In　this　study,　the　interfacial　phase　evolution　during　Cu/Sn/Cu　soldering　(260　degrees　C,　1　N)　with　a　micro　interconnected　height　of　6　Inn　was　analyzed.　During　soldering,　the　Cu6Sn5　precipitated　first　along　Cu/Sn　interfaces　in　a　planar　shape.　After　the　appearance　of　Cu6Sn5,　the　Cu3Sn　emerged　between　Cu　and　Cu6Sn5　in　a　planar　shape　as　well.　Then,　until　residual　Sn　was　completely　consumed,　the　Cu6Sn5　layers　at　opposite　sides　continued　to　grow　with　a　change　from　the　planar　shape　to　a　scallop-like　shape.　In　the　meantime,　the　Cu3Sn　layers　continued　to　grow　with　a　round-trip　change　from　the　planar　shape　to　a　wave-like　shape.　After　the　total　consumption　of　residual　Sn,　the　Cu3Sn　grew　at　the　expense　of　Cu6Sn5　until　the　formation　of　full　Cu3Sn　solder　joints　at　300　min.　Further,　concrete　reasons　for　the　interesting　shape　change　in　both　Cu6Sn5　layers　and　Cu3Sn　layers　were　given.　With　the　soldering　time　increasing　from　10　min　to　60　min,　the　morphology　of　Cu6Sn5　grains　agreed　with　the　shape　of　Cu6Sn5　layers　well.　As　the　growth　of　Cu6Sn5,　a　ripening　process　without　the　dependence　on　the　morphology　of　Cu6Sn5　grains　occurred.　The　dependence　of　mean　radius　of　Cu6Sn5　grains　on　the　soldering　time　was　based　on　the　relation　of　R　=　C(1)t(k)　at　different　time　segments.　The　morphology　of　Cu6Sn5　grains　affected　Cu　flux,　leading　to　different　growth　mechanism　at　these　time　segments.　From　10　min　to　30　min,　the　constant　k　was　calculated　to　be　0.53,　which　was　due　to　the　growth　of　Cu6Sn5　being　only　supplied　by　the　interfacial　reaction　flux.　From　40　min　to　60　min,　the　constant　k　was　calculated　to　be　0.35,　which　was　due　to　the　growth　of　Cu6Sn5　being　supplied　by　both　the　interfacial　reaction　flux　and　the　ripening　flux.　Compared　with　the　growth　of　Cu6Sn5　grains　at　30　min,　the　growth　of　Cu6Sn5　grains　at　40　min　was　supplied　by　an　additional　Cu　flux　(the　ripening　flux),　which　led　to　the　constant　k　being　3.82　from　30　min　to　40　min.　Moreover,　the　growth　process　of　Cu6Sn5　grains　was　thought　to　be　the　accumulation　of　a　growth　period　of　＂formation　of　small　grains　on　the　surface　of　big　grains　growth　of　small　grains　along　the　preferential　growth　direction　of　corresponding　big　grains　-＞　mergence　of　small　grains　on　corresponding　big　grains　-＞　formation　of　new　big　grains　on　previous　big　grains　-＞　mergence　between　new　big　grains　and　previous　big　grains＂.