Grain boundary misorientations were determined, by using electron back-scattering diffraction techniques, for Ta-encapsulated Cu interconnects which contained thermally stress-induced voids. The misorientation angles at voided and non-voided line segments were analyzed for 2 different heat treatments which led to different susceptibilities to stress voiding. Non-voided line segments contained a larger percentage of low-angle lower-diffusivity boundaries than did regions which were adjacent to voids. The more void-resistant samples also contained a generally higher proportion of low misorientation angle boundaries than did samples which exhibited greater voiding.

J.A.Nucci, R.R.Keller, D.P.Field, Y.Shacham-Diamand: Applied Physics Letters, 1997, 70[10], 1242-4