DI water, or deionized water, is water that has had mineral ions removed from it in order to purify it. It is formed by exposing water to an electrically charged resin, which attracts these ions and binds them. This removes those minerals from the water. With the exception of bacteria, viruses, and ions integral to water such as hydroxide, all impurities are in this way removed from the water. These minerals include, most commonly, sodium, copper, iron, chloride, and calcium.
DI water has found an important place in semiconductor manufacturing. In semiconductor devices and integrated circuits, a clean, low contaminant environment is essential to production and development. This new technology of purity in water is a huge step for the semiconductor industry and maintaining a high standard of cleanliness. The low level of salts and minerals means that microorganisms are unable to live in this environment, resulting in their deaths. In constructing and developing semiconductors, it is important that microorganisms cannot survive and cause defects.
DI water also has a use in liquid-cooling applications. Most commonly, tap water is utilized for this. Due to its impurities, there are some applications that tap water cannot meet in the way that DI water does. Different electrical and chemical properties allow DI water to deal with cooling applications involving sensitive electronics or the microchannels of a circuit. The nature of DI water also means that there are no minerals blocking the flow of coolant, as well as negates the risk of static build up resulting in permanent damage to the electronics. Coolant using this type of water is also very corrosive, however, so materials must be corrosive-resistant in order to avoid this. Thanks to its scarcity of ions, DI water eliminates many problems normally encountered with standard water.
DI water is used in a number of different industries and applications beyond semiconductors, including lasers, cosmetics, medical equipment, pharmaceuticals, chemical processing and even food processing. Due to its lack of impurities, DI water is also said to have health related attributes, though drinking it is not necessarily health stimulating as the ions removed from it are also found in food.
DI water is a reliable fluid used in many different systems and equipment, whether for cooling, sterilization, or more. In cooling systems, DI water allows for a smooth operation free of leaks and defects, while in semiconductors, this type of water is able to kill off tiny microorganisms to keep defects out of the semiconductor device. These applications and industry uses are all able to run reliably and stably with the help of deionized water.