| At present, the development of electronic packaging technology is very rapid, small, light and thin is the main direction of development of the technology, the reliability of solder joints itself has been a hot issue in the field of scientific research. Lead solder harm to human body and the environment, and in the green environmental protection requirements, so electronic package to be shipped in lead-free solders gradually replaced the lead solder. The size of the solder joint has a close relationship with the performance of the solder joint. In this paper, the thermal reliability of solder joints is studied by analyzing the different diameter, height and different solder composition of lead free solder joints.BGA technology has gradually become the main form of high-end IC packaging, but now its lead-free solder joint fatigue fracture of the research is not enough, so the lead-free solder ball grid array on the reliability level of great scientific value. For this paper, lead-free solder joints by finite element thermal simulation knowledge, and then to analyze its reliability and reasonable circumstances. Sn3.0Ag0.5Cu solder itself has good characteristics, the paper selected ball Sn3.0Ag0.5Cu under thermal cycle heat load, heat transfer using common tools ANSYS Workbench for solving heat PBGA components. First consider the impact pad diameter, holding joint height constant boundary conditions and heat load are constant, changing the diameter of the solder joint is solved in danger of lead-free solder joint strain comparison and analysis, the risk of solder joints of different diameters forecast the thermal fatigue life. In considering the impact of the height of solder, solder joint keeping a constant diameter, boundary conditions and heat load are the same, change the height of the solder joint is solved using the Coffin-Manson equation,analysis and forecasting of different high-risk joints under thermal cycling conditions fatigue life,to arrive at a higher reliability of solder joints. Finally, under thermal cycling conditions and comparative analysis of lead-free solder has Sn3.0Ag0.5Cu temperature lead solder Sn63/Pb37 distribution of stress and strain and thermal fatigue life.Therefore, in the application of electronic packaging engineering, the diameter and height of PBGA lead-free solder joints should be controlled within a reasonable range, and then to ensureits reliability. Lead free solder Sn63/Pb37 and lead solder Sn3.0Ag0.5Cu solder joints due to different composition and thermal reliability is also different. Through the research of this paper,it is helpful to understand the failure mechanism of lead free solder joints under thermal cycling condition, and it has a certain reference value for the practical application of BGA lead-free solder joints in practical applications. |
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