X-Ray Microdiffraction for VLSI

Abstract

AbstractWe describe how x-ray microbeam diffraction is being used to measure strain with micronscale spatial resolution. Micron-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 micron-scale spatial resolution. Strain sensitivities on the order of 2×10−4 have been achieved in such measurements. 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 Al-on-Si conductor lines. Results of measurements on a single 10μm-wide line are described.