Study On The Reliability Of Military Electronic Modules’ Lead-free Solder Joint

With the implementation of lead-free directive, lead-free manufacturing time hascome. The reliability of solder joints in electronic products directly related to the lifeof the product, but the reliability of lead-free solder joints is watching or disputes，Where the military electronic products are used in the special nature and environment,lead-free materials and the lead-free manufacturing process is still the research stage.Using reliability of experimental and finite element analysis to study the mechanicalproperties and fatigue life of lead-free solder joints, has important significance on thelead-free implementation of the military electronic products.Through reliability enhancement experiments, Lead-free BGA solder joints didnot show failure under the military electronics module requires rigorous thermalcycling and random vibration loading conditions. It can provide the SMT process andthe reliability of evidence for military electronic products using lead-free process.With ANSYS software, based on the actual production of the electronic modulewith BGA devices，a diagonal cutting the solder joint shape prediction model wasestablished. It simulated the mechanical behavior and fatigue life und the loadingprocess in the thermal cycling and random vibration loads. It laid the foundation foroptimal design of military electronic modules in composite environmental factors.Solder alloy of lead and lead-free solder joint reliability analysis are analyzedand compared, the conclusion have some reference for lead-free solder alloys appliedin military electronic product design and mount, and the actual production of SMT.The reliability of the BGA lead-free solder joint with different pad size and differentstencil openings was compared und thermal cycling and random vibration loading. Itconcluded that appropriate pad and stencil openings increases size, can improve thefatigue life of solder joints In the case of welding quality assurance. It has certainsignificance for more variety, small quantities of military product development, SMTprocess optimization aspects of design and other fields.