Particle Adsorption Onto Si-Based Wafers in Ultrapure Water; Its Mechanism and Effect of Carbon Dioxide

Ultrapure water contains several kinds of contaminants. In particular, we paid much attention to particles and investigated particles adsorption onto Si-based wafers. We succeed in making a model through two experiments. One is to study an impact of spin cleaning parameters on particle adsorption, and the other is to study that of such impurities as urea, hydrogen peroxide, carbon dioxide, and so on. The former test succeeded in quantitatively estimating the magnitude of each degree of influence to some extent assuming that there are roughly two steps of attaching particles to the wafer, namely adsorption equilibrium during rinsing and residuals during drying. The latter is to confirm that substances that are likely to be mixed in ultrapure water do not affect particle adsorption in the future manufacturing process. We concluded that we need to pay attention to carbon dioxide especially in this system.