Laser Ablation General Information Laser ablation uses short pulses of high peak power laser radiation to rapidly heat and vaporize thin layers of contaminants. Laser ablation is being used, at one extreme, to remove paint from very large aircraft surfaces and, at the other extreme, to remove thin films and particles from semiconductor wafer surfaces. The laser ablation process used on semiconductor wafers uses an adsorbing transfer medium, a liquid, to remove particles. As the transfer medium is vaporized by the laser, it carries off particle contaminants. Energy transfer media include: water, methanol, ethanol, and 2-propanol. IBM has found that a 9:1 water:alcohol solution works well. The water provides higher transient pressures due to superheating, while the alcohol helps wet the surface to be cleaned. More efficient cleaning has been observed when the laser wavelength is chosen for optimal absorption by the substrate rather than by the liquid or contaminant. Laser ablation will work on partially or completely assembled parts. Laser ablation can remove very thin layers, such as chromium oxide from 304L stainless steel. State Information | Glossary | Conversion Checklist | Comments Home | Process Advisor | Alternatives | Links | Search All SAGE material, Copyright© 1992, Research Triangle Institute Last Update: 15 March 1995 sage@rti.org http://clean.rti.org/alt.cfm?id=la&cat=gi