Ag-Sn低温过渡液相连接中Ag_3Sn晶粒的生长机理（英文）

Mechanism of Ag_3Sn grain growth in Ag/Sn transient liquid phase soldering

低温过渡液相(TLP)连接是一种在宽禁带半导体互连领域极具应用潜力的高温电子封装技术。本文研究了Ag/Sn体系在不同温度下进行TLP连接时界面金属间化合物(IMCs)的生长机理。结果表明:Ag_3Sn晶粒主要呈扇贝状形态,而棱柱状、针状、中空柱状、板状和线状等形态也会产生;然而,随着保温时间的延长波浪状Sn/Ag_3Sn界面将变得更加平坦,分析表明这与晶粒粗化及基板Ag原子各向异性的扩散流有关;同时,在Ag_3Sn晶粒表面观察到大量纳米Ag_3Sn颗粒形成,它们形核长大于液相富Ag区,并在凝固过程中被Ag_3Sn晶粒吸附沉淀所致。在动力学方面,Ag_3Sn晶粒生长遵循抛物线规律,主要受到体积扩散控制,且250、280和320°C下生长速率常数分别为5.83×10^(-15)、7.83×10^(-15)和2.83×10^(-14)m^2/s,反应活化能为58.89 kJ/mol。

Transient liquid phase(TLP)bonding is a potential high-temperature(HT)electron packaging technology that is used inthe interconnection of wide band-gap semiconductors.This study focused on the mechanism of intermetallic compounds(IMCs)evolution in Ag/Sn TLP soldering at different temperatures.Experimental results indicated that morphologies of Ag3Sn grains mainlywere scallop-type,and some other shapes such as prism,needle,hollow column,sheet and wire of Ag3Sn grains were also observed,which was resulted from their anisotropic growths.However,the scallop-type Ag3Sn layer turned into more planar with prolongingsoldering time,due to grain coarsening and anisotropic mass flow of Ag atoms from substrate.Furthermore,a great amount ofnano-Ag3Sn particles were found on the surfaces of Ag3Sn grains,which were formed in Ag-rich areas of the molten Sn and adsorbedby the Ag3Sn grains during solidification process.Growth kinetics of the Ag3Sn IMCs in TLP soldering followed a parabolicrelationship with soldering time,and the growth rate constants of250,280and320°C were calculated as5.83×10-15m2/s,7.83×10-15m2/s and2.83×10-14m2/s,respectively.Accordingly,the activation energy of the reaction was estimated about58.89kJ/mol.