C&EN logo The Newsmagazine of the Chemical World
Home Current Issue ChemJobs Join ACS
Support
Latest News
Business
Government & Policy
Science/Technology
Careers and Employment
ACS News
topics
   
Support
 
Support
How to log in
Contact Us
Site Map
   
About C&EN
About the Magazine
How to Subscribe
How to Advertise
Chemcyclopedia

Latest News RSS Feed

latest news RSS feedWhat is this?

   
Join ACS
Join ACS
  Cover Story  
  June 27, 2005
Volume 83, Number 26
p. 23

GAS DELIVERY

  Arguing Over The Safety Of Fluorine  

  JEAN-FRAN?OIS TREMBLAY, C&EN HONG KONG  
   
 
 

Fluorinated compounds are used to clean critical instruments like chemical vapor deposition (CVD) chambers in semiconductor and liquid-crystal display (LCD) plants. At display plants, fluorine is both an expensive raw material and a challenging one because of toxicity and reactivity concerns.

Early on, the electronics industry opted to get its fluorine from hexafluoroethane. But the material is a greenhouse gas, and its use has faded. For nearly 10 years, the standard method of fluorine delivery to the CVD chamber has been nitrogen trifluoride, which is decomposed into fluorine and nitrogen immediately before use. The NF3 is made at a separate location.

Earlier this month, BOC Edwards announced that it is launching an on-site fluorine generator specially designed for the LCD industry. Noel Leeson, the firm's president of electronic materials for Asia, says safety and reliability are ensured by adding what seems like too many safety features to the machines.

Air Products & Chemicals, the largest supplier of NF3 to the electronics industry, does not offer such generators. To meet the demands of flat-panel makers, it recently expanded its facilities in the U.S. and is building an ammonia plant in South Korea, according to Corning F. Painter, regional vice president for electronics in Northeast Asia.

Painter warns that it is too hazardous to deliver fluorine gas to a CVD chamber. The best piping systems can leak, and there is a danger in storing the hydrogen fluoride that the generators require. The company's data show that fluorine is 2.5 times more toxic than chlorine gas. "F2 is also very reactive, so it requires special considerations to contain it," he adds. NF3, by comparison, is no more harmful than mothballs, according to Air Products.

BOC's Leeson says Air Products' response is understandable given that it has been investing large sums of money to expand its nitrogen trifluoride facilities. But he notes that the delivery of nasty gases to electronics manufacturers is commonplace, silane being a prime example.

Fluorine has been generated on-site for years for customers in the chemical and surface treatment industries, Leeson says. He acknowledges that an on-site generator in the electronics industry would likely be located several hundred meters from the CVD chambers. But the gas is delivered in a dual containment pipeline, with the inner pipe--about half an inch in diameter--carrying fluorine at low pressure, and the outer pipe carrying nitrogen at a higher pressure. He adds that in the unlikely event of a burst pipe, the generator will shut down, and only the fluorine contained between two auto-shutoff valves will leak out.

Leeson says fluorine delivery is a major focus for BOC Edwards. "In 20 years, you will see that every semiconductor and LCD plant will have its own on-site fluorine generator," he predicts.

MORE ON THIS STORY
THINNING FLAT PANELS
Materials suppliers are thrilled by the flat-panel industry's growth, but are under pressure to trim back on costs

FORGING THE WAY TO HIGH-K DIELECTRICS
Numerous electronic chemical producers are ready to supply hafnium-based materials

ANCILLARY CHEMISTRY
High-K Dielectrics Require New Etching Techniques

DATA STORAGE IN 3-D
Holographic data storage has made enormous technical advances, but still awaits a market

 

     
  Chemical & Engineering News
ISSN 0009-2347
Copyright © 2005
 


Advertisements
Visit ChemSW
Visit Prous Science
Visit Dow Corning
Visit Applied Biosystems
Visit Beckman Coulter
Advertise Here
Related Stories
Electronic Chemicals
[C&EN, Jun. 28, 2004]
Making Fat Profits In Flat Screens
[C&EN, Jun. 28, 2004]
Electronic Chemicals
[C&EN, Jun. 23, 2003]


 
E-mail this article
to a friend
Print this article
E-mail the editor