低银无铅焊膏板级封装工艺和焊点可靠性试验

针对低Ag无铅焊膏的市场需求,研究开发了一种适用于99.0Sn0.3Ag0.7Cu低Ag无铅焊膏用松香型无卤素助焊剂(WTO—LF3000),配制了相应的无铅焊膏(WTO—LF3000—SAC0307),并对其板级封装工艺适应性及焊点可靠性进行了考察,用测试后样品的电气可靠性作为接头可靠性评价条件。结果表明:所开发的低Ag无铅焊膏熔点和润湿性符合产品实际要求。配制的焊膏印刷质量良好,焊点切片观察其孔隙率<25%,满足行业标准IPC—A—610D之要求。样品分别经跌落、震动和温度循环试验后,无焊点脱落等现象,电气功能正常。

Board-level packaging process and solder joint reliability test of a low-Ag lead-free solder paste

For the market demand of the low-Ag lead-free solder paste, a rosin-based halogen-free flux (WTO-LF3000) which is suitable for 99.0Sn0.3Ag0.7Cu the low-Ag lead-free solder paste (WTO-LF3000-SAC0307) was developed. Its board-level packaing printing and reflow process adaptability, as well as the solder joints reliability were tested. The electrical reliability of the tested samples was used as the solder joint's evaluating condition. Results show that the melting point and wettability of the solder paste meet the actual requirements of products. The solder paste has a good printing quality. There is no collapse and bridge phenomenons for the joints. The solder joint porosity (<25%) meet requirements of the inclustry standard IPC-A-610D. Through the drop, vibration and the temperature cycling tests, the solder joints have no peeling off, and the electrical functions of the tested samples are favorable.