Production of High‐Resistivity Water at Texas Instruments

pends to a large extent upon the use of a water with unprecedentedly low levels of impurities. In many devices, the maximum allowable impurity levels are on the order of a few parts per billion. To make possible large-scale manufacturing operations involving such rigid specifications, extremely stringent control of all environmental factors is imperative. Present methods of water analysis are not adequate to determine rapidly the composition and relative proportions of all impurities in water when present in concentrations lower than 1 ppm. The difficulty of testing increases as the concentrations of impurities decrease. Previous ideas of water quality had to be abandoned as the water production engineers strove to keep up with the call for lower contaminant levels.