THE MORPHOLOGY OF ELECTROLESS NI DEPOSITION ON A COLLOIDAL PD(II) CATALYST

The surface morphology of a surface-bound colloidal Pd(II) catalyst an d its effect on the particle size of an electroless Ni deposit is exam ined. The deposited catalyst is found to have a broad distribution of particle sizes with the largest particles reaching approximately 50 nm in diameter. Catalyst surface coverages as low as 20% are found to be sufficient to initiate complete and homogenous metallization. The dis tribution of particle sizes for the electroless metal deposit, found t o be a function of plating time, is broad with the maximum Ni particle size exceeding 120 nm. Results indicate controlling the size of the b ound catalyst is the principal determining factor in controlling the p article size of the electroless deposit. Modification of the surface b y depleting the concentration of surface functional groups capable of binding catalyst is used to shift the size distribution of bound catal yst to smaller values. A resulting three- to fourfold reduction in the particle size of the electroless deposit is demonstrated.