【摘要】 采用扫描电镜与能谱测试,研究了两种不同印刷电路板铜面保护层,即有机保护层(OrganicSolderabilityPreservatives,OSP)与浸银层(ImmersionAg,I-Ag),对无铅焊点结构的影响。结果显示,采用有机保护层的焊接界面金属间化合物层厚度明显超过了浸银层;在两种不同保护层中的焊点中,均出现薄片状或树枝状Ag3Sn金属间化合物,但在浸银层焊点中,薄片状Ag3Sn主要在焊接界面层处非均匀形核长大,而有机保护层焊点中,薄片状Ag3Sn较少出现,代之以树枝状Ag3Sn近似均匀地分布在焊点中。断口分析显示,采用有机保护层的焊点中出现了较多的气孔,而且气孔主要出现在靠近铜面焊点中,这明显降低了焊点的强度。更多还原

【Abstract】 Effect of Cu surface finishes,including organic solderability preservatives （OSP） and immersion Ag （I-Ag）,on the microstructure of lead-free solder joint was investigated with scanning electron microscope and energy dispersive X-ray spectroscopy).It was found that Cu surface finishes affected the microstructure of lead-free solder joint.The thickness of intermetallic compounds （IMC） layer with OSP was higher than that of I-Ag.Comparing with OSP,there are more plate-like Ag₃Sn intermetallic compounds between solder joints and Cu pad after I-Ag surface finishing.However,there are more voids found in the solder joints which distributed close to the solder interface and reduced the strength of solder joints after OSP surface finishing.更多还原