The　electron　backscatter　diffraction　technique　(EBSD)　has　been　used　to　measure　the　microstructure　of　reactive　ion　etched　(RIE)　AI　and　damascene　Cu　interconnects,　including　the　grain　size,　grain　orientation　and　grain　boundary　characteristics.　Linewidths　of　Cu　interconnects,　as　well　as　the　anneal　processes　of　Al　and　Cu　interconnects　impacting　on　the　microstructures　and　causing　the　electromigration　failure　were　analyzed.