回流时间对Sn0.3Ag0.7Cu/Cu焊点界面金属间化合物生长行为的影响

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Abstract： Cu/Sn0.3Ag0.7Cu/Cu composite solder joints were prepared by transient liquid phase diffusion bonding process.The effects of reflow time on the microstructure and growth kinetics of intermetalic compounds at the interface of Sn0.3Ag0.7Cu/Cu solder joints were studied by scanning electron microscopy and energy dispersive spectroscopy. The results show that the thickness of intermetallic compound （IMC）at the interface of Sn0.3Ag0.7Cu/

Cu solder joint is positively correlated with the reflux time when the reflux temperature is constant.With the increase of reflux time，the thickness of IMC layer in Cu/Sn0.3Ag0.7Cu/Cu solder joint increases gradually，and the morphology of itermetallccompound insolder jointchanges from serrated toscalloped.When the reflow time is 12h，theIMC grow together atthe hotandcold ends.Thecomplete reactionofSn elementin the solder matrix leads to the transformation of Cu6Sn5 phase into Cu3Sn phase，and the volume shrinkage caused by the phase transformation causes defects in the weld.The growth rateof IMCat thecold end is greater than that at the hot end.The diffusion coefficients of IMC at the cold and hot ends are 0.568μm2/h and 0.019μm2/h ，respectively. The growth of the cold end IMC is in the reaction control stage，the growth of the IMC is affected by the diffusion rate of Cu atoms，and the growth of the hot end IMC is controlled by grain boundary diffusion.The growth of IMC is affected by the rate of Cu （204 atoms passing through the grain boundary，and thegrowth is extremely slow.The shear strength of the welded joint wasreduced from 34.54MPa to 20.99MPa ，whichwasreduced by 39.2%

Keywords： intermetalic compounds；microstructure； transient liquid phase diffusion welding；solder joint

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