Laser surface cleaning of electronic materials

Abstract

Laser cleaning was demonstrated both theoretically and experimentally to be an effective cleaning technique for removing particulate and thin film contaminants from electronic materials. Two types of laser cleaning techniques have been discussed, relying on pulsed laser of the surface without or with the presence of a thin liquid coating. For dry and steam laser cleaning, cleaning models were established for removal of particles from substrate surfaces without or with a thin liquid layer by taking adhesion forces and cleaning force into account. The models not only explain the influence of laser fluence on cleaning efficiency, but also predict the cleaning thresholds. The laser-induced removal of organic thin film contaminants is considered due to laser ablation of the contaminants. Applications of laser cleaning to clean magnetic sliders, magnetic media surfaces, IC mold and PCB (Printed Circuit Board) will also be addressed.