Laser surface cleaning of organic contaminants

Laser surface cleaning process has been a useful and efficient technique for various industrial applications. The removal of photoresist contaminants on silicon wafers was investigated with a krypton fluoride KrF.excimer laser, and the irradiated area was characterized using a profilometer, a scanning electronic microscopy SEM., an Auger electron spectroscopy AES. and a Fourier transition infrared spectroscopy FT-IR.. It was found that there exist an optimal number of pulses to remove the contaminant from the substrate surface without any laser-induced damage, depending on the laser density on the surface. A model to predict the optimal number of pulses, which agrees well with Beer–Lambert’s law, is proposed and proved to be operable. q1999 Elsevier Science B.V. All rights reserved