An extraction method of micro-contaminants detrimental for silicon (Si) devices and its impact on clean technology are elaborated to focus on upgrading device performances. Deleterious metal impurities on wafer surfaces such as Fe, Cu, Ni and Al are analyzed using an improved pack extraction method (PEM), in which sample wafers were enclosed in a cleaned teflon bag with aqueous acid solutions. Upon the extraction of impurities, three types of solutions [(I) HCl/H2O, (II) HF/H2O and (III) HF/HNO3/H2O], were successively replaced one after another in the cleaned teflon bag, resulting in measuring impurities on oxide surfaces, oxides and SiO2-Si interfaces, separately. The monitoring of these harmful impurities helps feed back to reduce the impurities in device manufacturing processes.
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