Research on Mixed Assembly Soldering Technology of Leaded BGA with Low Temperature Resistance and Lead-Free BGA

In view of the situation that the mixed soldering process window of low temperature resistance lead BGA devices and lead-free BGA devices is too small and it is impossible to realize non-destructive soldering of low temperature resistance BGA devices by using the temperature curve of conventional lead paste compatible lead-free BGA devices, two solutions are proposed in this paper: Firstly, the model of reflow furnace and PCBA was established and the reflow soldering process was simulated by finite element simulation method. Through the iterative optimization of simulation process and sorting and screening of simulation results, the process curve meeting the soldering requirements of the upper temperature of components with low temperature resistance value and lead-free BGA was determined. Secondly, the thermal barrier method of low temperature resistance components is adopted, and appropriate heat insulation fixture is designed to make the low temperature resistance BGA devices obtain appropriate temperature curves under the conventional mixed installation process window. The experimental results show that the two methods can obtain the suitable temperature curve of low temperature resistance soldering with lead BGA and lead-free BGA, and the second method has better applicability in the case of many kinds of products and small batch.