Microstructural characterization of inlaid copper interconnect lines

The microstructure of inlaid Cu lines has been quantified as a function of annealing conditions, post-plating, and post-CMP. The grain size distribution was measured using the median intercept method, crystallographic texture was characterized by pole figure analysis, and mechanical stress was determined using x-ray diffraction. The median grain size and mechanical stress level increase with increasing anneal temperature. The crystallographic texture is independent of the anneal temperature and is predominantly (111) with a small fraction of sidewall-nucleated (111) grains. The (111) grains nucleated from the trench bottom have a preferred in-plane orientation. The grain growth in the trench is independent of that in the overburden.     

A framework for preprocessor‐aware C source code analyses

Analyses of C source code usually ignore the C preprocessor because of its complexity. Instead, these analyses either define their own approximate parser or scanner, or else they require that their input already be preprocessed. Neither approach is entirely satisfactory: the first gives up accuracy (or incurs large implementation costs), while the second loses the preprocessor‐based abstractions. We describe a framework that permits analyses to be expressed in terms of both preprocessing and parsing actions, allowing the implementer to focus on the analysis. We discuss an implementation of such a framework that embeds a C preprocessor, a parser, and a Perl interpreter for the action ‘hooks’. Many common software engineering analyses can be written surprisingly easily using our implementation, replacing numerous ad‐hoc tools. The framework's integration of the preprocessor and the parser further enables some analyses that otherwise would be especially difficult to perform. Copyright © 2000 John Wiley & Sons, Ltd.     

Extruded starch–nanoclay nanocomposites: Effects of glycerol and nanoclay concentration

Wheat starch‐Cloisite Na+ nanoclay composites containing different glycerol and nanoclay concentrations were extruded using a twin‐screw extruder. X‐ray diffraction and transmission electron microscopy were used to determine the extent of nanoclay dispersion and thermogravimetric analysis was used to characterize thermal stability of composites. Also, water absorbance was measured for each sample. The extent of nanoclay dispersion in samples containing 47 wt% total plasticizer concentration depended on glycerol concentration. For these samples, adding 5 wt% glycerol produced mostly exfoliated nanoclay, whereas adding 10 or 15 wt% glycerol produced intercalated nanoclay. Also, nanoclay composites exhibited improved thermal stability and reduced water uptake compared to samples with no nanoclay. However, thermal stability and water absorbance were not affected by the extent of nanoclay dispersion. POLYM. ENG. SCI., 47:1898–1904, 2007. © 2007 Society of Plastics Engineers     

Quantitative secondary ion mass spectrometry imaging of self-assembled monolayer films for electron beam dose mapping in the environmental scanning electron microscope

Fluorinated alkanethiol self-assembled monolayers (SAM) films immobilized on gold substrates have been used as electron-sensitive resists to map quantitatively the spatial distribution of the primary electronbeam scattering in an environmental scanning electron microscope (ESEM). In this procedure, a series of electron dose standards are prepared by exposing a SAM film to electron bombardment in well-defined regions at different levels of electron dose. Microbeam secondary ion mass spectrometry (SIMS) using Cs⁺ bombardment is then used to image the F^- secondary ion signal from these areas. From the reduction in F^- intensity as a function of increasing electron dose, a calibration curve is generated that allows conversion of secondary ion signal to electron dose on a pixel-by-pixel basis. Using this calibration, electron dose images can be prepared that quantitatively map the electron scattering distribution in the ESEM with micrometer spatial resolution. The SIMS imaging technique may also be used to explore other aspects of electron-surface interactions in the ESEM.     

Monte Carlo simulations of microchannel plate detectors. II. Pulsed voltage results

This paper is the second part of a continuing study of straight-channel microchannel plate (MCP)-based x-ray detectors. Such detectors are a useful diagnostic tool for two-dimensional, time-resolved imaging and time-resolved x-ray spectroscopy. To interpret the data from such detectors, it is critical to develop a better understanding of the behavior of MCPs biased with subnanosecond voltage pulses. The subject of this paper is a Monte Carlo computer code that simulates the electron cascade in a MCP channel under an arbitrary pulsed voltage, particularly those pulses with widths comparable to the transit time of the electron cascade in the MCP under DC voltage bias. We use this code to study the gain as a function of time (also called the gate profile or optical gate) for various voltage pulse shapes, including pulses measured along the MCP. In addition, experimental data of MCP behavior in pulsed mode are obtained with a short-pulse UV laser. Comparisons between the simulations and experimental data show excellent agreement for both the gate profile and the peak relative sensitivity along the MCP strips. We report that the dependence of relative gain on peak voltage is larger in pulsed mode when the width of the high-voltage waveform is smaller than the transit time of cascading electrons in the MCP.     

Tools and procedures for quantitative microbeam isotope ratio imaging by secondary ion mass spectrometry

In this work we demonstrate the use of secondary ion mass spectrometry (SIMS) combined with the Lispix image processing program (Bright 1995) to generate quantitative isotope ratio images from a test sample of a calcium-aluminum rich inclusion from the Allende meteorite that is known to contain discrete mineral grains with perturbed Mg isotopic ratios. Using 19.5 keV impact O- primary ion bombardment and detection of positive secondary ions, microbeam imaging SIMS has allowed us to identify, from the isotope ratio images, enrichments in the 26Mg/24Mg isotope ratio of approximately 5-15% in selected mineral grains. Using custom image processing software, each isotopic ratio image is corrected on an individual pixel basis for a number of factors including detector dead-time, mass bias effects, and isobaric interferences. We have developed procedures for correlating the isotopic images with polarized optical microscopy so that targeted mineral grains could be identified for further SIMS analysis. Finally, additional image processing tools have been developed to allow for pixel-by-pixel evaluation of the influence of detector dead-time and count rate errors on the isotopic ratio images and for correlation of the isotopic images with elemental distribution maps.     

Statistical basis for predicting the need for bacterially induced beach closures: Emergence of a paradigm?

Data collected from four beaches along southern Lake Michigan (USA) during the summer of 2004 were subjected to correlation and time-series regression analyses aimed at identifying an optimal suite of variables that could be used to predict log Escherichia coli concentrations in real time. Although other variables entered into the regression equations, waves, outfalls of bacteria from an adjacent stream, sunshine, temperature, and time of day (morning versus afternoon) turned out to be the most useful and consistent predictive variables. A post-hoc analysis showed that regression models are much more successful than previous day's bacterial concentration at predicting whether or not the beach water quality is above or below the threshold criteria for full body contact established by the USEPA. Additional analyses, using 99% confidence intervals on predicted log E. coli concentrations, indicated that in extreme cases of high or low health threat, model predictions are likely to be accurate about 90% of the time. The findings of this study are consistent with previous work in the region and seem to indicate that real-time monitoring of hydrometeorological variables can provide the basis of an early warning system for protecting the public from the health risk posed by harmful pathogens in beach water.     

Notes on Contributors

The development of the one stop shop approach is seen as a means to providing a customer focused planning service. Research in England and Scotland, for example, suggests a tendency to the emergence of a common 'one stop shop' approach in terms of an administrative model with defined responsibilities and relations between those departments involved in the planning and development service. This article reviews the research evidence about the effectiveness of the 'one stop shop' approach to integrated planning and development functions. It reports on the nature of emerging arrangements for securing such an integrated approach in the interests of planning customers. The article suggests there are advantages to this form of planning service.     

A note on mercury levels in the hair of Alaskan reindeer

Reindeer, as terrestrial herbivores, generally have low levels of Hg, but monitoring Hg levels can help in understanding ecological toxicity related to a changing environment. In this study, Alaskan reindeer were analyzed for total mercury (THg) in their hair. Both free-ranging reindeer from the Seward Peninsula, Alaska and reindeer fed a pollock-based fishmeal diet were surveyed. Free ranging reindeer had mean THg levels of (55.3 ng/g; n=5). The mean MeHg level in the free ranging reindeer was 45.5 (ng/g; n=5) or 79% of the THg level. The mean level for THg in the fishmeal fed reindeer was 19 ng/g (n=10). Younger reindeer (2 years of age or less) showed lower levels (0.8 ng/g, n=2) compared to adult reindeer (30.8 ng/g, n=6).     

Urban Form and Housing Density,Australian Cities and European Models: Copenhagen and Stockholm Reconsidered

Stockholm and Copenhagen have been widely regarded in English-speaking countries as exemplifying aspects of the compact city—from well planned, mixed use, higher density, transit-oriented development to sociable urban spaces. So how is it that the development of these two cities has also been located in the garden city tradition? This article tackles this question in the context of the implications European cities are often thought to have for low-density Australian cities. Comparisons of the urban form of Stockholm and Brisbane and of higher density housing in Copenhagen and Brisbane emphasise that the ‘Scandinavian model’ is as much about the role of open space in shaping urban form and in housing design as our current preoccupation with density.