Reduce / Reuse / Recycle

October 9, 2003

 

Seiko Epson Starts Closed Recycling of HF Semiconductor Wastewater

Keywords: Chemicals Environmental Technology Manufacturing industry Policy / Systems Reduce / Reuse / Recycle 

Seiko Epson Corp., a Japanese electronics manufacturer, has developed a technology to generate high-purity fluorite, or calcium fluoride (CaF2), from wastewater containing hydrofluoric acid (HF) that was used for the manufacture of semiconductors, as part of its efforts to promote "zero-emissions". This has made closed recycling possible, in which HF-based waste liquid is restored to the level where it can be used again in the semiconductor manufacturing process.

The company has been working to achieve a higher level of recycling by not only recycling 100 percent of the wastes generated as a result of its business activities but also by eliminating waste creation itself. As part of these efforts, the company had been pursuing research on closed-recycling technology for HF recovery at its semiconductor manufacturing plants for about two years. It has finally succeded, a first in the semiconductor industry.

In the semiconductor manufacturing process, HF is used as an etching agent to remove silicon oxide film, and this generates HF-based waste liquids containing impurities. The liquids are reused after being treated for HF recovery. The recovered HF, however, has not been pure enough for use in the next round of semiconductor production; and instead, it was normally used by steel-makers to treat the surface of stainless steel, etc..

With the new technology, Seiko Epson was able in mid-August 2003 to start recovering high-purity fluorite from HF-based wastewater generated at its manufacturing facilities. The recovered fluorite is used as a raw material for HF. This HF can be used for another round of semiconductor manufacturing at the same facilities. The results of this techology will be a reduction in the amount of fluorite to be mined for HF production as well as the elimination of about 80 tons of wastes (low-purity fluorite) a year.



Posted: 2003/10/09 07:30:53 AM
Japanese version

 

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