Characterization of PdCl2/SnCl2 metallization catalysts on a polyetherimide surface by XPS and RBS

Abstract
A metallization catalyst (based on the PdCl2/SnCl2 system) adsorbed on polyetherimide surfaces was characterized by x‐ray photo‐electron spectroscopy (XPS), Rutherford back scattering (RBS) and transmission electron microscopy (TEM). The overall Pd/Sn ratio increased from 0.2 to 3.8 when the initial sensitized surface was treated with the accelerator solution. XPS results indicated that before acceleration, only Sn(IV) (stannic hydroxide) is obserable, and after acceleration both metallic Sn and Sn(IV) are present; palladium is present primarily in a metallic form both before and after the accelerator step. Total Pd and Sn coverages were also obtained by RBS, and the total Pd/Sn ratios agree with the XPS surface measurements for specimens just prior to metallization. TEM micrographs showed the adsorbed catalyst consisted of particles 10–50 Å in size covering only a fraction of the surface.