Corrosion characteristics of metallization systems with XRF

Summary form only given. The effects of chlorine levels on corrosion for various metallization schemes used in a double-metal submicron CMOS process are discussed. Wafers were etched in Applied Materials 8330 using BCl₃/Cl₂ chemistry. X-ray fluorescence spectroscopy (XRF) was used to determine the chlorine (Cl) and fluorine (F) levels. The authors found that the dominating factor for corrosion, irrespective of the metallization scheme, is the absolute Cl level. The preferred passivation is an in situ F:Cl replacement since a polymer passivation results in higher Cl levels due to entrapment. While eater rinses and N₂ bakes help with reducing Cl levels, the effect is negligible compared to resist removal, as the majority of the Cl trapped is the resist. The effect of resist type and/or thickness on Cl levels need further investigation