To　investigate　the　protrusion　behavior　of　the　copper　filled　in　through　silicon　via　(TSV),　four　sets　of　TSV　copper　samples　are　prepared　by　using　four　level　sets　of　electroplating　current　density　and　additive　concentration,　and　then　the　samples　are　annealed　with　three　temperature　ramp　rates,　10　degrees　C/min,　1.2　degrees　C/min　and　0.6　degrees　C/min,　respectively.　Protrusion　of　the　copper　in　all　of　the　samples　after　annealing　is　measured,　and　the　grain　size　of　the　copper　before　and　after　annealing　is　examined.　A　mechanism　of　grain　size　evolution　is　developed　to　explain　the　protrusion　process　during　annealing.　A　finite　element　(FE)　model　is　also　built　up　and　a　grain　size　dependent　material　model　is　introduced　to　explain　the　effects　of　electroplating　parameter　and　annealing　temperature　ramp　rate.　Experimental　and　numerical　results　show　that　the　sample　filled　by　higher　electroplating　current　density　and　higher　additive　concentration　has　smaller　copper　grain　size　both　before　and　after　annealing,　and　also　has　less　protrusion.　The　protrusion　strongly　depends　on　the　grain　size　both　before　and　after　annealing.　The　annealing　temperature　ramp　rate　has　significant　impact　on　the　grain　size　and　protrusion　after　annealing.　The　temperature　ramp　rate　affects　the　protrusion　by　influencing　grain　size　evolution　process,　and　the　mechanism　is　also　validated　by　FE　analysis.　After　all,　an　optimized　annealing　temperature　profile　is　proposed　to　minimize　the　copper　protrusion　by　restraining　the　growth　of　grain　during　annealing.　(C)　2016　Elsevier　Ltd.　All　rights　reserved.