Desorption characteristics of isopropanol (IPA) and moisture from IPA vapor dried silicon wafers

In order to estimate the cleanliness of wafer surfaces cleaned and dried with various procedures, the outgassing from these wafer surfaces was analyzed by highly sensitive atmospheric pressure ionization mass spectrometry (APIMS). In particular, the desorption of isopropanol (IPA) and moisture from wafers after IPA vapor drying was investigated by introducing the desorbed gases from wafer surfaces into APIMS. It is shown that desorbed trace impurities, the amounts of which are as small as 1/10 of a monomolecular layer of adsorption, were qualitatively and quantitatively detectable under these experimental conditions. As a result, it was confirmed that the desorption behavior is influenced by the surface condition of the wafers, caused by the wet chemical processes and the drying methods.>