Date: Apr 29, 2004 Author: Amit Asaravala Source: WIRED.com (
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by Amit Asaravala
For years, green tea has been believed by some to lower cholesterol, prevent rheumatoid arthritis and even stave off cancer. Now scientists think the warm green stuff has yet another benefit: the potential to save hard-drive manufacturers millions of dollars.
A team of researchers based in Tucson, Arizona, announced Monday that a study of the use of green tea extracts for polishing the magnetic heads in hard-disk drives has yielded a compound that works three to four times faster than conventional compounds. If the findings can be reproduced in an industrial setting, the compound could reduce the cost and environmental impact of hard-drive manufacturing, the researchers said.
The study was funded by a $100,000 grant from the National Science Foundation, awarded under its Small Business Innovation Research program.
"It's an exciting new area of chemistry," said John Lombardi, lead researcher on the project and president of Ventana Research. "Our original drive was to develop a (polishing) fluid that was biodegradable. But as we got deeper into developing the compound, one thing we discovered is that it could increase the efficiency of the magnetic read-write manufacturing process."
The hard-drive manufacturing industry relies on special polishing compounds, or slurries, to ensure that the magnetic heads responsible for reading and writing data on a hard drive have virtually no imperfections on their surfaces. A bump or particle that is just 1 nanometer in height could cause the head to scratch the disc-like platter that it sits above, destroying the data on the hard drive.
Manufacturers add the slurries to the hard-drive heads while they are being polished. Although the specific ingredients in the slurries are closely guarded secrets, they typically work by attracting and containing the tiny ceramic particles that are created during the polishing process. After a certain amount of time, the slurry is washed away and disposed of according to various regulations on the chemicals that it contains.
With the compound created by the Arizona team, the particles would be attracted by tannins in the green tea extract. The ability of tannin to bind readily with ceramics is the same principle that causes green tea to leave stains on mugs and teapots. The researchers hope the high availability and biodegradability of green tea will make it a less-expensive option for drive manufacturers.
The researchers also said they believe their discovery could be applied to all sorts of electronics-polishing applications, known as chemical mechanical planarization. "Although John's (Lombardi) work is in the magnetic media industry, I think the compounds themselves have far-reaching implications for the semiconductor industry," said Srini Raghavan, a professor of materials science and engineering at the University of Arizona.
Raghavan and a third team member, Pace Technologies CTO Don Zipperian, assisted Lombardi with the study. Pace Technologies sells chemicals and other products for microsurface finishing.
It's too soon to tell how much of an effect the team's research will have on the $406 million slurry industry. But Lombardi said the study has already received a good deal of interest from one company that he declined to name.
A spokesman for Cabot Microelectronics, the leading manufacturer of slurry compounds, said the company had not yet had a chance to look at the study and therefore could not comment on its impact.
The next step for the researchers is to quantify the environmental impact of the green tea compound in relation to other slurries and to develop it for commercial use, said Raghavan. Part of that development might be funded by a phase II grant from the National Science Foundation, he said. If the group's application is accepted, the phase II grant would provide the team with $500,000 over two years to develop the compound into a commercially viable product.
Approximately 40 percent of businesses that complete the phase II process go on to produce successful products, according to a National Science Foundation estimate.
