Effect of microbubbles on ozonized water for photoresist removal

Abstract

The existence of microbubbles in ozonized water has been shown to significantly enhance the photoresist removal rate due to an elevated dissolved ozone concentration and a direct effect of the microbubbles relating to the radical generation. Additionally, the ozone microbubble solution was able to effectively remove a high-dose ion-implanted photoresist, which is extremely resistant to removal by ozonized water and other wet chemicals because of its amorphous carbon-like layer, or “crust”. Electron spin resonance experiments were also performed without the influence of serious metal contamination and indicated the presence of hydroxyl radicals, which are thought to be formed by interaction of ozone with hydroxide ions adsorbed at the gas-water interface upon collapse of the microbubbles.