Thermal　fatigue　failure,　due　to　the　fracture　of　solder　joints　which　was　cased　by　the　mismatch　deformation,　is　frequently　encountered　in　flip　chip　assemblies.　Unfortunately,　there　is　no　widely　accepted　method　to　evaluate　the　reliability　of　solder　joints,　especially　for　lead-free　solder　joints,　in　such　assemblies　up　to　now.　The　constitutive　models　of　double　power　law　and　the　hyperbolic　sine　law　were　implemented　to　simulate　the　deformation　of　SnAgCu　solder　joints　in　flip　chip　assemblies　in　this　paper.　The　accumulated　creep　strain　and　accumulated　creep　strain　energy　density　of　the　solder　joints　were　calculated,　via　finite　element　method,　and　were　used　to　predict　the　thermal　fatigue　life　of　flip　chip　assemblies.　The　applicability　of　the　above　life　prediction　methods　was　evaluated　through　cross　check　of　the　present　results　with　that　of　the　literatures.　It　was　found　that　the　life　of　the　FC　assemblies　could　be　estimated　by　the　prediction　of　the　life　of　the　corner　solderjoints.　The　thermal　fatigue　life,　estimated　by　accumulated　creep　strain　energy　density　is　closer　to　the　test　data　than　that　of　the　life　estimated　by　accumulated　creep　strain.　The　life　predicated　according　to　accumulated　creep　strain　shows　a　slightly　high　value　than　that　predicated　according　to　accumulated　creep　strain　energy　density.　The　double　power　law　constitutive　equation　results　in　higher　predicted　life.　(c)　2006　Published　by　Elsevier　B.V.