Acoustic power dependent detachment of PSL particles adhered to glass surfaces by dissolved gas and anionic surfactant in an ultrasonic field

Abstract

While numerous cleaning techniques have been proposed for the semiconductor cleaning process, the ultrasonic cleaning method has become an increasingly adopted technique that removes contaminated particles from semiconductor devices. Till date, little attention has been given to understand the role of surfactant and dissolved gas on the dynamics of cavitation bubbles at different ultrasonic powers. In this study, we propose a mechanism for the influence of SDS (sodium dodecyl sulfate) and dissolved H2 gas in deionized water (DIW) on the removal of PSL particles at different ultrasonic powers by evaluating the particle removal efficiency (PRE) via high-speed videography. It was observed that at US (ultrasonic) powers of 12 and 16 W, the PRE reached a maximum value at a SDS surfactant concentration of 20 ppm and then drastically decreased with increasing surfactant concen-tration. However, H2 gas dissolved DIW shows a high PRE compared to DIW at US powers of 4-16 W. Furthermore, the PRE reached a maximum value at 20 ppm SDS in a H2-DIW solution and then decreased with increasing surfactant concentration up to 100 ppm. However, the PRE decreased slightly with increasing SDS surfactant concentration when dissolved in H2-DIW. It was revealed that the US power and concentration of SDS significantly influence the removal of PSL particles. Furthermore, the size, cluster, population, and dynamic characteristics of bubbles affected the PRE differently in the presence of SDS and H2 gas. Our present research demonstrates a different approach towards the development of a more feasible ultrasonic cleaning process.