Beyond the Walls of Semiconductor Fabs: Energy intensity of high grade materials

The increasing semiconductor functionality relies on more complex integrated circuits with higher component densities. Miniaturisation and its implications on resource consumption in semiconductor facilities have been fairly well explored in a number of life cycle assessment (LCA) studies, which show that, in spite of the growing product complexity, resource intensities per product unit are gradually falling. However, increasingly advanced circuits demand high-purity materials, but the impacts of these trends on resource intensities in upstream manufacturing stages remain unknown. The growing use of high-grade materials may contribute to shifting the centre of manufacturing-related environmental impacts from circuit fabrication to raw material production stages. Unfortunately, cannot be seen in the existing LCA studies, which due to the lack of data are not able to quantify upstream and provide an incomplete picture of semiconductor environmental aspects. The paper illustrates the problem discussing energy demands for manufacturing ultra-pure wet chemicals. The paper examines the feasibility of using material price as a proxy for production energy intensity and proposes a framework for collecting chemical manufacturing related energy data. The authors suggest that by mapping the patterns of chemical usage and focusing on high-grade materials consumed in large volumes it is possible to reduce data collection efforts and improve the existing energy estimates