Three-dimensional　(3D)　package　technology　is　currently　considered　as　one　of　the　best　solution　to　beyond　Moore＇s　Law　and　achieve　miniaturization,　high　density　and　multi-functional　of　the　device.　Copper　filled　in　through　silicon　via　(Cu-TSV)　technology　with　good　electrical　performance　and　high　reliability,　is　a　new　type　of　3D　packaging　technology.　Cu-TSV　has　been　widely　used　in　integrated　circuit　technology　due　to　its　excellent　interconnection　performance.　Residual　stress　could　be　generated　in　Cu-TSV　during　the　manufacturing　process　which　could　be　relaxed　by　annealing　treatment.　However,　the　Cu　protrusion　out　of　the　TSV　could　also　occurred　during　annealing　process　due　to　the　large　temperature　variation　and　the　severe　mismatch　of　thermal　expansion　coefficient　between　copper　(17.6×10-6/K)　and　silicon　(2.8×10-6/K).　This　could　be　a　potential　threat　to　reliability　of　the　back-end　interconnect　structure,　since　it　might　lead　to　cracking　or　even　failure　of　the　device.　In　this　paper,　the　TSV　samples　were　annealed　at　different　temperatures　and　times　to　study　the　protrusion　and　microstructure　of　the　copper.　The　heating　temperatures　were　250°C,　350　°C　and　450°Cwith　30min,　60min　and　90min,　respectively.　The　protrusion　behaviors　and　microstructure　of　different　samples　were　further　characterized　and　compared.　The　protrusion　behaviors　were　characterized　by　Focus　Ion　Beam　(FIB)　and　Confocal　Laser　Scanning　Microscope　(CLSM),　which　reveal　that　the　annealing　temperature　and　heating　time　have　a　significant　effect　on　the　protrusion.　With　the　annealing　temperature　and　time　increase,　the　protrusion　behavior　becomes　more　and　more　obvious,　however,　the　annealing　time　has　little　effect　than　annealing　temperature　on　the　protrusion.　The　cross　section　microstructure　of　TSV　was　also　studied　by　Electron　Backscatter　Diffraction　(EBSD).　The　results　showed　that　the　Cu　grain　size　of　all　specimen　increases　but　the　grain　orientation　no　significant　changes　after　annealing.　The　grain　size　is　positive　correlation　to　the　annealing　temperature.　The　residual　stress　in　Cu　and　Si　around　the　TSV　was　measured　using　Raman　spectrometer.　This　work　could　help　to　find　out　the　optimized　annealing　condition　which　could　further　improve　the　reliability　of　TSV　structure.　©　2017　IEEE.