Study On Fatigue And Electrical Properties Of COG Assembly Under The Multi-field Coupling Effects

With the development of science and technology,the demand for electronic packaging technology is increasing.COG packaging technology has been gradually replaced the traditional packaging technology owing to its advantages,such as environmentally benign,fine pitch capability,simple structure and manufacturing process with low processing temperatures,light weight and small product size.However,the study of fatigue and electrical properties COG assembly under the multifield coupling effects is relatively few.In this paper,the mechanical properties and relative resistance of the COG assembly under the constant temperature-electromechanical coupling effects or the salt spray-electro-mechanical coupling effects.This is important for the development of COG packaging technology.The fatigue life and resistance change of COG assembly have been studied under the constant temperature with the use of micro fatigue testing machine and oven.The result shows that the fatigue life of the COG assembly decreases with the increase of load amplitude at a certain temperature;simultaneously,the fatigue life of the COG assembly decreases with the increase of environmental temperature at a certain loading amplitude;meanwhile,the resistance change of COG assembly is related to both of the loading amplitude and environmental temperature.The effects of salt-spray corrosion on resistance of COG assembly and the coupling influence of environment-electric-mechanical on the bonding properties of COG assembly have been studied with the help of salt-spray corrosion test.Firstly,the relative resistance of COG assembly increases with the increase of corrosion time;then,the effect of salt-spray corrosion time on the shear strength and the maximum shear displacement have been studied.It is found that the shear strength and maximum shear displacement decrease with the increase of salt-spray corrosion time.The fatigue life and resistance change of COG assembly have been researched after salt-spray corrosion.The results show that the fatigue life of COG assembly decreases with the increase of salt-spray corrosion time under the certain loading condition;meanwhile,the relative resistance of COG assembly increase rapidly in the initial phase,then the rise rate decreases,and finally the relative resistance increase quickly again with the increase of cycle number;finally,the Miner linear damage law has been used to define the damage of COG assembly,and the relationship between the salt spray corrosion time or relative resistance caused by salt-spray corrosion and the damage of COG assembly have been fitted.