[News Terms] Ultrapure Water, the Lifeblood of Semiconductors Nearing Domestic Production

Ultra Pure Water (UPW) is pure water that has had all minerals, particles, bacteria, microorganisms, dissolved gases, and other impurities removed, leaving only the hydrogen and oxygen that make up water. It is also called DIW (De-ionized Water) because its ionic components have been removed.

Ultrapure Water Production Process

Produced through more than 20 stages of processes such as ion exchange, reverse osmosis, membrane filtration, and distillation, UPW is characterized by extremely low levels of ionic impurities, solids, bacterial counts, organic matter, and dissolved substances. It also has higher electrical resistance than other pure waters, allowing almost no electric current to flow. Because of this, electronic devices can be operated inside UPW just as they would be in air. This property makes UPW essential in specialized industries such as semiconductor manufacturing, nuclear power generation, and biotechnology.

UPW plays a particularly significant role in the highly competitive semiconductor industry. A semiconductor chip undergoes numerous processes known as the eight major steps before completion. UPW is mainly used for cleaning before and after these various processes. For example, it is used to wash away debris left after the etching process or to remove residual ions after the ion implantation process. UPW is also used during wafer polishing and wafer cutting. If semiconductors, which involve ultra-fine processes at the nanometer scale, are not washed with UPW, particles can form and cause defects. In other words, UPW cleaning is essential to increase the yield, or productivity, of semiconductor manufacturing. Typically, more than 1 ton of UPW is used to process a single 6-inch wafer. According to the global water industry research organization Global Water Intelligence (GWI), the global utilization rate of UPW by semiconductor companies was about 40% as of 2021.

Although UPW is an indispensable material in semiconductor processes, known as the lifeblood of semiconductors, South Korea, a semiconductor powerhouse, has not had the technology to produce UPW until now. Since producing wafers for the first time in 1983, South Korea has been supplied with UPW from facilities designed by Japanese companies. However, this changed in 2021 when the Ministry of Environment launched the ‘Development Project for Domestic Technology of High-Purity Industrial Water (UPW),’ accelerating localization efforts. Recently, Hanseong Cleantec, a water treatment specialist company, succeeded in localizing UPW-related equipment. Industry insiders say that equipment localization is necessary to recognize UPW as truly ‘domestically produced.’