一种新型SnZn系中温高强无铅焊膏制备及性能分析

Preparation and performance analysis of a new type of SnZn medium-temperature high-strength lead-free solder paste

制备了一种新型SnZn系无铅中温高强焊膏,合金成分为Sn-9Zn-2.5Bi-1.5In,熔点为195℃,具有良好的印刷性能和焊接性能。研究了SnZn焊膏的抗剪强度,并与市场上领先的SnAgCu系焊膏、SnBi系焊膏做对比。结果表明,SnZn系焊膏的抗剪强度在表面喷锡焊盘上优于其他两种焊膏(较SnBi系高14%,较SnAgCu系高25%),在化镍金焊盘上劣于其他两种焊膏,在OSP焊盘上介于两者之间。同时,研究发现SnZn系焊膏在温度曲线最高温度为215℃时获得最佳抗剪强度62.9MPa,通过观察SnZn系焊膏焊点的剖面,分析其元素分布,确定了焊点在元件及焊盘表面形成的金属间化合物(IMC)。

A new type of SnZn-based lead-free medium-temperature high-strength solder paste was prepared. The alloy composition was Sn-9Zn-2.5Bi-1.5In with a melting point of 195 ℃, which has good printing performance and welding performance. The shear strength of SnZn solder paste was studied and compared with the leading SnAgCu solder paste on the market and SnBi solder paste. The results show that the shear strength of SnZn solder paste ishigher than that of the other two solder pastes on the surface tin-plated solder pads (14% higher than SnBi system and 25% higher than SnAgCu system), which is inferior to other nickel-gold pads. Two solder pastes are placed between the two on the OSP pad. At the same time, it was found that SnZn solder paste obtained the highest shear strength of 62.9 MPa when the maximum temperature of the temperature curve was 215 ℃. By observing the profile of SnZn solder paste solder joints, the element distribution was analyzed and the soldered joints were determined. An intermetallic compound (IMC) formed on the surface of the disk.