本研究利用同步輻射X光說明錫導線在電遷移效應下的臨場應力分佈，藉由高強度的X光可準確地測量微小的應力變化。可直接地測量電遷移效應所造成的背向應力，也可估算不同電流密度下的有效擴散係數。觀察焦耳熱效應且計算焦耳熱所造成的溫度增加量。考慮表面上的堅硬氧化層對應力分佈及變化的嚴重影響。觀察電遷移效應後的試片表面微結構變化。 在100°C、電流密度為1×103 A/cm2下，電遷移效應所造成的應力梯度約為5.5 MPa/cm；電流密度為5×103 A/cm2下，電遷移效應所造成的應力梯度約為16.5 MPa/cm。在5×103 A/cm2下，焦耳熱效應所造成的溫度增高約15°C。在100°C、電流密度為1×103 A/cm2和5×103 A/cm2下，估算錫的有效擴散係數分別為7.16×10-14 m2/s和6.01×10-14 m2/s。在長期的電遷移下，陰極端有孔洞生成，陽極端有凸塊產生。 This investigation elucidates stress evolution in situ in tin strips under electromigration using synchrotron radiation X-ray. Minute variations in stress are measured precisely using intense X-rays. Back stress that is induced by electromigration was directly measured. The effective diffusivities at various current densities were calculated. The effect of Joule heating was observed and the increase in temperature was calculated. The protective oxide layer on the surfaces is considered to influence critically the kinetics of stress evolution. The morphology of tin strips after electromigration was observed. Electromigration induced stress gradients are about 5.5 MPa/cm with current density of 1×103 A/cm2 and 16.5 MPa/cm with current density of 5×103 A/cm2 at 100°C. The evaluate increases in temperature by Joule heating is approximately 15°C. The diffusivity of Sn with current density of 1×103 and 5×103 A/cm2 at 100°C has been calculated to be 6.01×10-14 and 6.01×10-14 m2/s. Voids form at the cathode and hillocks form at the anode in the prolonged test of electroigration.