relationships and phylogeography among populations of the salamander Hynobius tokyoensis in northern Japan. Inclusion of populations from Aichi, Chubu region within Hynobius nebulosus by previous results was confirmed because they formed a clade with H. nebulosus. Monophyly of H. tokyoensis was supported in all trees analyzed, and two clades consistently emerged: clade A from northeastern Kanto (Ibaraki) to southern Tohoku (Fukushima), and clade B from the remaining area south of northern Kanto (Tochigi). These two clades are estimated to have an old history of divergence during the late Pliocene, when the present-day Kanto Plain was under the sea. Within clade B, three haplotypes groups (I–III) are hypothesized to have diverged more recently, i.e., between the early and mid-Pleistocene, probably in relation to glacial events. The ancestral groups I and II were separated at the present-day western Kanto and Boso Peninsula areas, respectively, and subsequently, group II invaded northward to the present-day northern Kanto area and gave rise to group III. Populations of the Miura Peninsula are thought to have multiple origins, one directly from Boso and another from a more recent southward invasion from the northern Kanto area. Cytochrome b appears to have evolved more quickly than CR genes in H. tokyoensis, and thus will be more useful for phylogenetic analyses and formulating conservation measures. [Copyright &y& Elsevier]

Colloidal ceria is expected to be a candidate of alternative slurry for glass substrate CMP because the slurry particles are small and have a regular shape comparing to conventional calcined ceria particles. Thanks to the characteristics, the colloidal ceria can generate a high quality surface in glass substrate CMP, but removal rate (RR) is smaller than that of calcined ceria. In order to improve the RR, KOH was added to the colloidal ceria. KOH additives make colloidal ceria particles aggregate and improve RR close to that of calcined ceria. By evaluating the extent of aggregation with and without ultrasonic dispersion, it was found there was a strong correlation with KOH concentration to aggregation strength and RR. To obtain further RR and to reduce the consumption of slurry, influence of polishing pressure and slurry concentration on polishing characteristics was investigated. As the polishing pressure increased, the RR improved, while slurry residue occurred partly on the edge of the substrate surface. The slurry residue was restrained by decreasing slurry concentration. Furthermore, although scratches in the nanometer order increase slightly under high polishing pressure, they are smaller than those by calcined ceria slurry. By controlling the degree of aggregation of colloidal ceria, we have achieved both high RR and high quality surface. • Colloidal ceria slurry aggregates by adding KOH. • Aggregated colloidal ceria improves removal rate close to that of calcined ceria in CMP. • KOH concentration and aggregated strength of colloidal ceria have a strong correlation. • Even in aggregated state, colloidal ceria slurry maintains high surface quality. [ABSTRACT FROM AUTHOR]

Lead (Pb) poisoning is widespread among raptors and water birds. In Japan, fragments of Pb ammunition are still found in endangered eagles although more than 10 years have passed since legislation regarding use of Pb ammunition was introduced. This study was performed to investigate Pb exposure in raptors from various locations in Japan. We measured hepatic and renal Pb concentrations and hepatic Pb isotope ratios of Steller's sea eagles ( Haliaeetus pelagicus ), white-tailed sea eagles ( Haliaeetus albicilla ), golden eagles ( Aquila chrysaetos ), and 13 other species (total 177 individuals) that were found dead, as well as blood samples from three eagles found in a weakened state during 1993–2015 from Hokkaido (northern part), Honshu (the main island), and Shikoku (a southern island) of Japan. In the present study in Hokkaido, one quarter of the sea eagles showed a high Pb concentration, suggesting exposure to abnormally high Pb levels and Pb poisoning. Pb isotope ratios indicated that endangered Steller's sea eagle and white-tailed sea eagle were poisoned by Pb ammunition that was used illegally in Hokkaido. In other areas of Japan, both surveillance and regulations were less extensive than in Hokkaido, but Pb poisoning in raptors was also noted. Therefore, Pb poisoning is still a serious problem in raptors in various areas of Japan due to accidental ingestion of materials containing Pb, especially Pb ammunition. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the phylogenetic relationships and estimated the historical demography of the Japanese fire-bellied newt, Cynops pyrrhogaster, from Japanese mainlands using 1407-bp sequences of the mitochondrial DNA (NADH6, tRNAglu, cyt b) and 1208-bp sequences of nuclear DNA (Rag-1) genes. Phylogenetic trees based on mitochondrial DNA revealed four major haplotype clades (NORTHERN, CENTRAL, WESTERN, and SOUTHERN clades) within this species. Degree of genetic differentiation among major haplotype clades was very large for intraspecific variation, suggesting this species to be composed of four species lineages that replace each other geographically. Nuclear genetic variation presented no obvious patterns of geographic structure except for the distinctness of populations diagnosed by NORTHERN clade of mitochondrial haplotypes, suggesting results of incomplete lineage sorting. Current distribution and estimated divergence times for the genus Cynops suggest that the common ancestor of two Japanese species (C. pyrrhogaster and C. ensicauda from the Ryukyu Islands) had diverged at the edge of the continent corresponding to the present East China Sea and Central Ryukyus. Subsequent range expansion to Japanese mainland seems to have occurred in the middle Miocene. Population-genetic analyses indicated that all species lineages, except for the SOUTHERN one, experienced geographic population reductions and expansions associated with glacial and postglacial climatic oscillations. [Copyright &y& Elsevier]

Abstract: In the present study, concentrations of 13 elements (Li, Cr, Mn, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Hg) were measured in the tissues of the livers, the kidneys, pectoral muscles, lungs and brains of 13 avian species collected from the Kanto area of Japan. The difference in hepatic heavy metal levels of the grey herons from the two sites was compared. Metal levels in the sediment of the Tama River estuary, situated in the Haneda area, were also measured. These results revealed that heavy metal pollution is present in an aquatic area of Haneda. The accumulation patterns of Cu and Zn in the livers of grey herons appeared to be separated into two groups. Additionally, the present study includes the properties of other metal accumulations and their relationships in avian species. [Copyright &y& Elsevier]