Current　densities　of　1.5ASD　and　additive　concentrations　of　15ml/L　were　used　to　electroplate　the　copper　into　TSV　to　fabricate　the　test　samples.　The　samples　were　annealed　at　425°C　for　30　minutes　in　a　vacuum　furnace　with　the　heating　rate　of　10°C　/min.　The　annealed　samples　were　thermal　cycled　with　temperature　range　(25∼325°C),　heating　&　cooling　rate　(10　°C/min),　dwell　time　of　2　min　at　the　peak　and　bottom　temperature　in　each　cycle.　The　copper　protrusion　and　microstructure　evolution　are　examined　during　the　thermal　cycling.　The　results　show　that,　the　protrusion　value　increases　gradually　with　the　thermal　cycling　number　increases,　and　reaches　stable　value　of　2.152μm　after　the　cycling　number　increases　to　30　cycles.　The　average　copper　grain　size　grows　larger　as　the　thermal　cycling　number　accumulates,　suggesting　grain　growth　occurs　during　the　thermal　cycling.　The　sample　with　greater　copper　grain　size　has　a　greater　protrusion　after　the　thermal　cycling　test.　©　2016　IEEE.