Non-contact removal of 60-nm latex particles from silicon wafers with laser-induced plasma

In micro- and nano-manufacturing particles are created and circulated as by-products of the processes utilized. The removal of micro- and nano-particles during manufacturing processes is of great importance in many industries, including semiconductors, optics, photonics and microelectromechanical systems (MEMS). One specific application is in the cleaning of silicon wafers. According to the 2002 update of the International Technology Roadmap for Semiconductors, by the year 2006, techniques for the removal of polystyrene latex (PSL)-equivalent particles with size less than 35 nm will be required and currently, according to the roadmap update, there is no known method to remove PSL-equivalent particles smaller than diameter D = 40 nm. The current study reports and demonstrates a non-contact laser-induced plasma method for removal of particles with D = 60 nm. Non-contact techniques are desired to reduce the risk of substrate damage. Chemical usage in traditional cleaning methods is also a serious concern for process cost, workplace safety and environmental conservation. The development of dry, rapid, non-contact and non-damaging nanoparticle removal methods is, therefore, a critical need for various applications. Using a scanning mechanism, the process discussed can be automated for rapid cleaning of large silicon wafers.