Ultrapure water markets and technologies
01/01/2007
Overall UPW market expected to grow through 2010
By Robert McIlvaine and Alpa Bagga, The McIlvaine Company
In the semiconductor industry, ultrapure water is used for cleaning and etching of wafers. Wafer rinsing, in particular, is responsible for the largest consumption of ultrapure water in the wafer fab. In the pharmaceutical industry, high-purity water is used as a product component as well as within production processes. Cleanroom laundries constitute a small share of the overall ultrapure water market, but within the cleanroom market, they are a major user of ultrapure water. Other industries that require ultrapure water include flat panel displays, biotech, and laboratory services.
Ultrapure water is potable, municipal water purified on-site to reduce the concentration of contaminants such as dissolved solids and ions, and especially the hardness components, calcium and magnesium.
A typical 200 mm wafer fab that processes approximately 40,000 wafers per month uses between 2 and 3 million gallons of water per day. About 70 percent of this water is used to produce ultrahigh-purity water (UHPW), which is part of the wafer-cleaning process. Much of this water is either recycled or reclaimed for use in other areas of the fab. Approximately 20 percent of the water is used for other, non-UHPW processes, such as cooling towers and heat exchangers. The remaining 10 percent is used for non-process-related parts of the fab, such as lawns, bathrooms and sprinkler systems.
 |
The pharmaceutical industry uses water for injection (WFI), which is water that has been further purified for use in medicinal products and for cleaning in place (CIP) processes in the pharmaceutical cleanroom. WFI water is typically produced using distillation or reverse osmosis.
Cleanroom laundries have developed various methods for clean processing of garments soiled with body oils, dirt, lint and chemical stains, while retaining only very low amounts of surface residuals. Many of these developments are proprietary, especially water (or solvent) polishing, wash chemistry and formulation. Other improvements have been made by upgrading the laundry environment to that of a modern cleanroom. Fully garmented workers, HEPA-filtered room and dryer air, low-shedding room and work surfaces, barrier washers, bag sealers, and protection of garments during handling and transport can have an impact on cleanroom garment quality. The basic requirement of the cleanroom laundry is that its clean facility be equal to or better than the cleanrooms in which the garments are used. This necessitates the use of high-purity water.
A typical ultrapure water system for the semiconductor industry includes reverse osmosis, ion-exchange, instruments and controls, degasification equipment, filtration equipment, pumps and valves, storage and piping, and disinfection. It is vital that every component of the ultrapure water system consistently maintain high purity.
Christ is a major supplier of ultrapure water systems. U.S. Filter provides central systems, pretreatment and point-of-use ultrapure water polishing systems. GE Water offers electrodeionization (EDI) systems, which remove not only residual salts but also ionizible aqueous species such as carbon dioxide, silica, ammonia and boron. Kurita supplies systems that utilize reverse osmosis, ultrafiltration and ion exchange technologies.
Reverse osmosis (RO) is the most widely used crossflow technique and produces the finest level of filtration of all the membrane processes. In RO, influent water is forced through a semipermeable membrane from a region of higher salt concentration to a more dilute region by applying a pressure that is greater than normal osmotic pressure. (Under normal osmotic pressure, water would move from the more dilute side to the more concentrated side.) RO is most often utilized to provide water that is almost free of solids, salts, organics and colloids to subsequent final polishing processes, such as ion exchange.
Reverse osmosis has made big inroads in serving as pretreatment for the ion-exchange system and, as such, greatly reduces the chemicals used for regenerating the ion-exchange resins and ultimately reduces resin consumption. The water produced by a combination ion-exchange and reverse osmosis system is considerably better than that produced by either system alone.
Dow is a large supplier of membranes that are used for reverse osmosis within the ultrapure water process. Other membrane suppliers include Nitto Denko and Toray. Korea-based Saehan has been gaining membrane market share. Equipment suppliers include GE Water, which participates through its acquisition of market leaders Ionics and Osmonics. Privately held Koch is also a player. Pall and Millipore contribute as well.
Ion exchange resins are used to remove mineral and heavy-metal contaminants from high-purity water. When minerals dissolve in water, they form electrically charged particles called ions. Certain natural and synthetic materials have the ability to remove mineral ions from water in exchange for others. Sybron Chemicals, Inc., a LANXESS Company, provides ion exchange resins for the ultrapure water market. Dow also manufactures ion exchange resins.
The selection of piping materials is critical to the performance of high-purity water systems because piping can contribute contamination. Corrosion from the piping material, biofilms and other organics are common problems associated with high-purity water storage and distribution systems. Georg Fischer is a supplier to the semiconductor industry and has expanded to include TFT/LCD displays and the solar industry as well. Harvel Plastics produces piping from a PVC compound that has been specifically formulated to reduce leachable contamination when exposed to ultrapure water environments. Saint-Gobain also provides high-purity material piping.
Maintaining the integrity of the high-purity chain requires valves and pumps designed for use in ultrapure water systems. Valve suppliers include Georg Fischer and Burkert Fluid Control. Saint Gobain and Teqcom Industries are also suppliers, and the latter also participates in the pump market. Other high-purity pump market participants include Grundfos, Pentair and ITT.
Instrumentation and controls are a major investment for the user of ultrapure water. The trend is toward continuous monitoring of critical aspects of the pure water system. In addition to particulate, it is common to measure pH, flow, resistivity, conductivity, temperature, pressure and contaminants such as total organic carbon (TOC). Conductivity, resistivity, and pH meters are normally located in the pretreatment system. Multiple TOC monitors are normally utilized. Pressure should be monitored at several locations, including those adjacent to critical components such as pumps and heat exchangers.
 |
Mettler Toledo provides instrumentation for ultrapure water systems. Swan Analytical Instruments and Analytical Technology are suppliers as well. Invensys, Emerson and Hach share the market also.
The largest user of ultrapure water is the semiconductor industry, and the most rapidly growing segment is flat panel displays. Purchases of ultrapure water systems for pharmaceutical applications continue to grow at a steady rate and will exceed $300 million worldwide in 2009. Within this sector, biotech is growing much faster than the total pharmaceutical UPW market. The world market for 2007 for these 3 industries can be seen in Figure 1.
Asia will have the largest market share in 2007. According to a new study by SEMI, Chinese semiconductor fab capital expenditures from 2006 through 2008 are expected to exceed U.S. $9.8 billion, which is larger than the total capital expenditure of U.S. $8.7 billion in the last five years from 2001 to 2005, according to a recent survey of major semiconductor manufacturers in China. Fab material spending is projected to grow steadily over the next three years. Fab material spending in 2007 may be as much as 58 percent higher than in 2006, since the new 300 mm capacity built in 2006 will be largely ready in 2007.
Figure 2 shows the 2007 geographical breakdown of the ultrapure water market. This breakdown includes ultrapure water used in the power industry, which does not utilize cleanrooms.
 |
The overall market for ultrapure water will grow 28 percent from 2007 levels to reach roughly $5 billion in 2010, as shown in Figure 3. This includes the power industry.
Robert McIlvaine is president and founder of The McIlvaine Company in Northfield, IL. The company first published Cleanrooms: World Markets in 1984 and has since continued to publish market and technical information for the cleanroom industry. He can be reached at [email protected].
Alpa Bagga is a market research analyst for The McIlvaine Company