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利用差示扫描量热分析法结合焊点回流过程,研究了无Pb钎料Sn-3.5Ag与Cu基底构成的Sn-3.5Ag/Cu体系模拟焊点中早期界面反应及焊点形成过程中钎料熔化和凝固特性.结果表明,加热过程中Cu向钎料合金侧的固态原子扩散导致界面生成低熔点Sn-Ag-Cu三元合金,使焊点界面在低于Sn-3.5Ag钎料熔点温度近4℃时即开始熔化;早期界面反应促使润湿过程提早发生并生成了一定厚度的扇贝状Cu-Sn型金属间化合物(IMC),原体系转变为Sn-Ag-Cu/Cu体系;转变后的焊点体系在IMC的非均匀形核作用下具有较低的过冷度.
Using differential scanning calorimetry and solder reflow process, the effects of Sn-3.5Ag / Cu Sn-3.5Ag / Cu solder joints on the early interface reaction and solder joint formation The results show that the diffusion of Cu to the solid-state atoms on the solder alloy side during heating results in the formation of a low-melting Sn-Ag-Cu ternary alloy at a temperature below the melting point of the Sn-3.5Ag solder When the temperature was near 4 ℃, the melting began. The early interfacial reaction promoted the premature wetting process and produced a certain thickness of scallop Cu-Sn intermetallic compound (IMC). The original system was changed to Sn-Ag-Cu / Cu system. After the transformation of the solder joint system in the IMC heterogeneous nucleation has a lower degree of undercooling.