Semiconductor chip manufacturers use in their processes a variety of gases to pattern silicon wafers. After a number of wafers processed, the process chambers must be cleaned. Most of the gases used by the semiconductor industry are such as CF4, C2F6 and C3F8 named Perfluorocarbons, Nitrogen Trifluoride NF3 and Sulfur hexafluoride SF6. Perfluorinated gases, NF3 and SF6 are so-called greenhouse gases with a high global warming potential (GWP). Greenhouse gases in the upper atmosphere avoid the release of infrared radiation to the universe and reflect it backwards to the earth, thus increasing the earth’s temperature. The GWP of a gas is generally measured in 100-year time horizon and expressed in CO2 equivalents. The GWP value depends on the lifetime of the gas in the atmosphere and its ability to absorb radiation. As the molecular fluorine has no global warming potential, fluorine gas represents a beneficial cleaning gas alternative for CVD process chambers. Specialty gas mixtures for semiconductor use, which could be easily used as safe ‘Drop in’ in existing CVD equipment, were tested. It was demonstrated that modifications to the existing installed CVD tool base and related installation could be minimized. The proposed approach is, on the one hand, a cost effective solution for industrial semiconductor manufacturing, and on the other hand, lowering the amount of the used and emitted greenhouse gases. Two different fluorine gas mixtures as environmental friendly gases for CVD cleaning processes were tested under industrial production conditions as a replacement for SF6. This presentation describes the results of an industrial chamber clean processes using a fluorine gas mixture (Solvaclean®) to remove SiO2 residuals. In addition to this, the financial model using CO2 eq. calculation is shown, how fast a return on invest can be achieved, while applying this methodology.
