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Ultrapure Water for Electronics

IC is an efficient analytical technique that can determine quickly both trace and major constituents of a wide variety of process contaminants in the semiconductor, disk drive, and plating industries. This technique provides a convenient means of quantifying common inorganic anions and cations, certain organic additives, transition metals, polyvalent ions, and organic chelating agents. With online IC process monitoring, these components can be determined quickly at low parts per trillion levels for immediate remediation steps.

Trace Analysis Techniques

It is estimated that a typical power plant circulates over one billion gallons of water each year. How can power plants be sure that the water they use is as pure as it can be? AutoPrep is a technique developed by Dionex to combine preconcentration and automatic calibration to generate standard curves and eliminate human error, providing an increased level of accuracy at trace levels in an easy-to-use format. AutoPrep is a term that describes a series of automated steps used to prepare samples online.

Why AutoPrep?

  • Simplifies trace analysis
  • Contamination free, because standard calibration and sample preparation is performed online
  • Lower detection limits—less than 5 ppt
  • Sample calibration and concentration is automated
  • Fewer errors, improved reliability
  • Lower labor costs


The water used in the manufacture of semiconductors and other modern electronic components must be extremely pure. Contaminants can remain behind as water used to clean semiconductors evaporates, and form highly corrosive salts. The production of UHPW includes deionization to remove strong acid anions such as chloride and sulfate. Deionization cartridges used to remove ions need to be replaced periodically. When these deionization cartridges begin to fail, one of the first ions to break through the cartridge and contaminate the water is silicate.

Silicate can break through even while electrical resistivity yields a reading of 18 MΩ-cm. Therefore, silicate is a good early indicator of cartridge depletion. Changing deionization cartridges when silicate first appears can help prevent manufacturing failure of expensive electronic components. The sooner silicate can be measured, the earlier process failure can be determined. This is where trace analysis is important. Dionex invented AutoPrep in order to eliminate the possible introduction of contaminants during standard and sample handling. The combination of an RFIC system and AutoPrep reduces sources of contamination and error, assuring accurate trace analysis.