Chipmakers plan for future with H₂O reclaim processes

07/01/2001

Meg Villeneuve

GRESHAM, OR/SANTA CLARA, CA—The threat of water shortages throughout the country is causing semiconductor fabs to take a step back and evaluate where their water comes from and how it can be preserved.

The long-term goal for many companies is to decrease the amount of water being taken from the municipalities where the fabs are located.

Many fabs are initiating one of two types of water treatment. The first, recycling, is the use of water from one process to the same process, and the second, reclamation, is when industrial or processed wastewater is collected internally and then treated and reused in a different industrial system.

When chipmaker LSI Logic built its chip plant in Gresham, OR, the company preplanned for a wastewater recycling system. "LSI's fab was designed to segregate chemical wastewater streams, which makes the effort to reclaim a bit easier," says Mike Bennett, principle facilities engineer for LSI.

Though still in its test phases, LSI's wastewater reclaim process has been able to recover some 80 percent of the water. "We are recycling the largest volume stream that has traces of all the chemicals used in the plant. Once the water goes through several processing steps it's re-introduced into the front end of the UPW (ultrapure water) system," Bennett says.

Also, at an intermediate stage of the treatment process, the water is sent to cooling towers and scrubbers. "We feed it into the major water consumers at the plant," Bennett says.

The test system being used at LSI's plant was developed with US Filter. The company is currently constructing a larger-scale version of the system and says its design is 30 percent complete. LSI expects to have it up and running in 2-3Q of 2002.

For its part, Intel Corp. (Santa Clara, CA) established a water team, which was created to evaluate industrial water management. Intel's Water Program Manager, Tom Cooper, is an active member of the team. "The subject of water conservation is not a new thing for Intel. [We] are just working on new ways of reclaiming water," Cooper says.

Cooper says Intel is looking at tools that are efficient, including those that are able to decrease water usage. "Take a wet bench sink that wafer boats go into, for example. [Originally] the sinks were bigger than the wafer boat and they didn't have to be. Now it's the same size as the boat, therefore it uses less water," Cooper says.

From 1998 to 2001, Intel predicts that it has saved more than five billion gallons of water. And even when its fabs go from eight-inch to twelve-inch wafers, the company does not expect water consumption to increase.

In 1995, International Sematech did a survey that showed many fabs were trying to come up with new ways to reclaim
ecycle water. "Fabs are trying to get more use out of their water," says Bob Donovan, process engineer at Sandia National Labs. International Sematech was unavailable for comment.

It makes sense to try to re-use the water within the fab once its been processed instead of feeding it back into the municipal source. "The water being discharged by the fab is far more superior because the impurities are long gone," Donovan adds.