Production Status of Nitrogen Trifluoride   
    
By Gong Haitao from Zhejiang Quhua Fluorine Chemical Co., Ltd., and Lu Chao from Zhejiang Juhua Calcium Carbide Co., Ltd.   

Nitrogen trifluoride (NF3) is a recently developed specialty gas for electronic industry, and is mainly used as etchant for semiconductor materials like polysilicon, silicon nitride and tungsten silicide, or as cleaning gas for CVD (chemical vapor deposition) chamber in semiconductor chip production and LCD panel. In CVD chamber cleaning, if compared with perfluorohydrocarbon, using NF3 can reduce about 90% of pollutant emissions, speed up the cleaning significantly and improve the cleansing equipment's ability by about 30%. Recently it has begun to replace perfluorohydrocarbon gradually.

Current status   

The demand for NF3 has grown rapidly in recent years. In mid-1990, the annual global consumption globally was less than 46 tons, but the figure rose quickly to 2 200 tons in 2004. To meet the growing demand, manufacturers worldwide are actively expanding their production capacity, and it is estimated that the capacity will continue to increase at an annual rate of 15% over the next few years.
    At present, the major NF3 manufacturers include Air Products, Boc Edwards and DuPont in the United States as well as Central Glass, Mitsui and KDK in Japan. Of these, Air Products is the largest worldwide and had announced at the end of 2007 that it would double the NF3 production capacity in its Ulsan base, South Korea to 1 000 t/a by 2009. Moreover, the total capacity of the company's NF3 unit in Pennsylvania, US has reached 2 200 t/a.
    As the second largest producer, Japan's KDK had a capacity of 240 t/a in late 2000 which rose to 2 150 t/a in February 2008 and is planned to be expanded to 2 700 t/a in 2009.
    China's major NF3 producers include China Nuclear Honghua Specialty Gases Co., Ltd. (Honghua Specialty Gases), Hubei Sanonda Tianmen Agrochemical Co., Ltd. and The 718 Research Institute of China Shipbuilding Industry Corporation. Honghua Specialty Gases, by adopting ammonium bifluoride electrolysis technology and DuPont's purification technology, can produce high purity (over 99.99%) products and have a production capacity of about 100 t/a now. In 2002, Sanonda invested RMB10.03 million and built a 24 t/a NF3 unit with the product purity reaching 99.99%, and sold all its products to large companies such as Japan's Toshiba and Showa Denko. NF3 produced by The 718 Research Institute has a purity of 99.999%, and the company's current production capacity is 300 t/a.
    China is the largest LCD manufacturer and exporter in the world at present. The rapid development of LCD is a major driving forcer of the demand for NF3, and it is estimated that from 2007 to 2010, China's average annual growth rate of NF3 demand will be maintained at more than 20%. However, at present, China's market of specialty gases for electronic industry is still dominated and monopolized by foreign enterprises.
    Compared with the international production giants, China's NF3 manufacturers do not have an influential brand in the industry, and almost all NF3 products are firstly exported, and then sold back to China after OEM processing. Domestic manufacturers should enhance China's NF3 international competitiveness through ways like expanding production scale, improving product quality and reducing production costs.