Oxidation Behavior Of Copper Based Bonding Wires And Its Effect On Ultrasonic Bonding Performance

Copper-based bonding wires,an important basic material in the microelectronic packaging industry,fail to be packaged after being oxidized by the environment,and the reliability will also decrease.This paper mainly studies the performance fluctuation of YC2(20 μm pure copper bonding wire),YC3(20 μm alloy copper bonding wire)and YCP(20 μm palladiumplated copper bonding wire)bonding wires from Yantai Yinuo Electronic Materials Co.,Ltd.in the application process.Through the experimental method of ambient temperature variables,the correlation between the oxidation behavior and bonding performance of micron-sized copper-based bonding wires was studied.In this study,the influence of oxidation temperature,material properties,burn-ball process and other factors on the performance is explored,and the influence of oxidation state on the spherical ability and bonding ability of the bonding filament is determined by experiments.This paper studies the feasibility of process optimization for improving the performance of bonding wires,and gives reasonable process suggestions to help enterprises improve in quality control management and product use.The full-text study and findings are as follows:(1)The resistance growth rate can be used to evaluate the bonding ability of YC2,YC3,and YCP whose conductivity deteriorates due to environmental oxidation.The three copperbased bondwire resistors increase at a rate of 0.618 mΩ/min?m,1.092 mΩ/min?m,and 1.5428mΩ/min?m.When the resistance increases per meter of YC2,YC3 and YCP reach 3.51%,2.40%and 0.80%,respectively,the bonding wire loses its value.The ambient temperature has a significant effect on the resistance growth rate.(2)The reason for the different mechanical properties of 20 microns after oxidation of YC2,YC3 and YCP is that the composition is different.During the experimental period,the decreasing rates of YC2,YC3,and YCP breaking force under 100 ℃ environment oxidation were 0.0126 gf/min?m,0.0168 gf/min?m,and 0.1630 gf/day?m,respectively;The decreasing rates of YC2,YC3,and YCP breaking force under 150℃ environment oxidation are 0.0123gf/min?m,0.0445 gf/min?m,and 0.0103 gf/min?m,respectively;The decreasing rates of YC2,YC3,and YCP breaking force under 200℃ environment oxidation are 0.0449 gf/min?m,0.1570gf/min?m,and 0.0172 gf/min?m.The results show that the bonding wire without coating protection is more susceptible to the influence of temperature environment and reduces the tensile strength,and the tensile performance of the bonding wire with coating protection decreases slowly.(3)Ambient temperature oxidation reduces the spheroidizing and bonding ability of bonding wires that are not protected by coating.The plating improves the bonding ability of YCP.The oxide film causes spherical eccentricity,reduced bond strength,and interfacial bonding performance;Oxidation causes the FAB hardness of YCP to increase and overbonding.(4)Optimizing the bonding process can improve the bonding ability and interfacial bonding performance of the bonding wire after long-term oxidation.By optimizing the parameters such as ultrasonic current,pressure welding current,pressure welding pressure,bonding temperature,and shielding gas flow,the eccentricity of spherical FAB caused by surface oxidation of the wire can be improved,and the bonding damage caused by surface oxidation can be reduced.After understanding the intrinsic relationship between bonding parameters,oxidation state,and bonding ability,the maximum value of the oxidized bonding wire is exerted by increasing the bonding parameters of the adjustable parameter interval.