As interconnect technology moves deeper into the submicron realm, the physics governing the mechanical behavior, hence the reliability of metal lines changes. Events at the level of individual grains become more important. One would like to be able to measure the strain and orientation of single grains, and the distribution of strain across a grain. Such data may help us understand such effects as sunken grains, the erratic occurrence of stress voiding and Blechlength effects in electromigration. To get this information, techniques involving X-ray diffraction with submicron beams are being developed. These experiments involve detecting Laue spots from selected areas and energy-analyzing them to find the strain tensor. Motivations for such measurements, the specifications for a useful instrument, some designs now being developed and the intrinsic limitations of these approaches will be discussed. Design issues in the choice of focussing optics and energy measurement will be highlighted with calculations of how the Laue spots would look for different conditions of crystal perfection.