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采用有Pb焊料对无Pb焊点球栅阵列(BGA)塑封器件进行焊接,选用再流焊工艺对器件进行混装焊接.对混装再流焊BGA器件分别进行4,9,16和25 d的高温老化实验,在老化实验前后不同阶段,使用精密电阻仪对混装BGA器件进行电性能测试,没有发现器件的电性能失效.利用SEM对焊点微观组织的分析发现,混装焊点印制电路板(PCB)侧金属间化合物(IMC)成分为Cu_3Sn和Cu_6Sn_5,BGA焊盘侧IMC成分为Ni-Cu-Sn三元化合物.对焊点两侧的IMC进行厚度测量,结果表明,随老化时间延长两侧的IMC厚度都增大,PCB一侧IMC生长速率明显高于BGA焊盘一侧.此外,有一些焊点内部和界面处出现了富Pb相聚集、IMC破裂、界面裂纹以及空洞等可靠性隐患.
Lead-free solder ball grid array (BGA) plastic encapsulated devices were soldered by using Pb solder, and the reflow soldering process was used to carry out the hybrid soldering of the devices. The mixed reflow soldering BGA devices were respectively subjected to 4, 9, 16 and 25 d , The electrical properties of the hybrid BGA devices were tested using a precision electrical resistance meter at different stages before and after the aging experiment.Analysis of the microstructures of the solder joints by SEM showed that the hybrid solder joint printing The IMC component of the circuit board (PCB) is Cu_3Sn and Cu_6Sn_5, and the IMC component of the BGA pad side is Ni-Cu-Sn ternary compound.The thickness of IMC on both sides of the solder joint is measured.The results show that The IMC thickness increased on both sides of the aging time, and the growth rate of IMC on the PCB side was obviously higher than that on the BGA side. In addition, some Pb-rich aggregates, IMC ruptures, interfacial cracks and Empty holes and other hidden dangers.