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This paper examines the mechanics of ball shear testing with the objective of understanding the mechanism by which the maximum shear force and the rate of crack growth is dependent on the solder bump size. For this, Pb-Sn solder bumps with diameters between 460 μm and 760 μm are soldered to 400 μm-diameter Cu pads and subjected to ball shear testing. In spite of the constant interface area, the bump size significantly impacts the measured shear fracture force and the crack growth rate. Both the fracture force and the crack growth rate increase with bump size, and in the case of the fracture force, the increase is almost linear. Our analysis finds that the linear increase in the fracture force is a result of the bump deformation force, which increases with bump size. A simple model that accounts for the deformation force component is developed and used to extract the true interface fracture force. The estimated true interface fracture force is found to vary little with bump size, tightly converging to the 40 MPa to 48 MPa range. On the other hand, the dependence of crack growth rate on bump size is found to result from the higher degree of rotational moment associated with larger bumps. [ABSTRACT FROM AUTHOR]

Devices in which the transport and storage of single electrons are systematically controlled could lead to a new generation of nanoscale devices and sensors. The attractive features of these devices include operation at extremely low power, scalability to the sub-nanometre regime and extremely high charge sensitivity. However, the fabrication of single-electron devices requires nanoscale geometrical control, which has limited their fabrication to small numbers of devices at a time, significantly restricting their implementation in practical devices. Here we report the parallel fabrication of single-electron devices, which results in multiple, individually addressable, single-electron devices that operate at room temperature. This was made possible using CMOS fabrication technology and implementing self-alignment of the source and drain electrodes, which are vertically separated by thin dielectric films. We demonstrate clear Coulomb staircase/blockade and Coulomb oscillations at room temperature and also at low temperatures. [ABSTRACT FROM AUTHOR]

The electrochemical mechanism behind voltammograms produced by defective barriers in low-k/Cu interconnect structures is investigated using simulation cells which mimic various barrier conditions. The findings reveal that the Cu reaction peak current used as an indicator for barrier defects represents oxidation of Cu at the anodic electrode. When both electrodes have similar defect (Cu) fraction, the voltammogram is symmetric, but when the electrodes have different Cu fraction, the voltammogram is asymmetric and changes during repeated cycling until a stable form is reached. [ABSTRACT FROM AUTHOR]

The author looks at several articles about the use of thin film materials for solar cell and biosensor applications, published in the December 2007 issue of the periodical "JOM." He cites that better utilization of solar technology could potentially resolve many problems such global warming. He cites that the articles about solar cells for extra-terrestrial applications will shape the future of solar cells in commercial applications. He notes that the paper on bionsensors asks readers to change their perception about biotechnology.

Presents information on a symposium on "Challenges in Advanced Thin Films: Microstructures, Interfaces and Reactions" held in Charlotte, North Carolina from March 14-18, 2004. Sponsors of the symposium; Symposium attendees.