Advanced Ultrapure Water by  HF  Addition

Abstract

To improve ultrapure water, the additional effect of HF in pure water was investigated. Both formation of native oxide on the Si wafer surface and generation of viable cells in pure water can be prevented by using pure water containing HF on the order of parts per million instead of conventional pure water. Moreover, by using PFA or PTFE as a pipe material, pure water containing HF which was not contaminated by metal ions and viable cells can be fed to point of use without a circular line such as a conventional pure water feeding line.

Competitive Adsorption of Metal Ions onto Hydrophilic Silicon Surfaces from Aqueous Solution

“…Miyamoto and co-workers have described using low concentrations of HF in the water. 2 Shiramizu and co-workers have described the use of electrolysis-ionized water containing NH 4 Cl to keep the pH low and remove and keep off metallic impurities. 3 Lampert and Fabry have suggested the addition of CO 2 to water.…”