Semiconductor: Dissolved Ozone Equipment Controls Periodic UPW Ozonation

In the southwest US, one of the world's top 10 semiconductor companies designing and manufacturing embedded semiconductors for automotive, consumer, and other industrial markets, faces the daily challenges of efficiently maintaining a large UPW (Ultrapure Water) system. The factory is an 8-inch (200 mm) wafer manufacturing facility. A 160,000-squarefoot facility produces microcontrollers and embedded flash memories for their various markets. Manufacturing capability at the factory currently reaches the 0.18- micron technology node and started production back in the early 1990's. The facility uses periodic ozonation to ensure their UPW distribution loop is free from bacteria. The THORNTON ozone sensor measures the ozone output level and allows the UPW Plant Operator to adjust, or tune, the ozone generating system output to ensure ozone concentration achieves an effective oxidation level. Although there are many steps in the water purification process, bacterial and microorganism contaminants often exist in distribution loops. Loops such as the one in this facility transport large volumes of ultrapure water in plastic pipe comprised of many connection fittings, sample points and sensor installation locations. All of these can contribute to increasing contamination levels if not routinely cleaned.