Development of an opto-hydrodynamic process to remove nanoparticles from solid surfaces

Abstract

We developed a surface cleaning process to remove nanoscale contaminants as small as 10nm from solid surfaces using a laser-induced micro liquid jet. In the process, laser-induced breakdown of a micron-sized water droplet (∼10nl) produces a high-speed jet with speeds up to 1600m/s liquid jet via an explosive vaporization process. Impingement of the liquid jet with atomized droplets on the contaminated substrate removes the nanoparticles under the hydrodynamic drag forces. The process parameters, including the incident laser energy and the position of the droplet relative to the laser focus, were optimized to maximize the cleaning power. Polystyrene latex particles 20, 30, or 90nm in diameter and Al2O3 particles 10–50nm in diameter were used to demonstrate the cleaning performance of the opto-hydrodynamic cleaning technique. The proposed cleaning process is expected to be useful for selectively cleaning local areas with minimal exposure to water.