Palladium activation on TaNx barrier films for autocatalytic electroless copper deposition

Palladium activation on dc magnetron sputtered tantalum and tantalum nitrides (TaN(x)) for autocatalytic electroless copper deposition has been investigated with various nitrogen content by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM), plan view transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The addition of a small amount of nitrogen induced a phase transformation of as-deposited TaN(x) films. As the nitrogen flow rate was increased, the electrical resistivity of the as-deposited TaN(x) films initially decreased for nitrogen flow rate up to 10 standard cubic centimeters per minute (sccm) followed by an increase for a nitrogen flow rate above about 20 sccm. FE-SEM and plan view TEM analyses showed that the density of palladium nuclei increased with nitrogen content. In contrast, the grain size of TaN(x) films decreased with increasing nitrogen flow rate. XPS results of palladium-activated TaN(x) films showed that no chemical shift of metallic palladium peak was observed after the activation process. (C) 2001 The Electrochemical Society.