界面密排六方固溶体提高Au-Ge/Cu焊点的剪切强度

Formation of ductile close-packed hexagonal solid solution on improving shear strength of Au−Ge/Cu soldering joint

系统研究界面产物形貌、化学成分、力学性能及其对Au−Ge/Cu焊点剪切强度的影响。结果表明,在400℃下钎焊5~60 min后,焊点界面生成密排六方结构固溶体相(HCP)。该HCP相成分为78%~46%Cu,9%~42%Au和~12%Ge(摩尔分数),杨氏模量为105~112 GPa,硬度为4.3~4.7 GPa。钎焊5 min焊点的剪切强度为57 MPa,但钎焊60 min后焊点的剪切强度上升至68 MPa。焊点强度的提高可归因于塑性HCP相的生成及其对脆性(Ge)相的消耗。这说明生成塑性HCP界面产物是一种能有效提高钎焊焊点剪切强度的方法。

The morphology,chemical composition,mechanical properties of the interface reaction products and their effects on the shear strength of the Au−Ge/Cu soldering joint were systematically investigated.The results showed that a close-packed hexagonal(HCP)structure solid solution phase was formed at the interface after soldering at 400℃ for 5−60 min.The composition of the HCP phase varied among 78−46 at.%Cu,9−42 at.%Au and~12 at.%Ge.The Young’s modulus and hardness of HCP phase were 105−112 GPa and 4.3−4.7 GPa,respectively.The shear strength of the 5 min soldering joint was 57 MPa;however,it increased to 68 MPa when the soldering time was prolonged to 60 min.The increasing shear strength can be ascribed to the formation of HCP ductile phase and its effect on depleting the brittle(Ge)phase.It suggested that a HCP structured solid solution formed at the interface could enhance the shear strength of the solder joint.