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NEC Electronics Reduces Emissions of PFCs by 21% against Previous Year
KAWASAKI, Japan, June 23, 2008
NEC Electronics Corporation (TSE:6723) today announced that it has succeeded at reducing emissions of the greenhouse gas PFCs by 21% against last year. This is a 30% reduction from the company's highest-ever emission levels in 2004.
NEC Electronics successfully reduced emissions of perfluorocarbons (PFCs)[Note 1] - a type of greenhouse gas - to 760,000 tons-CO2[Note 2] in 2007 - which is 80% of 2006 levels. A PFC is a chemical in which all the hydrogen (H) in a hydrocarbon (C-H) has been replaced with fluorine (F). The reduction in PFC emissions was achieved mainly by (1) reducing the amount of PFC used in film processes by designing efficient usage conditions for PFCs; and (2) promoting the research and use of alternative gases. The company is now working to further reduce emissions in 2008 and beyond by (3) introducing exclusive abatement systems that break down PFCs on its production lines from fiscal 2007 to 2008.
NEC Electronics has set the target of reducing PFC emissions to 90% of 1995 levels - 529,000 tons-CO2 - by 2010. This translates to a target emission level of 476,000 tons-CO2 or lower by 2010. The present measures exceed this target, and it appears possible that the company will be able to greatly reduce its emissions.
In recent years, emissions of greenhouse gases that impact to global warming, such as carbon dioxide (CO2) emitted through the combustion of petroleum, coal, and other fossil fuels, have become a focus of society-wide attention. The Kyoto Protocol, which went into force in 2005, specifies a number of greenhouse gases in addition to CO2, including methane gas (CH4), which is produced by such sources as cattle digest and rice cultivation; nitrous oxide (N2O), which is contained in livestock waste and farmland soil; and hydro fluorocarbons (HFC), which are widely used as a replacement for chlorofluorocarbon (CFC) refrigerants. Although the Protocol also specifies PFC, which is used in the production of semiconductors and other products, as a greenhouse gas, it is not widely known because it only comprises about 2% of all greenhouse gases. However, PFCs have a global warming potential that is 5,000 to 12,000 times greater than CO2. In other words, PFCs have a large environmental impact, and there is a growing awareness that reducing these emissions is an effective way to prevent global warming.
Semiconductor production chiefly consists of two processes: wafer processing, in which electrical circuits are formed on a silicon wafer; and chips assembly, in which silicon chips are sealed in packages. PFC is used in two processes of the wafer processing: deposition, in which thin films of insulation, metals, and the like are formed on the surface of the silicon wafer; and etching, in which the insulating or metallic film is etched or scraped away. One widely used deposition method is chemical vapor deposition (CVD). In CVD process, when plasma is generated over the surface of the silicon wafer and a film is formed, the residue of the raw materials adheres in the process chamber of the manufacturing equipment. PFC is then used to break down and remove this residue. PFC is also used as a gas raw material in the etching process. PFC is broken down into carbon and fluorine in the process chamber of the manufacturing equipment; because this fluorine reacts well with the insulating and metallic film of the semiconductor, it is an essential chemical for the production of these products.
Within the semiconductor industry, the World Semiconductor Council (WSC) set a target in April 1999 of reducing emissions of PFCs and other chemicals to no more than 90% of 1995 levels by 2010. Since then, the each companies in the industry have been working to meet this target.
In 1997, when NEC Electronics was the NEC Semiconductors Group, the group created a cross-functional PFC Task Force whose mission included analyzing trends in the use of PFCs and the effects of their use. The task force enhanced initiatives to reduce PFC emissions. Simultaneous to the WSC, the company set a target to reduce emissions to 90% of 1995 levels by 2010, and has been working toward this target to the present day. As production volumes increase, however, so do emission volumes. As a result, by 2004 PFC emissions had more than doubled from 1995 levels, to greater than one million tons-CO2. The company responded by serious study of measures to reduce PFC emissions even in the face of increasing production volumes. After implementing a wide range of measures, the company succeeded at greatly reducing its levels of PFC emissions.
Below are measures carried out by NEC Electronics.
- (1) Reduce amounts of PFC used
NEC Electronics repeatedly improved the usage conditions of PFCs, in order to minimize the amounts needed to remove raw-material residue from the deposition process. Through these efforts, it has succeeded at reducing the amount of PFC needed by as much as around 40% of conventional methods. NEC Electronics will reduce its use of PFCs by deploying the results of these experiments to other NEC Electronics fabs.
- (2) Introduce alternative gases
NEC Electronics had mainly used C2F6 during the production process. C2F6 has a global warming potential of 11,900. The company is replacing this gas with C3F8, which has a global-warming potential of 8,600.
- (3) Introduce exclusive abatement system on production lines that breaks down PFCs
There are several types of PFC abatement system, including combustion, heater, and catalytic. NEC Electronics is introducing a combustion PFC abatement system with the support of the New Energy and Industrial Technology Development Organization (NEDO). In fiscal 2007, the company introduced a total of six units on the 6-inch lines of NEC Semiconductors Kyushu Yamaguchi's Yamaguchi fab, and NEC Semiconductors Kansai fab. The units went into production operation this year. In fiscal 2008, the company will introduce the units on the 8-inch lines of NEC Semiconductors Kyushu Yamaguchi's Kumamoto Kawashiri fab, and NEC Semiconductors Kansai fab, and bring them into production operation this year.
Through these measures, NEC Electronics makes sure to meet its target of reducing PFC emissions to 90% of 1995 levels - 529,000 tons-CO2 - by 2010, translating to a target emission level of 476,000 tons-CO2 or lower. The company is also acting now to continue reductions with an eye beyond 2010. As a dedicated manufacturer of semiconductors, NEC Electronics will also enhance its environmental management in order to win the trust of society.
At the International Semiconductor Environment, Safety & Health (ISESH), organized by the Japan Electronics and Information Technology Industries Association (JEITA) and to be held from June 23 to 26, 2008 in Sapporo, Hokkaido, NEC Electronics will be giving a presentation titled "About our difficult challenge to adopt the abatement system for existing lines," in which it will present its initiatives to reduce greenhouse gases.
A PFC is a chemical in which all the hydrogen (H) in a hydrocarbon (C-H) has been replaced with fluorine (F). Its global-warming potential is 5,000 to 12,000 times greater than that of CO2.
A ton-CO2 is a unit of conversion for greenhouse gases. It uses a method of calculation determined by the Intergovernmental Panel on Climate Change. It is calculated by multiplying the Global Warming Potential (which is the strength of the global-warming effect compared to CO2) by the volume of gas emitted into the atmosphere.
About NEC Electronics
NEC Electronics Corporation (TSE: 6723) specializes in semiconductor products encompassing advanced technology solutions for the high-end computing and broadband networking markets; system solutions for the mobile handset, PC peripheral, automotive and digital consumer markets; and multi-market solutions for a wide range of customer applications. NEC Electronics Corporation has subsidiaries worldwide including NEC Electronics America, Inc. and NEC Electronics (Europe) GmbH. More information about NEC Electronics worldwide can be found at www.necel.com.
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