The　morphological　evolution　and　grain　orientations　of　intermetallic　compounds　(IMCs)　were　investigated　during　the　formation　of　full　Cu3Sn　joints　at　two　soldering　temperatures　(310　and　430　degrees　C).　The　mechanical　properties　of　both　types　of　full　Cu3Sn　joints　were　then　analyzed.　The　experimental　results　showed　that　the　morphology　of　interfacial　IMCs　varied　significantly　at　two　temperatures.　At　310　degrees　C,　scallop-like　Cu6Sn5　grains　became　larger　but　were　fewer　in　number　and　the　top　of　the　scallops　became　rough　due　to　the　grain　ripening　effect.　With　the　increase　in　the　soldering　temperature　to　430　degrees　C,　Cu3Sn　no　longer　grew　uniformly　as　observed　during　soldering　at　310　degrees　C,　but　exhibited　various　growth　rates.　Furthermore,　some　eta-Cu6Sn5　transformed　into　eta＇-Cu6Sn5　during　cooling,　and　the　following　orientation　groups　between　eta＇-Cu6Sn5　and　eta-Cu6Sn5,　i.e.,　{102}eta＇　and　{1120}eta,　{112}eta＇　and　{1010}eta,　and　{201}eta＇　and　{0001}eta,　were　found　to　be　near-parallel.　The　Cu3Sn　grains　were　preferably　oriented　with　[203]　and　[100]　crystal　orientations　parallel　to　transverse　direction　(TD)　at　both　temperatures.　Noteworthy,　the　Cu3Sn　grains　with　[203]//TD　and　[010]//ND　grew　much　faster　than　those　with　other　orientations　at　430　degrees　C.　Moreover,　molecular　dynamics　simulation　showed　that　the　diffusion　coefficients　of　atoms　in　Cu3Sn　crystals　along　[203]　direction　were　significantly　greater　than　those　in　other　low-index　crystal　directions.　After　soldering,　two　types　of　full　Cu3Sn　joints　obtained　at　different　temperatures　exhibited　different　shear　strength　and　fracture　mechanisms.