Thermomechanical behaviour of PBGA package during laser and hot air reflow soldering

摘要

In this paper, the temperature distribution in laser reflowed solder balls and warpage of the package upon temperature change were simulated using a finite element method, and effects of different laser heating means on the temperature distribution have been discussed in detail. The results of simulation show that solder balls reflowed by laser heating power would not damage the silicon chip and the package and that with laser, the advantages of a short heating time, a lower temperature in the package and smaller deformation were obtained as compared with a traditional heating method such as the hot air reflow method. Also, experiments on a plastic ball-grid-array (PBGA) solder ball laser reflow were carried out. Results show that the surface of the solder bumps obtained by the laser reflow method with proper parameters is much smoother than that obtained by the hot air reflow method.