Research On Ultrasonic Energy Optimization And Bonding Quality Of Chip Wire Bonding

Wire bonding is an important part of chip packaging.With the development of electronic packaging industry,the requirements for chip volume and performance are getting higher.Ultrasound is an indispensable part of wire bonding process.The stability of ultrasonic energy output has great influence on bonding process.There are some problems such as single ultrasonic energy output mode,slow frequency tracking speed,and poor precision of ultrasonic generators used for wire bonding.In order to solve these problems,a better performance ultrasonic generator for the field of wire bonding has been designed,which has the advantages of high frequency tracking accuracy and editable energy output.Aiming at the problem of poor frequency tracking accuracy of ultrasonic generators for wire bonding,the feedback circuit is simulated.By analyzing the phase shift of the input and output signals of each stage of the feedback circuit,solving the transfer function of operational amplifier,changing the component parameters,the phase error caused by unreasonable design of hardware parameters is corrected.For the problem that the singlechip microcomputer has poor ability to capture high-frequency signals,a frequencydividing circuit is designed.The voltage and current signals are input to the single-chip microcomputer through the frequency-dividing circuit,so that the original circuit can only accurately detect the phase difference symbol to accurately collect the phase difference value.The corrected ultrasonic generator achieves a phase difference of zero under noload conditions.In view of the short bonding process and high stability requirements,PID is used as the controller of the ultrasonic transducer system.Considering the cumbersome characteristics of the traditional PID controller parameters,the particle swarm optimization(PSO)algorithm is introduced to control.The parameters of the device were optimized,and the ultrasonic transduction system was modeled in open-loop and closedloop,respectively.Considering that it is usually desirable to apply a small amount of ultrasonic energy at the beginning of the bonding,an editable energy loading mode is designed.The frequency tracking experiment of the ultrasonic generator under no-load condition is designed to verify the effectiveness of the frequency tracking algorithm under no-load conditions.The bonding experiment of the ultrasonic transducer system was performed,and the effects of different phase response performance and energy loading modes on the bonding quality of the solder joints were analyzed.