光纤定位激光钎焊键合过程中钎料与镀层的界面反应

Interfacial reaction between solder alloys and metallization during laser solder bonding process for optical fiber alignment

光电子封装中,光导纤维的定位键合是一项关键技术,并且焊点界面处的显微组织对于焊点的可靠性有重要影响.本文选用80Au20Sn和52In48Sn钎料实现了激光钎焊条件下的光纤键合,采用扫描电子显微镜及能谱分析的方法对于两种钎料分别与硅片上的Au/Ti镀层和光纤上的Au/Ni镀层反应形成的界面微观组织形态及形成规律进行了分析.结果表明:对于80Au20Sn钎料,除了共晶组织ζ相+δ相,在AuSn/Au/Ti镀层界面形成了大量枝状的先共晶ζ相,在AuSn/Au/Ni镀层界面形成了针状的(Au,Ni)3Sn2;对于52In48Sn钎料,在InSn/Au/Ti镀层界面形成了连续层状的Au(In,Sn)2,随着输入能量的增加,其逐渐转变为不连续的块状化合物AuIn2,在熔融钎料流的作用下部分AuIn2脱离界面进入钎料中,在InSn/Au/Ni镀层界面形成了一层极薄的Au(In,Sn)2.

Optical fiber bonding is a key technique in optoelectronic packaging, and the interfacial microstruc-ture has a significant influence on solder joint reliability. In this work, 80Au20Sn and 52In48Sn solders were chosen for fiber bonding through laser soldering, and a scanning electronic microscope （SEM） equipped with energy dispersiVe X -ray detector （EDX） was used to investigate the morphology and formation of microstruc-ture at four interfaces between two solders and two metallizations： AuSn/（Au/Ti） , AuSn/（Au/Ni）, InSn/ （Au./Ti） and Insn/（Au/Ni）. Results show that a large amount of dendritic pre -eutectic ξ -phase forms at the AuSn/（ Au/Ti ） interface, while some needle - like （ Au, Ni） 3 Sn2 forms at the AuSn/（Au/Ni） interface, an obviously continuous Au （In, Sn）2layer forms at the InSn/（Au./Ti） interface and an extremely thin Au （In, Sn） 2layer forms at the InSn/（Au/Ni） interface. Moreover, the continuous Au（In,Sn）2 layer transforms into incontinuous block - like Auln2 at the InSn/（Au/Ti） interface with the increase of input laser energy.