Effects Of Ultrasonic Vibration And Electrical Field On Wettability And Soldering Of Sn2.5Ag0.7Cu0.1RE/Cu

Fast development of electronic packaging and assembly with lead-free solder,butits serious wettability affect the quality and reliability of lead-free solderjoints.Seeking effective improve the wettability of lead-free solder and solderingtechnology，new technique measures were the key problems urgently to be solved inproduction.This study took Sn2.5Ag0.7Cu0.1RE/Cu as the research object,based onthe experiment facts that ultrasonic vibration and electric fields helps remove oxidefilm,improve the wettability and control interface solute mass transfer,an solderwetting and soldering test device was developed that under the action of ultrasonicvibration and electric field,and developed the solder wetting and soldering newtechnology that under the action of ultrasonic vibration and electric field,opens a newway to improve the wettability and soldering process of solder including SnAgCuREseries lead-free solder.The solder wetting and soldering test device developed by the combination ofultrasonic vibration and electric field was consists of five parts:ultrasonic generationsystem that provide a stable ultrasonic vibration load;ultrasonic vibration transferdevice that make sample or specimen is under the action of ultrasonic vibration andelectric field;high voltage power supply system that offers a variety of types of voltagestability;electric field applied device that make samples or specimens in a uniform andstable electric field;the heating and temperature control system that ensure sample orspecimen at a given temperature.Research has solved the insulation problem that underheating,high frequency vibration and under the environment of high voltage,make thedevelopment of the device has the technical characteristics that overall test of highprecision,easy to use and safe and reliable operation,it can fully meet the solderwetting and soldering test,applied research needs that under the action of ultrasonicvibration and electric field.To systematically study the effect of ultrasonic power,electric field intensity,ultrasonic time and electric time on Sn2.5Ag0.7Cu0.1RE/Cu wettabilityunder the action of ultrasonic vibration and electric field by orthogonal and singlefactor experiment.Wetting mechanism are discussed,confirm the optimum wettingprocess parameters,on the basis Sn2.5Ag0.7Cu0.1RE/Cu soldering experiments underthe action of ultrasonic vibration and electric field were carried out.The results show that the action of ultrasonic vibration and the electric field canimprove Sn2.5Ag0.7Cu0.1RE/Cu wettability,and the effect of ultrasonic vibration ismore significant;The best wetting optimum technological parameters ofSn2.5Ag0.7Cu0.1RE/Cu that under the action of ultrasonic vibration and electric fieldwas ultrasonic power88w,electric field intensity1.5kV/cm ultrasonic time45s andelectric field time60s,which under the condition of temperature270℃,wetting120sget Sn2.5Ag0.7Cu0.1RE/Cu minimum wetting angle is28.19°,compared to noultrasonic vibration and electric fields of wetting angle reduced23.31°,achieve thestandard of industrial wettability evaluation "very good";in wetting conditions abovethe Sn2.5Ag0.7Cu0.1RE/Cu soldering240s,the soldering joint shear strength was27.8MPa,compared to no ultrasonic vibration and electric fields of soldering jointshear strength increased by49.95%;ultrasonic vibration can effectively break parentmetal surface oxidation film,the electric field can reduce the wetting of solid liquidinterfacial tension,promote the uniform interface mass transfer,thereby improvingSn2.5Ag0.7Cu0.1RE/Cu wettability,and further more improve the soldering jointmechanical properties.