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Through-silicon-via (TSV) interposers using silicon and copper represent a critical element in microelectronic packaging, as they bridge between fine-pitch inputs/outputs at the integrated circuit ...

Preserving the quality of carbon nanotubes (CNTs) is essential to fully utilize the characteristics in dispersions and other forms. To fabricate CNT dispersions retaining the quality, we propose to...

Suspended thin film carbon nanotubes with suitable mechanical strength are in high demand for applications such as sensors, particle filters, or thermoacoustic speakers. However, researchers working on the production and development of applications for thin films have found difficulty in evaluating their mechanical strength. This research shows the nano-indentation behavior of thin (

In this work, we demonstrate controlled introduction of O-functional groups on commercial carbon nanotube fibers (CNTFs) with different nanotube morphologies obtained by dry- and wet-spinning by treatment with gaseous ozone (O3(g)). Our test samples were (1) wet-spun fibers of smalldiameter (1–2 nm) singlewall (SW)-CNTs and (2) dry-spun fibers containing large-diameter (20 nm) multiwall (MW)-CNTs. Our results indicate that SW-CNTFs undergo oxygenation to a higher extent than MW-CNTFs due to the higher reactivity of SW-CNTs with a larger curvature strain. Oxygenation resulting from O3 exposure was evidenced as increase in surface O atomic% (at% by X-ray photoelectron spectroscopy, XPS) and as reductions in G/D (by Raman spectroscopy) as well as electrical conductivities due to changes in nanotube graphitic structure. By XPS, we identified the emergence of various types of O-functionalities on the fiber surfaces. After long duration O3 exposure (>300 s for SW-CNTFs and >600 s for MW-CNTFs), both sp2 C═O (carbonyl) and sp3 C–O moieties (ether/hydroxy) were observed on fiber surfaces. Whereas, only sp3 C–O (ether/hydroxy) components were observed after shorter exposure times. O3 treatment led to only changes in surface chemistry, while the fiber morphology, microstructure and dimensions remained unaltered. We believe the surface chemistry controllability demonstrated here on commercial fibers spun by different methods containing nanotubes of different structures is of significance in aiding the practical application development of CNTFs.

Carbon nanotubes (CNTs) have garnered tremendous attention as building blocks for self-supporting membranes owing to remarkable developments in the manufacturing technology of high-quality CNT films. CNT films are expected to be applied in a wide range of applications, such as ultrafiltration membranes and as switching or sensing elements in microelectromechanical systems. However, the main challenge has been in fabricating CNT films by versatile and scalable processes suitable for industrial production while retaining lab-scale high performance. In this work, we succeed in fabricating macroscale (10 cm2) free-standing CNT films with thicknesses as low as 200 nm showing tensile strengths of ∼166 MPa by simple, versatile, and scalable blade-coating of CNT suspensions. Our study demonstrates that it is possible to control CNT film bundle size distribution and pore structure by controlling the CNT dispersibility and entanglement in the suspensions. We find that controlling bundle size distribution, pore structure uniformity, and packing can lead to five-fold, four-fold, and three-fold higher tensile strengths, fracture strain, and Young’s modulus, respectively, compared to films with poorer uniformity and packing.

We propose vacuum annealing to purify carbon nanotube wires (CNTWs) manufactured from surfactant dispersions by removing residual carbonaceous impurities (surfactant and solvent) included during wire-spinning. We analysed the CNTW purity post-annealing vs. treatment temperature and time by scanning electron microscopy, Raman spectroscopy, and thermogravimetry. Our results suggest that maximal purification is achieved after annealing at 800 °C (for ≥3 h) or at 1000 °C (for ≥1 h). The optimally purified wires show higher CNT content and G/D (∼93 wt% and >30, respectively) than the untreated wires (∼71 wt% and 25, respectively).

We report the importance of carbon nanotube (CNT) wire Cu electrodeposition parameters to fabricate structurally uniform CNT-Cu wire composites as potential lightweight Cu wire substitutes. We find promoting Cu deposition within CNT wires (CNTWs) and controlling surface deposition as key to obtaining composite wires containing a continuous Cu matrix and nanotubes distributed homogeneously (defined as structurally uniform CNT-Cu wires). We applied an optimized 2-step Cu electrodeposition to obtain the structurally uniform CNT-Cu wires. The 2-step electrodeposition included (i) initial Cu-seeding within hydrophobic CNTWs from an organic electrolyte (Cu(CH 3 COO) 2 in CH 3 CN), followed by (ii) seed growth by routinely used aqueous acidified CuSO 4 deposition. We find both steps crucial to realize internal Cu deposition and composite wires with even CNT/Cu mixing. We tested the effect of various electrodeposition parameters at both stages, such as current density, electrolyte concentration, and time on CNT-Cu wire surface and bulk Cu distribution. Our results show that only parameters allowing for slow (∼ 4 μg/h per cm of wire) and moderate (∼ 145 μg/h per cm of wire) Cu deposition rates during the seeding and seed growth stages, respectively lead to high internal Cu filling and controlled surface deposition and hence, structurally uniform CNT-Cu wires. These structurally uniform CNT-Cu wires obtained under optimal conditions are 2/3rd as light as Cu (density: ∼5.2 g/cm 3 ) with 40–45 vol% CNTs and 98 wt% Cu.

We report ultralong conducting lightweight multiwall carbon nanotube (MWCNT)-Cu composite wires with MWCNTs uniformly distributed in a continuous Cu matrix throughout. With a high MWCNT vol% (40–45%), the MWCNT-Cu wire density was 2/3rd that of Cu. Our composite wires show manufacturing potential because we used industrially compatible Cu electrodeposition protocols on commercial CNT wires. Further, we systematically varied Cu spatial distribution on the composite wire surface and bulk and measured the associated electrical performance, including resistivity (ρ), temperature dependence of resistance, and stability to current (measured as current carrying capacity, CCC in vacuum). We find that a continuous Cu matrix with homogeneous MWCNT distribution, i.e., maximum internal Cu filling within MWCNT wires, is critical to high overall electrical performances. Wires with maximum internal Cu filling exhibit (i) low room temperature ρ, 1/100th of the starting MWCNT wires, (ii) suppressed resistance-rise with temperature-increase and temperature coefficient of resistance (TCR) ½ that of Cu, and (iii) vacuum-CCC 28% higher than Cu. Further, the wires showed real-world applicability and were easily soldered into practical circuits. Hence, our MWCNT-Cu wires are promising lightweight alternatives to Cu wiring for weight-reducing applications. The low TCR is specifically advantageous for stable high-temperature operation, e.g., in motor windings.

In order to establish design rules for micro-supercapacitors (micro-SCs), the influence of electrode shape, specifically aspect ratio, was investigated on the operational speed of micro-SCs. The operational speed, as characterized by the relaxation time constant, was found to nonlinearly decrease (85 to ∼0.5 ms) as the electrode aspect ratio increased (0.2 to 7). This was achieved by simplifying the electrode design to a basic parallel electrode geometry. In so doing, all factors, such as electrode height, volume, electrolyte volume, inter-electrode separation, etc. could be maintained while adjusting the electrode aspect ratio (AR). In addition, the results showed that the relaxation time constant showed only moderate improvement for aspect ratios above 1, illustrating the limitation on this single shape parameter. Investigation into the underlying reasons for this behavior showed that the observed dependence of the relaxation time constant with the electrode AR originated from differences in the electrolyte resistance within the electrode for each electrode shape as determined by electrochemical impedance spectroscopy. Although these results demonstrate that the operational speed of a micro-SC can be improved by increasing the electrode AR, our results also show that this factor alone is insufficient to improve the speed into the microsecond regime within our experimental scope.

We demonstrate anisotropic, vertical deep etching of graphite and densely packed carbon nanotube (CNT) thick layer beyond the micrometer scale, which representing the first step toward nanocarbon bulk micromachining. This micromachining process is compatible with standard lithography and therefore allows the fabrication of graphite and CNT architectures with 1 μm lateral resolution and up to 10 μm scale depth.

New lithographically processable materials with high ampacity are in demand to meet the increasing requirement for high operational current density at high temperatures existing in current pathways within electronic devices. To meet this demand, we report an approach to fabricate a high ampacity (similar to 100 times higher than Cu) carbon nanotube-copper (CNT-Cu) composite into a variety of complex nano-scale, planar and multi-tiered current pathways. The approach involved the use of a two-stage electrodeposition of copper into a pre-patterned template of porous, thin CNT sheets acting as the electrode. The versatility of this approach enabled the realization of completely suspended multi-tier, dielectric-less 'air-gap' CNT-Cu circuits that could be electrically isolated from each other and are challenging to fabricate with pure Cu or any metal. Importantly, all such complex structures, ranging from 500 nm to 20 mu m in width, exhibited similar to 100-times higher ampacity than any known metal, with comparable electrical conductivity as Cu. In addition, CNT-Cu structures also exhibited a superior temperature stability compared to the similar to 10-times wider Cu counterparts. We believe that the combination of our approach and the properties demonstrated here are vital achievements for the future development of efficient and powerful electrical devices.

A method for the selective semiconducting single-walled carbon nanotube (SWCNT) growth over a continuous range from 67% to 98%, within the diameter range of 0.8-1.2 nm, by the use of a "catalyst conditioning process" prior to growth is reported. Continuous control revealed an inverse relationship between the selectivity and the yield as evidenced by a 1000-times difference in yield between the highest selectivity and non-selectivity. Further, these results show that the selectivity is highly sensitive to the presence of a precise concentration of oxidative and reductive gases (i.e. water and hydrogen), and the highest selectivity occurred along the border between the conditions suitable for high yield and no-growth. Through these results, a phenomenological model has been constructed to explain the inverse relationship between yield and selectivity based on catalyst deactivation. We believe our model to be general, as the fundamental mechanisms limiting selective semiconducting SWCNT growth are common to the previous reports of limited yield.

Background Polycystic ovary syndrome (PCOS) is a common ovulatory disorder that can be induced by sodium valproate (VPA). Patient We report a case of PCOS that developed in a 15-year-old girl with idiopathic epilepsy after she took VPA. VPA administration stopped her seizures, but it also led to weight gain and amenorrhea, and the patient was diagnosed with PCOS on the basis of diagnostic imaging and serological examination results. Cessation of VPA administration led to reduced weight gain and restored menstruation. Conclusions The risk of PCOS developing in patients with epilepsy is known to be high, and the association of VPA with PCOS is well established, so if physicians feel this is the best drug to prescribe for female patients with epilepsy, they should carefully monitor the patients' weight and menstruation, and immediately perform ovarian imaging and hormonal examinations if any abnormalities are observed.

Clothes represent a unique textile, as they simultaneously provide robustness against our daily activities and comfort (i.e., softness). For electronic devices to be fully integrated into clothes, the devices themselves must be as robust and soft as the clothes themselves. However, to date, no electronic device has ever possessed these properties, because all contain components fabricated from brittle materials, such as metals. Here, we demonstrate robust and soft elastomeric devices where every component possesses elastomeric characteristics with two types of single-walled carbon nanotubes added to provide the necessary electronic properties. Our elastomeric field effect transistors could tolerate every punishment our clothes experience, such as being stretched (elasticity: ∼ 110%), bent, compressed (4.0 MPa, by a car and heels), impacted (6.26 kg m/s, by a hammer), and laundered. Our electronic device provides a novel design principle for electronics and wide range applications even in research fields where devices cannot be used.

Background: Although cervical dilatation curves are crucial for appropriate management of labor progression, abnormal labor progression and obstetric interventions were included in previous and widely-used cervical dilatation curves. We aimed to describe the cervical dilatation curves of normal labor progression in pregnant Japanese females without abnormal labor progression and obstetric interventions. Methods: We completed retrospective obstetric record reviews on 3172 pregnant Japanese females (parity = 0, n = 1047; parity = 1, n = 1083; parity ≥ 2, n = 1042), aged 20 to 39 years old at delivery, with pregravid body mass indices of less than 30. All patients underwent spontaneous deliveries with term, singleton, cephalic and live newborns of appropriate-for-gestational age birthweight, without adverse neonatal outcomes. We characterized labor progression patterns by examining the relationship between elapsed times from the full dilatation and cervical dilatation stages, and labor durations by examining the distribution of time intervals from one cervical dilatation stage, to the next, and ultimately to the full dilatation. Results: Fastest cervical changes occurred at 6 cm (primiparas) and 5 cm (multiparas) of dilatation. The 95%tile of labor progression took over 3 hours to progress from 6 cm to 7 cm (primiparas), and over 2 hours to progress from 5 cm to 6 cm (multiparas). The 5%tile of traverse time to the full dilatation, during the active phase, was less than 1 hour (primiparas) and 0.5 hours (multiparas). At the end of the active phase, no deceleration phase was observed. Conclusions: Active labor may not start until 5 cm of dilatation. At the beginning of the active phase, cervical dilatation was slower than previously described. These results may reduce opportunities for obstetric interventions during labor progression.

We have developed the coating and microfabrication technique of the single walled carbon nanotubes and its composite with rubbers in the way compatible to the conventional device technology in order to incorporate the unique properties of SWCNTs, such as diversity of electrical properties depending on the charity, mechanical flexibility and stretchability arising from the formation of network structure, with device applications. Utilizing the process technologies, we have recently succeeded in assembling the field effect transistor of all rubbery materials on the rubber substrate, demonstrating that it exhibits the transistor performance comparable to the conventional CNT-transistors and significant tolerance to the mechanical loadings. The stretchability and robustness of our FET is promising for the wearable electronics, especially which is used for human body.

Aim The aim of this study was to elucidate the clinical characteristics and risk factors for amniotic fluid embolism (AFE). Methods We performed a retrospective case study analysis of patients using medical records and autopsy records. The diagnosis of AFE was based on the presence of clinical symptoms using Clark's criteria and autopsy results. We analyzed patient records from a 29-year period in three hospitals affiliated with the Nippon Medical School in Japan. Results Ten diagnoses of AFE were found in the records. First, we classified AFE patients into two types based on the initial presenting symptoms: post-partum hemorrhage and cardiopulmonary collapse. Fifty percent of the patients initially presented with post-partum hemorrhage and disseminated intravascular coagulation. Most were diagnosed with post-partum hemorrhage or uterine atony at AFE onset. Similarly, 50% presented with cardiopulmonary arrest or pulmonary arrest as initial symptoms, and most were diagnosed with eclampsia. Second, risk factors for AFE included advanced maternal age, multiparity, increased intrauterine pressure and disruptions of the uterine vasculature. Third, the case fatality rate was 70%. Fourth, squamous cells were observed in maternal central venous blood of five patients. Conclusion AFE patients were classified into two types based on presenting signs and symptoms. Knowledge of the various initial symptoms of AFE enables a correct diagnosis.

Ambiguous genitalia (AG) is a morphological diagnosis defined as genitalia not typical of a male or female. Findings mimicking AG, such as penoscrotal anomalies, anorectal malformations, and perineal lipomatous tumors, may prevent accurate identification of the fetal sex. We report a case of bifid scrotum and anocutaneous fistula associated with a perineal lipomatous tumor complicated by temporary bilateral cryptorchidism in utero, which were findings mimicking AG. Several perineal anomalies are associated developmental occurrences. In the present case, the combination of bifid scrotum and temporary bilateral cryptorchidism in the male fetus mimicked the combination of clitoromegaly and prominent labia, which are commonly observed in female fetuses. However, serial systemic assessments using prenatal 2-D/3-D ultrasonography and magnetic resonance imaging were unable to detect the anocutaneous fistula and differentiate the perineal lipomatous tumor. This case report suggests that the prenatal detection of perineal abnormalities may warn obstetricians of potentially undetected congenital perineal anomalies.

A rational torsion sensing material was fabricated by wrapping aligned single-walled carbon nanotube (SWCNT) thin films onto the surface of a rod with a predetermined and fixed wrapping angle without destroying the internal network of the SWCNTs within the film. When applied as a torsion sensor, torsion could be measured up to 400 rad/meter, that is, more than 4 times higher than conventional optical fiber torsion sensors, by monitoring increases in resistance due to fracturing of the aligned SWCNT thin films.

Aim: The aim of the present study was to elucidate the clinical characteristics of pregnancy-associated maternal deaths. Methods: We performed a retrospective analysis with medical records and autopsy reports of cases of pregnancy-associated deaths. We collected information on all maternal deaths related to pregnancy that occurred in 3 hospitals affiliated with Nippon Medical School in Japan from January 1, 1984, to Decem- ber 31, 2014. Data analyzed were maternal age, past medical history, parity, gestational age, clinical signs and symptoms, cause of death, and maternal autopsy findings. Results: A total of 26 maternal deaths occurred during the 31-year study period. Autopsies were per- formed for 16 patients (61.5%). The 26 deaths included 19 (73.1%) classified as direct maternal deaths and 7 (26.9%) classified as indirect maternal deaths. The mean maternal age at death was 33.1±4.3 years (range, 26―41 years). The highest percentage of women was aged 35 to 39 years (38.5%). Of the 26 maternal deaths, 69% occurred at 32 to 41 weeks of gestation. In cases of direct maternal death, the leading causes were amniotic fluid embolism (7 cases, 27.0% of all deaths) and hemorrhage (6 cases, 23.1% of all deaths). In cases of indirect obstetric deaths, the causes included cardiovascular disorders, cerebrovascular disorders, sepsis due to group A streptococcal infection, and hepatic failure of unknown etiology. Conclusions: Amniotic fluid embolism was the leading cause of maternal deaths and was followed by obstetric hemorrhage. To prevent and reduce the number of maternal deaths in Japan, further basic and clinical research on amniotic fluid embolism is required. (J Nippon Med Sch 2016; 83: 6―14)

The aim of our study was to use brachial-ankle pulse wave velocity (baPWV) measurements to noninvasively assess the effect of exercise training on arterial stiffness in normal pregnant women. Arterial stiffness was assessed at the beginning of the early second trimester of pregnancy and 1 month after delivery in 17 women with normal singleton pregnancies who exercised regularly throughout pregnancy: 81 matched controls were used for comparison. No significant differences were observed in baPWV between the exercise and control groups at the beginning of the second trimester. BaPWV 1 month after delivery (1160.2 ± 109.1 cm·second(-1)) was signifi-cantly higher than that in the early second trimester (1116.7 ± 87.9 cm·second(-1)) in the control group (indicating increased arterial stiffness), but not in the exercise group (1145.9 ± 88.1 cm/second vs 1122.7 ± 100.2 cm·second(-1), respectively: not significant). The results indicated that regular maternal exercise training decreased arterial stiffness in normal pregnant women, which suggests that regular exercise may help prevent hypertensive disorders during pregnancy. Key pointsRegular maternal exercise training decreased arterial stiffness in normal pregnant women, which suggests that regular exercise may help prevent hypertensive disorders during pregnancy.Maternal exercise suggests that disturbances in arterial function during pregnancy may be prevented by regular exercise.

Aim: Intrapartum management guidelines based on fetal heart rate classification comprising a 5-tier system (Levels 1-5) was proposed by the Perinatology Committee of the Japan Society of Obstetrics and Gynecology (JSOG). This study aimed to assess the reproducibility and clinical usefulness of this classification. Methods: For assessing intraobserver and interobserver reproducibility in the interpretation of fetal heart rate tracing, 2 obstetricians reviewed 247 fetal heart rate tracings using the JSOG classification (Level 1, normal; Level 2, benign variant; Level 3, mild variant; Level 4, moderate variant; and Level 5, severe variant) and a subjective 3-tier classification (normal, equivocal, and ominous). In a separate series, we investigated whether the JSOG classification is related to early neonatal outcome and the delivery mode in 96 deliveries. Results: Weighted kappa coefficients of intraobserver and interobserver reproducibility in the interpretation of fetal heart rate tracings based on the JSOG classification were 0.73 to 0.77 and 0.70, respectively. In the subjective classification, these values were 0.69 to 0.72 and 0.59. There was a progressive increase in the rate of instrumental or cesarean deliveries across the 5 levels of the JSOG classification (P

We report a general approach to overcome the enormous obstacle of the integration of CNTs into devices by bonding single-walled carbon nanotubes (SWNTs) films to arbitrary substrates and transferring them into densified and lithographically processable "CNT wafers". Our approach allows hierarchical layer-by-layer assembly of SWNTs into organized three-dimensional structures, for example, bidirectional islands, crossbar arrays with and without contacts on Si, and flexible substrates. These organized SWNT structures can be integrated with low-power resistive random-access memory.

We present research progress made in developing copper/carbon nanotube composites (Cu/CNT) to fulfil a growing demand for lighter copper substitutes with superior electrical, thermal and mechanical performances. Lighter alternatives to heavy copper electrical and data wiring are needed in automobiles and aircrafts to enhance fuel efficiencies. In electronics, better interconnects and thermal management components than copper with higher current- and heat-stabilities are required to enable device miniaturization with increased functionality. Our literature survey encouragingly indicates that Cu/CNT performances (electrical, thermal and mechanical) reported so far rival that of Cu, proving the material's viability as a Cu alternative. We identify two grand challenges to be solved for Cu/CNT to replace copper in real-life applications. The first grand challenge is to fabricate Cu/CNT with overall performances exceeding that of copper. To address this challenge, we propose research directions to fabricate Cu/CNT closer to ideal composites theoretically predicted to surpass Cu performances (i.e. those containing uniformly distributed Cu and individually aligned CNTs with beneficial CNT–Cu interactions ). The second grand challenge is to industrialize and transfer Cu/CNT from lab bench to real-life use. Toward this, we identify and propose strategies to address market-dependent issues for niche/mainstream applications. The current best Cu/CNT performances already qualify for application in niche electronic device markets as high-end interconnects. However, mainstream Cu/CNT application as copper replacements in conventional electronics and in electrical/data wires are long-term goals, needing inexpensive mass-production by methods aligned with existing industrial practices. Mainstream electronics require cheap CNT template-making and electrodeposition procedures, while data/electrical cables require manufacture protocols based on co-electrodeposition or melt-processing. We note (with examples) that initiatives devoted to Cu/CNT manufacturing for both types of mainstream applications are underway. With sustained research on Cu/CNT and accelerating its real-life application, we expect the successful evolution of highly functional, efficient, and sustainable next-generation electrical and electronics systems.

We present the influence of density, structural regularity, and purity of carbon nanotube wires (CNTWs) used as Cu electrodeposition templates on fabricating homogeneous high-electrical performance CNT–Cu wires lighter than Cu. We show that low-density CNTWs ( 90 wt %) are essential for making homogeneous CNT–Cu wires. These homogeneous CNT–Cu wires show a continuous Cu matrix with evenly mixed nanotubes of high volume fractions (~45 vol %) throughout the wire-length. Consequently, the composite wires show densities ~5.1 g/cm3 (33% lower than Cu) and electrical conductivities ~6.1 × 104 S/cm (>100 × CNTW conductivity). However, composite wires from templates with higher densities or structural inconsistencies are non-uniform with discontinuous Cu matrices and poor CNT/Cu mixing. These non-uniform CNT–Cu wires show conductivities 2–6 times lower than the homogeneous composite wires.

The reaction behavior and growth kinetic of reaction layer were investigated in the Ni contact to n-type 6H-SiC. Annealing was performed at temperature in the range between 800 and 1000 °C for 1 to 240 minutes in Ar atmosphere. The interface reaction of Ni/SiC starts with Ni diffusion into SiC. Ni3Si is initially precipitated and subsequently forms the continuous layer of d-Ni2Si. Kirkendall voids are formed at the reaction front. Carbon is segregated in the interface layer of nickel silicide. The growth rate of the interface layer follows a parabolic law, meaning that the growth rate is controlled by diffusion. The growth occurs in two steps at all examined temperatures: a fast growth is followed by a slow growth. In addition, in the late stage, the growth rate changes dramatically below and above 850°C. The observed growth kinetic can be explained by the difference of Ni diffusivity and the required concentration change for phase transition depending on the phase composition and structure. The d-Ni2Si is formed in the early stage, while the e-Ni3Si2 and q-Ni2Si are formed in the late stage below and above 850°C, respectively.

The adhesion strength of Cu/(Ta–x% N, Ta/TaN)/SiO2/Si was investigated and the feasibility of the nanoscratch technique was evaluated. Because of the grain orientation dependence of critical load owing to elastic/plastic anisotropy, the interface adhesion measured in the mix-textured films of and showed a wide-range data spread to higher adhesion strength compared with the highly textured films. The adhesive energy derived from the measured critical load by considering the residual stress and the effect of grain orientation by the aid of finite element method calculation showed a reasonable agreement with theoretical work of adhesion. It was revealed that the adhesion strength of Cu/Ta–x% N decreases with increasing nitrogen concentration. This tendency can be associated with increasing number of weak Cu–N bonding along the Cu/barrier interface.

Mechanical processes of the nanoscratch test are investigated using a finite element analysis of Cu/Ta/SiO2/Si multilayer films. The calculated stress distribution at the moment of delamination suggests that delamination occurs in a small region of approximately 100 nm. The driving force for delamination is the stress concentration due to strain-incompatibility at the Cu/Ta interface resulting from the large plastic deformation in Cu. The degree of stress concentration is found to depend on internal variables, such as plastic deformation, residual stress, and the elastic modulus, and on the magnitude of lateral force.

In an interconnect structure of advanced large scale integrated (LSI) circuits, Cu diffusion leads to migration failure, known as stress migration and electro migration. In order to prevent these failures and to improve interconnect reliability, interface properties should be improved between Cu and a barrier layer. Among various interface properties, adhesion strength can be measured easily and be used as a representative interface property related to reliability. This paper show the relationship of interface adhesion strength with wettability, energy, and diffusivity. Then the effects of the adhesion strength on SM and EM reliability are discussed. Finally, key factors to improve the adhesion strength are proposed, together with our recent experimental evidences.

The surface acoustic wave technique is a non-contact, non-destructive opto-acoustic technique used to measure film thickness and material properties, such as elastic properties and density. Simulation of acoustic wave velocity dispersion revealed that the contribution density makes is larger in the first mode, whereas the modulus makes a larger contribution in the second mode. The effect of thickness does not depend on the wavelengths and oscillation modes as the density and modulus. In fact, the dispersion curves measured experimentally in the electro-deposited Cu films show more variation in second mode during self-anneal, while the difference between two samples, which contain different impurity level, is more significant in first mode. The velocity change during self-anneal is mainly due to the modulus change, which result from the texture change accompanied with grain growth. In contrast, a different impurity concentration causes density variation, which is considered to be related to the change of formation energy of voids or vacancy-type defect. These results coincide with the simulation. The understanding obtained in the present investigation suggests the possibility to improve the precision of thickness or material properties determination and the possibility to determine density and modulus simultaneously by analyzing the acoustic wave velocity dispersion.

Stress voiding was investigated in damascene Cu lines embedded in Ta/TaN/SiO2/Si. Microstructure was observed before and after heat treatment at 723 K using a focused ion beam (FIB) technique. The distribution of thermal stress was calculated using a three-dimensional finite element method (FEM). FIB observation revealed that slit-like voids were formed at trench shoulders both before and after heat treatment. FEM calculation indicated that a large shear stress concentration occurred at the voided sites. The coincidence between the FIB observation and the FEM calculation suggests that the slit-like voids were formed by shear-mode delamination of Cu from the Ta/TaN barrier layer.

Background To evaluate whether consecutive cervical length measurements can predict preterm cesarean section in women with complete placenta previa. Methods Seventy-one women with complete placenta previa were retrospectively categorized into women who delivered preterm due to massive hemorrhage (the preterm cesarean section group, n = 28) and those delivered at term (the control group, n = 43). Maternal characteristics, delivery outcomes, and cervical lengths serially measured at least every 2 weeks from 24 weeks' gestation until delivery were compared. The relationship between cervical length and preterm cesarean section was analyzed. Results Cervical length gradually decreased with advancing gestational age. After 26 weeks' gestation, this decrease was significantly more rapid in the preterm cesarean section group. Cervical length before cesarean section in the preterm cesarean section group was significantly shorter than that in the control group. Just before cesarean section, 71.4% of the preterm cesarean section group presented with cervical lengths of ≤35 mm, whereas only 34.9% of the control group had cervical lengths of ≤35 mm (odds ratio 4.67, 95% confidence interval 1.66–13.10, p = 0.006). Conclusions In women with complete placenta previa, decrease in cervical length to ≤35 mm was associated with increased risk of preterm cesarean section due to massive hemorrhage. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 43:17–22, 2015

To assess the safety of various methods of induced abortion when used before 12 weeks of pregnancy in Japan.A retrospective study was undertaken of induced abortions conducted between January 1 and December 31, 2012. Questionnaires were sent to 4154 institutions that employed doctors who were licensed to conduct induced abortions. Information was obtained about the numbers of induced abortions performed before 12 weeks, methods, complications, and routine management.Completed questionnaires from 2434 institutions showed that 100 851 induced abortions had been performed. Vacuum aspiration (VA) was used in 20 458 (20.3%) abortions, VA with sharp curettage in 47 148 (46.8%), dilatation and curettage (DC) in 32 958 (32.7%), and medical abortion in 287 (0.3%). Overall, 358 complications were reported (355.0 per 100000 procedures). The rate of complications was significantly higher after DC than after VA and after VA with sharp curettage (P0.001 for both). However, incomplete abortion requiring repeat procedures was the only complication that was significantly associated with DC (P0.001).DC can be safely used for induced abortion before 12 weeks of pregnancy, but changing from DC to VA could reduce incomplete abortions and improve the safety of induced abortions before 12 weeks of pregnancy in Japan.

Ambiguous genitalia (AG) is a morphological diagnosis defined as genitalia not typical of a male or female. Findings mimicking AG, such as penoscrotal anomalies, anorectal malformations, and perineal lipomatous tumors, may prevent accurate identification of the fetal sex. We report a case of bifid scrotum and anocutaneous fistula associated with a perineal lipomatous tumor complicated by temporary bilateral cryptorchidism in utero, which were findings mimicking AG. Several perineal anomalies are associated developmental occurrences. In the present case, the combination of bifid scrotum and temporary bilateral cryptorchidism in the male fetus mimicked the combination of clitoromegaly and prominent labia, which are commonly observed in female fetuses. However, serial systemic assessments using prenatal 2-D/3-D ultrasonography and magnetic resonance imaging were unable to detect the anocutaneous fistula and differentiate the perineal lipomatous tumor. This case report suggests that the prenatal detection of perineal abnormalities may warn obstetricians of potentially undetected congenital perineal anomalies.

The origin of stress voiding in heat-treated Cu thin films was investigated in relation to microstructure. Voids were observed at the intersections of twins with grain boundaries or with other twins. Twin interfaces were accompanied by stress concentration due to the elastic anisotropy. Stress concentration was found to act as a driving force for stress voiding. Twin formation and associated void formation could be avoided by controlling the film texture. Texture transition from (111) to (100) was observed in heat-treated films with increasing the film thickness from 200 nm to 300 nm. The (100) oriented films did not show any voids or hillocks. The excellent stress-migration resistance in the (100) oriented films could be attributed to the absence of twins and by small thermal stresses.

To investigate the possible physiological relevance of extra-thyroidal production of reverse T3 (rT3) in hyperemesis gravidarum, measurements of serum rT3, free T3 (FT3), free T4, (FT4), and nonesterified fatty acids (NEFA) were correlated with weight loss of hyperemetic women. All the thyroid hormones, NEFAs and weight loss were significantly higher in hyperemesis gravidarum than in control subjects, and also higher than in those with milder symptoms of morning sickness (p < 0.05). Elevations of FT3, FT4 and NEFAs correlated with the extent of weight loss, the latter taken as the index of the severity of hyperemesis gravidarum (p < 0.05). Only rT3 correlated with both weight loss and the rate of lipolysis, as reflected by elevations of NEFAs (p < 0.05). The data are consistent with a shift from T3 to rT3 as products of 5′-monodeiodination of thyroxine in hyperemesis gravidarum. Because reverse T3 is physiologically inactive a control mechanism may be postulated wherein T3 production is minimized, thereby reducing weight loss and lipolysis in patients with hyperemesis gravidarum.