X-ray microdiffraction study of Cu interconnects

We have used x-ray microdiffraction to study the local structure and strain variation of copper interconnects. Different types of local microstructure s have been found in different samples. Our data show that the Ti adhesion layer has a very dramatic effect on Cu microstructure. Strain measurement w as conducted before and after electromigration test, Cu fluorescence was us ed to find the mass variations around voids and hillocks, and x-ray microdi ffraction was used to measure the strain change around that interested regi on. (C) 2000 American Institute of Physics. [S0003-6951(00)03903-6].