Laser surface cleaning of aluminum alloy

Laser ablation technologies by giant pulse lasers are getting wider use in drilling of printed circuit board and physical vapor deposition of various materials, in which precision drilling or stoichiometric vaporization are possible with less thermal effect. The authors have paid a special attention to apply laser ablation technology to surface cleaning of the specially extruded aluminum alloy used for ultra-high vacuum chamber. A KrF Eximer laser and a Q-switched YAG laser were irradiated on the aluminum alloy surface. Cleaned surface were observed by an optical microscope and analyzed by an Auger electron-spectroscope. The laser shot surface showed a slight evaporation trace with no carbon contamination. The energy balance of beam absorption in the non-contaminated aluminum-oxide layer and aluminum surface was estimated by calculation, and it is concluded that the surface cleaning was not achieved without oxide contamination.