Using　a　constant　load　compression　test,　the　creep　deformation　of　63Sn37Pb　solder　balls　was　studied　in　the　load　range　0.5-2　N　and　in　the　temperature　range　25-150　degrees　C.　There　was　no　steady-state　creep　due　to　continuous　changes　in　the　contact　area,　which　resulted　in　a　decrease　in　the　contact　stress.　Assuming　that　the　compression　velocity　was　proportional　to　the　uniaxial　strain　rate　and　the　contact　stress　was　proportional　to　the　uniaxial　stress　for　a　contact　radius　less　than　0.3　of　the　ball　diameter,　a　power　law　relationship　was　developed　between　the　compression　velocity　and　the　contact　area　for　constant　load　compression　creep　during　quasi-steady-state　creep.　The　finite　element　method　was　used　to　simulate　compression　creep　of　the　solder　ball　with　a　power　law　relation　between　uniaxial　stress　and　strain.　The　simulation　results　showed　that　the　nominal　stress　exponent　obtained　from　compression　creep　was　0.61　of　the　stress　exponent　obtained　from　uniaxial　creep.　Using　this　relationship,　we　obtained　a　stress　exponent　of　1.93-4.21　and　activation　energy　of　47.9-72.6　kJ　mol(-1)　for　the　compression　creep　of　63Sn37Pb　solder　balls.　(C)　2011　Acta　Materialia　Inc.　Published　by　Elsevier　Ltd.　All　rights　reserved.