Study on microstructure and reliability of SnAgCu and SnPb solder joints

With the development of lead-free soldering processes in electronic assembly, more and more lead components have being replaced by lead-free components. In the field of high-reliability electronic products such as military industry, SnPb solder paste is still widely used, so the soldering of lead-free components with SnPb paste in electronics manufacturing is inevitably. This paper analyzes the solder joints with SAC305/Sn63Pb37/HASL in mixed soldering, discusses the formation mechanism of Intermetallic Compound and the reliability of solder joints. The experimental results show that the solder joints have good reliability when the peak temperature is 225°C~235°C and the soldering time above 183°C is more than 80s.