(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 通过加速温度时效方法针对电子器件可靠性评估中等温时效对In-3Ag焊料显微观组织和剪切性能的影响进行研究。采用扫描电镜(SEM)、能量色散仪(EDS)和X射线衍射(XRD)分别对焊点基体及其与铜基板界面金属间化合物层的组织结构进行观察和分析，采用力学试验机测试焊点的剪切强度，并通过SEM观察分析其断裂特征。结果表明：随着等温时效时间延长，基体中二次相AgIn2显著长大，由颗粒状转变为大块状；界面IMC层(成分为(Ag,Cu)In2)的厚度逐渐增加，其生长由组元扩散速率控制；焊点剪切强度呈下降趋势，由焊后的5.94 MPa降至时效1000 h后的2.35 MPa；在100 ℃分别时效100、250、500和750 h后，焊点剪切失效均呈焊料内部韧性断裂模式，时效1000 h后，断裂模式转变为韧脆混合断裂。
关键字: In-3Ag焊料；金属间化合物；等温时效；剪切性能；钎焊
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The effects of isothermal aging on the microstructure and shear property of In-3Ag solder were investigated by accelerated temperature aging. Scanning electricity microscope (SEM), energy dispersive spectrometer (EDS) and X-ray diffractometer (XRD) were used to observe and analyze the intermetallic compound (IMC) layer microstructure and the composition of solder joint. The mechanical testing machine was used to test the shear strength of solder joint, and the shear fractography was measured by SEM. The results show that, with the isothermal aging time increases, the quadratic phase AgIn2 in solder matrix grows prominently, and the shape changes from grain to blocky ship. The thickness of (Ag,Cu)In2 layer increases gradually, which is controlled by component diffusion rate. The shear strength of solder joints decreases with isothermal aging time increases, and it decreases from 5.94 MPa after soldering to 2.35 MPa after 1000 h aging. The fracture type is ductile fracture in solder matrix after being aged at 100 ℃ for 100, 250, 500 and 750 h, respectively. After being aged for 1000 h, the fracture type belongs to the toughness-brittleness fracture mode.
Key words: In-3Ag solder; intermetallic compound; isothermal aging; shear property; soldering
