While semiconductor manufacturing is not considered a major contributor to global warming, our operations do emit greenhouse gases.

Minimizing greenhouse gases

Our direct emissions come from the use of Perfluorinated Compounds (PFCs) in our manufacturing processes, and emissions from burning fossil fuels to, for example, heat buildings. Also included in our direct emissions are Hydrofluorocarbons (HFCs) that escape during the maintenance of our air-conditioning systems. Our indirect greenhouse-gas emissions come from the use of purchased electricity, the production of which generates carbon dioxide (CO2). Emissions are reported as global warming in terms of tons of CO2 equivalents. The factors used for converting greenhouse gases to CO2 equivalents are given in the Third Assessment Report of the International Panel for Climate Change. In absolute terms, our direct CO2 emissions dropped in 2006 by 7% compared to 2005, form 44 to 41 kilotons. PFC emissions slightly decreased from 517 to 497 kilotons of CO2 equivalent, an absolute decrease of approximately 4%, while output increased by 15%. HFCs are greenhouses gases, but they're regulated by the Montreal Protocol, an initiative motivated by the contribution HFCs make to ozone depletion and not global warming. The use of ozone-depleting chemicals is prohibited in all our manufacturing processes and ozone-depleting refrigerants are replaced with non-ozone-depleting alternatives wherever possible and practical. We now only use ozone-depleting HFCs as coolants in our air-conditioning systems.

PFC emissions

PFCs are crucial to the production of high-quality semiconductor devices and make up approximately 50% of our company's direct and indirect global-warming emissions. We recognize the undesirable impact that PFCs have on the environment, and have joined with others in the semiconductor industry to seek ways to minimize their use. We have also implemented internal programs, such as EcoVision, which sets specific targets for reduction, aimed at limiting our PFC use. We have signed the Memorandum of Understanding in the US and the Memorandum of Agreement in Europe to voluntarily reduce the emissions of PFCs by 10% by 2010 compared to the 1995 baseline. We have already achieved this target in the US. The 10% goal for both regions will be sustained, despite a significant increase in wafer demand over time. When production growth is taken into account, the relative reduction will be over 75%.

PFC emissions in 1995 amounted to 365,982 tons of CO2 equivalents. Without the implementation of the PFC-reduction program and the ongoing miniaturization of our products, our PFC emissions would have increased by between 7 and 15% annually since 1995. On a normalized basis (emissions per square meter of silicon produced) the reduction since 1995 is close to 25%.

Most of our front-end operations are located in regions that are covered by the two voluntary agreements on PFC emission reduction. Two of our joint ventures, JNSC in China and SSMC in Singapore, are not covered. For these two, we have voluntary targets in place.

The European Memorandum of Agreement includes an obligation to report the progress of the PFC-reduction programs in an intermediate report. The members of the European Semiconductor Industry Association (ESIA) recently compiled the data and published an intermediate status report.

As we reach final implementation of the actions for process optimization and the use of alternative gases with a lower potential for global warming, we are entering a stage where abatement is one of the few remaining options for further emission reduction.

The European Union has recognized the semiconductor industry's proactive approach by granting an exemption in the so-called F-gases regulation. It is a voluntary agreement, so no ban on the use of PFCs for critical applications has been imposed on the semiconductor industry in Europe. We are, however, committed to looking for alternatives.

The impact of PFCs

The biggest impact semiconductor manufacturers have on global warming comes from their use of Perfluorinated Carbon (PFC) gases for cleaning and etching processes.

PFCs are very stable and absorb solar radiation very efficiently. This makes them a greenhouse gas that contributes to global warming. In fact, a single PFC molecule contributes 6,500 to 22,000 times more to global warming than a single molecule of carbon dioxide (CO2) does.

Unfortunately, there are currently no suitable alternatives to using PFC gases in semiconductor processes. There are, however, industry-wide efforts underway to minimize PFC use and to evaluate other approaches. In our own fabrication facilities, we have set targets for PFC reduction and carefully measure our emissions.