A typical semiconductor chipmaking plant can use enough water in one day to supply a medium-sized city.
A Tucson-based startup company says it can help chipmakers cut that by as much as half, with water-saving technology developed at the University of Arizona.
Environmental Metrology Corp. has developed an electrochemical system that can help chipmakers determine when a silicon wafer has been fully rinsed of contaminants from the manufacturing process.
The company recently announced it is seeking a buyer for the patented technology, which has been under development for seven years at the Semiconductor Research Corp./Sematch Engineering Research Center for Environmentally Benign Semiconductor Manufacturing at the UA, which is supported by a consortium of semiconductor firms.
The system also has undergone testing at the production plants of two major semiconductor manufacturers.
The company says that by helping chipmakers use just the right amount of ultrapure water for rinsing, they can save up to 50 percent on water usage, while avoiding defective chips and saving valuable manufacturing time.
The system, consisting of micro-sensor hardware and software, works by detecting the electrical impedance - the opposition of electrical current between the microscopic channels in the layers of a semiconductor chip, said Doug Goodman, chairman of Environmental Metrology Corp. and chairman/CEO of Ridgetop Group Inc.
"It detects when you've adequately rinsed the wafer," Goodman said. "The initial inclination of most people is 'more is better,' so they keep the water on too long."
Multiplied by many separate manufacturing steps, that water use adds up.
One chipmaking plant can use from 2 million to 4 million gallons of ultrapure water per day, roughly equivalent to the water usage of a city of 40,000 to 50,000 people, said Farhang Shadman, director of the UA semiconductor research center and a Regents professor of chemical and environmental engineering and optical sciences.
Goodman and Shadman co-founded Environmental Metrology in 2003 with Bert Vermeire, a UA chemical engineering Ph.D. who is now an associate professor at Arizona State University.
The company developed the technology with a series of federal Small Business Innovation Research grants totaling about $2.5 million, Goodman said.
The testing by the chip manufacturers, whose names were not disclosed, led to publication of a case study in Elsevier's Microelectronic Engineering Journal in late 2008.
In 2009, the sensor system won an Editor's Choice Best Product Award from Semiconductor International magazine - awards that usually go to "very large instruments from very large companies," Shadman noted.
The technology has caught the attention of members of Semiconductor Research Corp., a consortium that includes Advanced Micro Devices, Freescale Semiconductor, Hewlett-Packard, IBM, Intel and Texas Instruments.
"I think our companies are pretty excited about the results so far," said Dan Herr, director of nanomanufacturing sciences for Semiconductor Research Corp.
"For the companies, it's not only good for the environment, it's good for their bottom lines," Herr said, noting that less water usage means less waste that must be processed to meet environmental standards.
Goodman said Environmental Metrology is in talks with several semiconductor toolmakers and chipmakers to sell or license the residue-sensing technology.
The technology could be used in standalone sensor devices along the manufacturing chain, or incorporated into the larger silicon wafers that are eventually cut up into individual computer chips, Goodman and Shadman said.
"It's a huge opportunity," Goodman said.
He noted that the chipmaking "tool" market comprises some $25 billion of an overall semiconductor market forecast to reach $290 billion in sales this year, according to the research firm Gartner.
Shadman said he expects interest to grow in the residue sensor after the company finishes a wireless version of the device.
That wireless research is being conducted at ASU, where Vermeire, former Ridgetop chief technology officer, is an associate research professor of electrical engineering.
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