Study On The Effect Of Wave Soldering On BGA Solder Joints In A Mixed Process

For the BGA chip and the DIP mixed circuit board contact, in addition to the reflow welding process, the need for wave soldering process. BGA solder joint, in the process of wave soldering process in large temperature gradient, BGA solder joint under thermal shock, easy to cause the cracking of a solder joint; and the molten solder directly with printed circuit board contact in molten solder at the temperature above 230 degrees in general, but also easily lead to BGA welding melting point two times.In order to study the influence of wave soldering on BGA solder joint, the feasibility of plan is established. The temperature curve of the appropriate debugging according to reflow profile debugging principle, the reflow temperature curve of BGA chip and the BGA solder joint welding,observation BGA chip center, edge and corner joints, there were no voids and cracks,ensure the reflow after BGA the solder joint is reliable. To verify the influence of wave soldering of BGA solder joints, re manufacture test board, and according to the principle of wave soldering temperature curve debugging a proper soldering temperature curve.In the process of wave soldering process test board, the establishment of the physical model, transient thermal analysis was performed to validate the analysis results using the temperature tester, the simulation is reliable, and the highest temperature in the solder tin lead alloy liquidus, therefore BGA solder joint in wave soldering will not appear two times of melting phenomenon. Using the sequential coupling method, the transient thermal analysis as a result of the static load input force analysis, the process of wave soldering for static stress analysis of test plate experience, stress along the BGA chip by the BGA chip diagonal, the center outward gradually increased, the maximum stress in the angle of BGA solder joints.Referring to the BGA solder joint stress distribution of the wave soldering test board for metallographic analysis and conventional process inspection, observing the BGA center, edge and corner solder joint characteristics, solder joint in accordance with the relevant standards. Study on the analysis of simulation and metallographic combination, wave soldering on the soldering temperature curve, the maximum stress distribution in the solder angle of BGA solder joints, and no solder joint cracking phenomenon; the highest temperature in the BGA solder tin lead alloy liquidus, also won't happen two times of melting phenomenon.