Growth behavior of Sn-Ag-Cu/Cu intermetallic compounds in high silver series
[Objective]The interfacial reaction and growth kinetics of high silver series Sn-Ag-Cu during solid phase aging were studied.[Methods]The effects of different silver contents on the interfacial structure and interfacial growth at high temperature were investigated experimentally and numerically.In order to determine the long-term reliability of solder joints,thermal accelerated aging tests were carried out at 150℃ for 0 h,100 h,300 h,500 h.The surface morphology,thickness and elemental composition of IMC were investigated by SEM and EDS.[Results]The results showed that the growth of Cu6Sn5 was inhibited with the increase of silver content.In the isothermal aging process,the growth kinetics of intermetallic compounds(IMC,Cu6Sn5+Cu3Sn)is a diffusion control process.Cu6Sn5 gradually grows into Cu3Sn.In the later aging stage,the scallop-like shape disappears,indicating that the growth mechanism has changed,and the change is stable growth in the direction vertical to the interface.Through the finite element technique,it is concluded that the thermal stress is mainly concentrated at the junction of Cu3Sn and Cu substrate during service.With the increase of aging time,the equivalent creep strain of solder joint rises and the reliability decreases gradually.The apparent activation energies of intermetallic compound IMC(Cu6Sn5+Cu3Sn)at the interface Sn-3.0Ag-0.7 Cu/Cu,Sn-3.4Ag-0.7Cu/Cu and Sn-3.8Ag-0.7Cu/Cu are 67.13 kJ/mol,70.50 kJ/mol,69.54 kJ/mol.[Conclusion]Respectively,according to arrinius formula,Sn-3.4Ag-0.7Cu/Cu is better than other solder joint components to meet the requirements of electronic components.
Sn-Ag-Cuinterface growthisothermal agingthickness of IMC
NETL
NSTL
万方数据
