Nitrogen Triflouride

A lot of nitrogen triflouride is used in manufacturing CPUs (75%) and LCDs (25%). 4000 tons per year in fact. Michael Prathner, at the Environment Institute at UC Irvine claims that nitrogen triflouride is 17,000 times more potent as carbon dioxide as a greenhouse gas. The greenhouse impact of 4000 annual tons is larger than perflourocarbons (PFCs) or sulfur hexaflouride (SF6) emissions from industrialized nations. Nitrogen triflouride lasts a long time too. This synthetic chemical survives in the atmosphere for 550 years! Unfortunately, nitrogen triflouride is not included in the Kyoto target list of substances that should be reduced. The industry states that about 2% of the 4000 tons (that’s 80 tons per year) gets out. That sounds like a lot.

Nitrogen Triflouride: Required Chemical in LCD Production

It’s not surprising that chemicals that are not very friendly to the environment is used to manufacture CPUs and LCDs. A lot of chemical-based etching required in silicon wafers as well as etching thin-film-transistors (TFTs) on LCD glass. There are technologies currently being developed to at least reduce the amount of chemicals and cleaning agents required to etch TFTs. One of those technologies is ink-jet printing and Sharp was one of the first to use the technology to manufacture color filters. According to Wikipedia regarding nitrogen triflouride’s greenhouse gas statistics:

NF3 is a potent greenhouse gas, with a global warming potential (GWP) 17,200 times greater than that of CO2 when compared over a 100 year period. Its GWP would place it second only to SF6 in the group of Kyoto-recognised greenhouse gases, although NF3 is not currently included in that grouping. It has an estimated atmospheric lifetime of 740 years, although recent work suggests a slightly shorter lifetime of 550 years (and a GWP of 16,800).

Industrial applications routinely break down NF3, whereas the regulated compounds SF6 and PFCs are released. Although the impact of NF3 is difficult to project, based on 2008 production levels of 4000 tons, NF3 could prove to be more significant than PFCs or SF6, and greater than that of the largest coal-fired power stations.

NF3 was originally chosen in about 2000 as an environmentally preferable substitute for perfluorocarbons to clean the vacuum chambers where integrated circuits were made. About two-thirds of the PFCs escaped into the atmosphere; NF3 was less likely to escape into the air. In 2008, about three-quarters of the chemical is now used to manufacture computer microchips; the rest is used to make LCD panels. World production of NF3 is expected to reach 8,000 tons a year by 2010. Currently at least 2% is ultimately released into the atmosphere; perhaps substantially more, but there is not good independent data about releases, nor measurements of atmospheric concentration.

Source: Tree Hugger

[tags]Nitrogen Triflouride, Greenhouse Gas, CPU Manufacture, LCD Manufacture[/tags]

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