Ultrapure Water Filtration

Ultrapure/DI water is used in large volumes throughout the semiconductor manufacturing process. The specifications for the DI water quality have become increasingly stringent over the years and the filter technology has evolved to meet these requirements. 

Filters used to produce ultrapure water must do the following:

	Have low levels of extractables so the filter does not introduce contamination into the water system.
	Rinse-up with minimal water flow to 18 megohm-cm resistivity and single digit ppb TOC
	Final filters must be integrity tested/testable to assure performance at the stated micron rating
	Perform consistently from lot to lot
	Must retain captured contaminant even as differential pressures increase and not shed any media
	Be produced in a clean environment or cleanroom

Graver Product Selection

Product	Application Area
MBF™ or PMC™ Series filters	For pre RO applications, depth filters provide effective removal of sediments and particulates to prevent fouling of the RO membrane.  5 micron is most commonly used but finer filtration may be required based on water quality.  For longer filter life, the pleated PMC series can be considered.
ZTEC™ G or WaterTEC™ polyethersulfone membrane filters PMC™ or QMC™ Pleated polypropylene filters	DI resin trap – membrane or finely calendared melt blown filters trap any ion exchange resins that may be released from the resin bed.  0.2 or 0.45 micron recommended.
ZTEC™ E polyethersulfone membrane filters QTEC™ polyester track etch membrane filters	Pad prefiltration – highly consistent membrane filters provide protection of final point-of-use filters
ZTEC™ E polyethersulfone membrane filters VTEC® double layer polyester track etch membrane filters	Point-of-use cold DI – 0.03 micron ZTEC or 0.05 micron VTEC provide highly consistent performance at this critical process step.
TefTEC ™	Tank vents – hydrophobic PTFE membrane filters are recommended as tank vent filters to prevent the ingress of particulate or microbes into the stored water tanks.  If a more economical solution is desired, consider use of PMA absolute rated pleated polypropylene filters.
Gravex® Ion Exchange Resins	Low TOC, high purity Gravex ion exchange resins are available in anion, cation and mixed bed formulations.
ZTEC G / QXL / PMC / QMC / MBA	For recycling water after the tool, select the appropriate filter based on contaminants present in the water, before returning water to the DI process.