A study on the degassing mechanism of Pb-based alloy under ultrasonic treatment

Abstract

In recent years, the ultrasonic technique is being developed at a pretty faster speed, whose assisting tactic has been applied in the electronic packaging field. What we need is to determine the mechanisms of ultrasonic treatments on electronic packaging fillers. In this paper, Pb-based alloy is typically chosen as the filler metal, in this paper, it is found that the flowability of which can be improved under ultrasonic vibration. Also, ultrasonic degassing efficiency is greatly promoted, with the best parameter for degassing that ultrasonic power and duration time of 1000W and 60s, a molten alloy’s treating temperature of 340°C. The assistance of ultrasonic is deeply explained from the thermodynamic aspect. Understanding of the atomic level interactions of liquid Pb atoms and vacuum is crucial, so we make an ultrasonic-assisted molecular dynamic simulation of melting Pb to room temperature to 330°C in 10ps, and the diffusion behavior of Pb atom under periodic vibration is revealed.