Ultrapure water system & Deionized Water system
Ultrapure water is a commonly used term in the semiconductor industry to emphasize the fact that the water is treated to the highest levels of purity for all contaminant types.
The most widely used requirements for UPW quality are documented by:
ASTM D5127 - Standard Guide for Ultra-Pure Water Used in the Electronics and Semiconductor Industries.
SEMI F63 - Guide for ultrapure water used in semiconductor processing.