SUMMARIES OF THE 1996 OUTSTANDING UNDERGRADUATE AND GRADUATE PAPERS

Brazing Titanium Beta Alloys

X-Ray Microdiffraction for VLSI

This paper describes how x-ray microbeam diffraction is being used to measure strain with micrometer-scale spatial resolution. Micrometer-scale x-ray beams can be obtained using tapered glass capillaries. With the high brightness and broad energy spectrum of synchrotron radiation and the energy dispersive capabilities of commercially available liquid-nitrogen cooled x-ray detectors, spatially resolved strains in a sample can be determined along different directions without having to rotate the sample, in contrast with more conventional methods using monochromatic x-ray diffraction. This is a major advantage in achieving micrometer-scale spatial resolution. Strain sensitivities on the order of 2 x 10⁷ have been achieved.

White beam x-ray microdiffraction has been applied for the first time in real-time studies of thermal- and electromigration-related strain distributions in passivated aluminum-on-silicon conductor lines. Results of measurements on a single 10 µm wide line are described.
--P.C. Wang