A Study of Difference in Reflow Characteristics Between Electroplated and Sputtered Cu in a Dual-Damascene Fabrication Process for Silicon Semiconductor Devices

The difference in reflow characteristics between electroplated and sputtered Cu films during high-temperature high-pressure treatment was confirmed, and the basis for this difference was analyzed. Using test element groups containing a number of via holes, it was found that electroplated Cu films had much superior embedding characteristics compared with sputtered Cu films. This was confirmed by measurements of the stress–strain curves of these Cu films, which indicated that the strength at high temperature of the electroplated films was lower than that of sputtered films. Identification of lattice defects and analysis of the microstructure of these films were carried out by positron lifetime measurements and transmission electron microscopy, respectively. The results showed that a large quantity of vacancy clusters was present in the electroplated Cu films, and this increased to a maximum after isochronal annealing at 300°C. From the results, it was shown that Cu atoms in electroplated films with a large number of vacancy clusters diffuse rapidly at around 300°C, and this rapid diffusion contributes greatly to softening of the film and a promotion in reflow behavior. This study revealed that the reflow behavior of Cu films strongly depends on the presence of vacancy clusters within it.     

Long-term observation of glomerulonephritis induced by multiple injections with anti-Thy-1 antibody in rats

Multiple injections with a mouse monoclonal anti-rat Thy-1 antibody (five times, at weekly intervals) induced marked glomerular sclerotic lesions which are characterized by adhesion of glomerular capillaries to Bowman's capsule and persistent proteinuria in rats. Abnormal production of type I collagen and increased accumulation of type IV collagen and fibronectin were observed in these glomeruli. The glomerular expression of mRNA for these matrix components and transforming growth factor-beta1 (TGF-beta1) were markedly increased at 4 days after the last injections with anti-Thy-1 antibody, but decreased to below the levels of control rats at 5 weeks. This may be down-regulation of mRNA in mesangial cells. The glomerular sclerotic lesions were not progressive but the process of glomerular healing seemed to be retarded. The proteinuria and the glomerular adhesion were irreversible.     

Hue rotation (HR) and hue blending (HB): Real‐time image enhancement methods for digital component video signals to support red‐green color‐defective observers

The mutual understanding of color‐normal observers (CNOs) and color‐defective observers (CDOs) is now essential because personal color information display environments have been widely adopted. However, existing tools for CDOs offer only color discrimination; they fail to support color impression (ie, saturation and contrast). Therefore, we need a novel tool that offers help in distinguishing opponent colors, while preserving color saturation. We introduce two key techniques for realizing this difficult goal. The former is the repeated sequential display of the original and processed images to support the formation of unified correct percepts that provide discrimination of both red‐green and yellow‐blue opponent colors. One image, ie, original, exhibits correct yellow‐blue but distorted red‐green information for CDOs while the other, ie, processed, provides synthesized distinguishable red‐green but confusable yellow‐blue information for CDOs; here, hue rotation (HR) is useful for advanced users whereas hue blending (HB) is suitable for general. The latter is realized by the real‐time video processing available on smartphones; our algorithms support direct processing of the digital component video signal formats (eg, Y, C_R, and C_B). Subjective tests suggest that the two above‐mentioned algorithms will, along with embedding a lightweight real‐time dichromatic simulation facility for CNOs, greatly help the mutual understanding of CNOs and CDOs.     

Morphological changes of carbides during creep and their effects on the creep properties of inconel 617 at 1000 °C

Creep tests have been correlated with microstructural changes which occurred during creep of Inconel 617 at 1000 °C, 24.5 MPa. The following results were obtained: 1) Fine intragranular carbides which are precipitated during creep are effective in lowering the creep rate during the early stages of the creep regime (within 300 h). 2) Grain boundary carbides migrate from grain boundaries that are under compressive stress to grain boundaries that are under tensile stress. This is explained in terms of 1 the dissolution of relatively unstable carbides on the compressive boundaries, 2 the diffusion of the solute atoms to the tensile boundaries and 3 the reprecipitation of the carbides at the tensile boundaries. The rate of grain boundary carbide migration depends on grain size. 3) M₂₃C₆ type carbides, having high chromium content, and M₆C type carbides, having high molybdenum content, co-exist on the grain boundaries. M₂₃C₆ type carbides, however, are quantitatively predominant. Furthermore, M₆C occurs less frequently on the tensile boundaries than on the stress free grain boundaries. This is attributed to the difference of the diffusion coefficients of chromium and molybdenum. 4) The grain boundaries on which the carbides have dissolved start to migrate in the steady state creep region. The creep rate gradually increases with the occurrence of grain boundary migration. 5) The steady state creep rate depends not so much on the morphological changes of carbides as on the grain size of the matrix.     

Relationship of the structure of ureteral muscularis to in vitro spontaneous contractions

We investigated the anatomical structure of the smooth muscle layers of the mid portion of the canine ureter. In transverse sections the inner muscle bundles appear to be oriented longitudinally and the outer muscle bundles appear to be oriented in a circular configuration. In sections cut parallel with the longitudinal axis of the ureter, the inner and outer bundles appear to be oblique and are oriented in a mesh-line manner. In oblique sections, cut parallel with the helically oriented ureteral muscle, bundles appear to be oriented in a lengthwise configuration. These anatomical studies show that canine ureteral smooth muscle is composed of spiral fibers in a mesh structure and that helical muscle strips which include a significant percentage of continuous bundles have a greater capacity to generate spontaneous contractions in vitro than do transverse and longitudinal muscle strips.     

Technical application of fracture mechanics to thin-walled structures

This paper reviews recent developments in the application of fracture mechanics to such structures as welded steel tanks, ships, and thin-wall pressure vessels, with particular attention to Japanese work. It describes methods for estimating critical crack size and safe working conditions, taking into account such fabrication variables as angular distortion, welding residual stress, prestrain, plate curvature and stress concentration. Whilst most of the paper is devoted to a consideration of the conditions for crack instability, it also discusses crack arrest and gives experimental results for the effect of thickness on both initiation and arrest.     

Electrochemiluminescence of 9,10-diphenylanthracene-halogen ion systems

Influence of halide ions (Cl^?, Br^?, I^?) on the electrochemiluminescence (ecl) of 9,10-diphenplanthracene (DPA) is studied by using controlled-potential double-step method. It is confirmed that the ecl begins to appear at the anodic potential corresponding to the potential of the first anodic half-wave potential of each halide ion and that, passing through an intensity maximum, it disappears at more positive potential. Similarly, when the cathodic potential is changed, the ecl appears at the first cathodic half-wave potential of DPA and disappears at more negative potential than the second half-wave potential of DPA. These facts indicate that the ecl must be due to the reaction between oxidised species of halide ions (presumably trihalide ions) and monovalent DPA anion radicals. The mechanism for the formation of the excited singlet state of DPA is reasonably explained by assuming a reaction scheme containing a mono-halogenated DPA radical as an intermediate.