摘要
通过Nd∶YAG激光重熔和热风二次重熔试验,得到了Sn3.5Ag和Sn3.0Ag0.5Cu无铅钎料球在Cu焊盘的钎料凸台。利用扫描电子显微镜分别分析了激光重熔和热风二次重熔后两种无铅钎料与铜焊盘界面反应及组织形貌,并对激光一次重熔无铅钎料凸台进行了剪切试验,观察了凸台的剪切断口。结果表明,在合适的激光功率和加热时间条件下能够获得成形良好的无铅钎料凸台,Sn3.5Ag和Sn3.0Ag0.5Cu两种无铅钎料与Cu焊盘所产生的界面化合物主要为Cu3Sn和Cu6Sn5,凸台界面反应组织形貌以及剪切承载力与激光功率和加热时间密切相关,而且激光重熔形成的界面化合物影响热风二次重熔界面的组织形貌。
An investigation has been carried out to compare the interface of Cu pad and Sn- 3.5Ag solder and Sn -3.0Ag -0. 5Cu solder during laser reflow and hot air convection reflow. Effects of processing parameters of laser reflow bumping on the evaluation of interfacial intermetallic compounds （IMC） and the shear strength were studied. The parameters including laser reflow time and power on the morphology of intermetallic compounds at solder/pad interface were studied by Scanning Electron Microscopy （SEM） and Energy Dispersive X -ray Spectrometer （EDX）. The results revealed that the morphology of the IMC was strongly influenced by laser input energy. The microstructure of IMC changed from a continuous layer into acicular phases and then become broken parts, with the increase of laser input energy. However, the laser input parameters had little effect on the shear strength ,which were definitely influenced by shear failure modes.
出处
《电子工艺技术》
2006年第5期249-255,共7页
Electronics Process Technology
基金
哈尔滨工业大学基金项目(项目编号:HIT.2003.50)
关键词
激光重熔
BGA
无铅
金属间化合物
Intermetallic compounds
Lead - free
Laser reflow bumping
Hot air reflow bumping
