The　effects　of　the　intermetallic　compound　(IMC)　microstructure　and　the　strain　rate　on　the　tensile　strength　and　failure　mode　of　Pb-free　solder　joints　are　investigated.　The　samples　of　Sn3.0Ag0.5Cu/Cu　solder　joints　are　aged　isothermally　at　150　degrees　C　for　0,　72,　288　and　500　h,　and　the　thickness　of　the　IMC　layer　and　the　roughness　of　the　solder/IMC　interface　are　measured　and　used　to　characterize　the　microstructure　evolution　of　the　IMC　layer.　The　tensile　tests　of　the　aged　solder　joints　are　conducted　under　the　strain　rates　of　2　x　10(-4),　2　x　10(-2)　and　2　s(-1).　The　results　indicate　that　both　the　thickness　and　roughness　of　the　IMC　layer　have　influence　on　the　strength　and　failure　mode　of　the　solder　joint.　With　the　increase　of　the　aging　time,　the　thickness　of　the　IMC　layer　increases　and　the　roughness　of　the　solder/IMC　interface　decreases,　as　a　result,　the　tensile　strength　of　the　solder　joint　decreases　and　the　dominant　failure　mode　migrates　from　the　ductile　fracture　in　the　bulk　solder　to　the　brittle　fracture　in　the　IMC　layer.　There　is　a　positive　correlation　between　the　tensile　strength　of　the　solder　joint　and　the　stain　rate　applied　during　the　test.　With　the　increase　of　the　strain　rate,　the　failure　mode　migrates　from　the　ductile　fracture　in　the　bulk　solder　to　the　brittle　fracture　in　the　IMC　layer.　(c)　2014　The　Authors.　Published　by　Elsevier　Ltd.　All　rights　reserved.