Herein,　it　was　investigated　the　growth　kinetics,　grain　orientation,　and　mechanical　properties　of　the　Cu20Sn6　phase　aged　from　full　Cu3Sn　joints　at　the　aging　temperatures　of　600,　620,　and　640　°C.　The　results　showed　that　the　growth　mechanism　of　the　Cu20Sn6　phase　was　dominated　by　bulk　diffusion.　Furthermore,　the　activation　energy　of　Q　and　the　growth　rate　constant　of　k0　were　respectively　45.25 kJ/mol　and　3.6　×　104　µm2/min　for　the　Cu20Sn6　phase.　Besides,　although　the　preferred　orientation　of　the　Cu20Sn6　was　not　very　obvious,　it　was　[0001]　direction　in　parallel　to　the　diffusion　direction.　And,　in　ND,　the　[010]Cu3Sn　was　parallel　to　the　[01–11]Cu20Sn6　and　[11–21]Cu20Sn6.　Based　on　the　nanoindentation　results,　the　average　hardness　of　Cu3Sn　and　Cu20Sn6　phase　was　approximately　7.12　±　0.12　GPa　and　8.69　±　0.47　GPa,　while　the　corresponding　Young’s　moduli　were　143.80　±　4.51　GPa　and　166.43　±　7.32　GPa.　Consequently,　the　Cu20Sn6　phase　had　a　better　performance　on　hardness　and　Young’s　moduli　than　Cu3Sn.　Last　but　not　least,　the　shearing　strength　for　the　soldering　joints　increased　from　35.71　to　60.77 MPa　with　increasing　aging　time.　The　fracture　mechanism　of　Cu3Sn　was　an　intergranular　fracture,　while　it　was　a　cleavage　fracture　for　Cu20Sn6.　Furthermore,　the　fracture　mechanism　presented　a　mixed　fracture　of　intergranular　and　transgranular　fracture　when　the　joints　consisted　of　Cu3Sn　and　Cu20Sn6.　©　2023,　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature.