In many semiconductive material fabrication processes it is desirable to utilize deionized and degassed water. The deionization is used to remove elemental contaminants from the water and can increase a resistance of the water to from about 200 kohms to about 1800 kohms.
The degassification is used to remove carbon dioxide from the water. Carbon dioxide can influence a pH of the water. The degassification also, however, removes other gasses from water besides carbon dioxide. Such other gasses can include, for example, oxygen and nitrogen. An example unit for degassifying water is a Liquicell unit (available from Hoechst Celanese Corp. at 13800 South Lake Drive, Charlotte, N.C. 28273), which removes gasses via a gas permeable membrane.
The deionization and degassification of water is typically done on a system-wide scale in a semiconductive material fabrication plant. Accordingly, all water supplied to the various fabrication units of the plant is degassed and deionized.