Purpose The life cycle assessment of silicon wafer processing for microelectronic chips and solar cells aims to provide current and comprehensive data. In view of the very fast market developments, for solar cell fabrication the influence of technology and capacity variations on the overall environmental impact was also investigated and the data were compared with the widely used ecoinvent data. Methods Existing material flow models for silicon wafer processing for microelectronic chips and solar cells used for engineering and planning formed a starting point for this analysis. The models represent an average of widely used processes and associated process equipment. The resulting input/output tables formed the data basis for the life cycle assessment. This is a cradle-to-gate investigation, consisting of primary gate-to-gate data for wafer processing. The upstream processes of the necessary inputs were supplemented with data from ecoinvent v2.0. Subsequent manufacturing steps, utilization, and waste disposal of the final products were not included. The software used for creating the inventory and impact assessment was Umberto version 5.5. The Impact 2002+ method was applied for impact assessment. Results For both semiconductor and solar cell fabrication, energy consumption and upstream chemicals production are most relevant for the overall potential environmental impact when only the gate-to-gate processes are considered. The upstream process for wafer production is dominant in solar cell fabrication, but exerts little influence on semiconductor fabrication. In the case of semiconductor fabrication, a comparison with the present ecoinvent dataset "wafer, fabricated, for integrated circuit, at plant" shows large differences. Conclusions In the case of silicon solar cells, the results of this study and the ecoinvent data are very similar and the impact of different fabrication processes appears to be minor.

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Polymer processing is an energy-intensive industry. The plastification of polymers requires a high volume of electric power for thermal energy. Electricity based power is the common form of energy in polymer processing and provides obvious potential for a reduction in energy use and costs. Measures to avoid productionbased conversion losses, total conversion and transportation losses in energy used all have social, national, economic and business relevance. A bottom-up evaluation of four different production factories in this study assesses the potential for energy use improvements. The resulting theoretical assessment suggested that reducing primary energy demand is the most powerful target for reducing energy intensity in the polymer industry followed by the introduction of improved technologies to raise energy efficiency. The transferability of the conclusions was supported by the comparison between two different geographic locations for polymer production in Germany and Western Australia. The findings of this research suggest potential in their use in 'green' decision-making in the plastics industry.

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In semiconductor and crystalline silicon solar cell fabrication, volatile organic compound (VOC) abatement is state of the art and obligatory in many countries. Thermal or catalytic oxidation is used as the preferred reduction technique in this field. Because of low concentrated exhaust gas, oxidation needs additional energy which is not to be ignored. Against the background of resource depletion, the question arises whether, from an environmental point of view, treatment is more beneficial than the direct release of emissions. The overall potential environmental impact of several scenarios has been investigated using a method based on Life Cycle Assessment (LCA). The results show that below an exhaust concentration of 600 mg/m 3 for semiconductor fabrication and below 1500 mg/m 3 of nontoxic solvents for solar cell fabrication, exhaust conditioning causes a greater potential environmental impact than the direct release without any treatment.