Abstract

As microelectronic fabrication technology advances, there has been an ever-increasing need to develop more effective techniques to remove submicron-sized contaminants.¹ A submicron particle adheres strongly onto a surface, with a force as large as millions of times its weight. Recently, it has been demonstrated that explosive vaporization and ablation of a thin liquid film on a solid surface induced by short-pulsed laser irradiation can be efficiently used to remove submicron-sized particulates from the surface.² It has been also demonstrated that lasers can provide an environmentally sound, cost-effective method of removing organic coatings from a variety of substrates.³ Two kinds of laser-assisted cleaning technique have been developed, i.e., "steam laser cleaning" and "dry laser cleaning."² The first kind utilizes flash heating and subsequent rapid vaporization of a micron-thick liquid film which is deliberately deposited on the surface. It has been shown that a strong acoustic wave is generated by the explosion which is responsible for the removal of particles.⁴ The second utilizes ablative photodecomposition of organic substances which are adsorbed on the surface. Hence, cleaning can best be done with the combination of these two laser cleaning modes.

© 1994 IEEE