Dr. Andreas Jantschak | Environmental Management, NXP Semiconductors Germany GmbH, Site Hamburg
Bio filter Technology: An innovative and highly cost-effective system for removing VOCs
Abstract – The Bio filter system is a highly cost-effective system with excellent efficiency for VOC treatment. For our site, this abatement concept is the best technology for environmental protection and meets all the requirements of German and European law. The application of this new technique in the semiconductor industry was an interesting challenge for the project team at NXP Semiconductors Hamburg.
New legal limits for VOC emissions (Volatile Organic Compounds) in Europe and Germany and the NXP Environmental policy make it necessary to treat the exhaust air from production processes at the NXP Semiconductor site in Hamburg. The new German legal limit for VOC concentration in exhausts is 50 mg/m3. Because various systems are available on the market, the task of a local project team was to find a cost-effective and applicable technology for NXP Hamburg.
After conducting comprehensive investigations into all available abatement tools adapted to the VOC data in our semiconductor fab it became obvious that there were only two technologies suitable for NXP: Regenerative Thermal Oxidation and the Bio filter system.
Regenerative Thermal Oxidation (RTO) is the standard system in the semiconductor industry. In RTO, the VOCs are converted into carbon dioxide (CO2) and water (H2O) and the by-products nitrogen dioxide (NOx) and carbon monoxide (CO) by a burning process using natural gas.
In the Bio filter system VOCs are adsorbed onto a natural filter material and are completely biodegraded by microbes to CO2 and H2O. No harmful by-products are created.
The team in Hamburg fully evaluated the two options. Not only is the Bio filter system around 10 times less expensive to run, but in contrast to thermal oxidation, the natural oxidation in a Bio filter produces no surplus CO2 and no critical burning by-products such as CO and NOx. In addition, the contribution to CO2 air pollution is significantly lower than that of the RTO. Although used in many industries such as food and automotive, this process is relatively new to the semiconductor industry so the team performed a 3-month pilot to ensure they made the right decision.
By the end of 2007 Hamburg was running two Bio filter systems; one for the IC lab and the other for the Discretes fab (BL GA). Due to these two systems the VOC emissions for NXP Hamburg was reduced by more than 90%.
The Hamburg Bio filter project was presented to the German Semiconductor Association ZVEI as a best practice and since then the site has hosted visits from several different companies/industries (e.g. Daimler, Reemtsma, European food industry) wanting to see our bio filter systems in operation and to learn from our experiences with this technology.