Electroless Ni-P-ZrO2 metallization for lead-free solder interconnection
Lead-free solder alloy is popular in electronic industry due to its environmental friendly characteristic.However,the interfacial reaction faces the thermal challenge caused by the increased melting temperature of lead-free solder alloy.In the present work,a composite Ni-P-ZrO2(15 at.%of P)layer was developed by electroless plating as novel under bump metallization(UBM).In order to homogeneously disperse ZrO2 nanoparticle in the Ni-P layer,ultrasonic vibration and magnetic stirring were adopted.The interfacial reaction between electroless Ni–P–ZrO2 layer and lead-free solder alloy was systematically investigated by scanning electronic microscopy(SEM)with EDX.The microstructure shows Ni3Sn4 layers growth at a lower rate in solder/Ni-P-ZrO2 joint compared with solder/Ni-P joint.The top-view intermetallic compounds(IMCs)layer in ZrO2 doped sample demonstrated a refined grain size.The consumption rate of amorphous UBM to crystalline Ni3P phase is limited in solder/Ni-P-ZrO2 joint due to the ZrO2 nanoparticle addition.Moreover,the ZrO2 nanoparticle doped sample consistently demonstrated higher shear strength than plain solder joint as a function of the number of reflow cycles.Therefore,Ni-P-ZrO2 UBM not only suppress the excess growths of IMC layer but also helps to reinforce the mechanical property of solder joint,thus improve the reliability of the interconnect.
Electroless plating solder joint lead-free microstructure intermetalic compound
Xiao HU Y.C.CHAN
EPA Center,Department of Electronic Engineering City University of Hong Kong 83 Tat Chee Avenue,Kowloon,Hong Kong,China
国际会议
The 15th International Conference on Electronic Packaging Technology (ICEPT 2014) ) (第十五届电子封装技术国际会议)
成都
英文
820-824
2014-08-12（万方平台首次上网日期，不代表论文的发表时间）