The surface morphology of a UV excimer lamp photodefimed palladium activation layer and its effect on subsequent electroless copper deposition have been studied on 96% alumina substrates using an atomic force microscope (AFM). The morphology of the activation layer and the density of the palladium catalyst are important factors affecting the initial stages of the electroless deposition and the microstructure of the copper film. Under activation conditions on which a subsequent electroless copper deposit exhibited good adhesion characteristics, the palladium activation was found to have a nodular structure with a large distribution of palladium particle sizes of the order of 10 nm at grain boundaries and the edges of grain steps, with smaller activation particles observed on smoother areas of the alumina grains. The influence of substrate morphology on the nature of the catalytic sites and thence, on the nature of the subsequently deposited metal was investigated, both at the nucleation stage, and as the autocatalytic electroless deposition reaction proceeded. The recrystallisation of the initial electroless deposit, the morphology of the resulting copper films and its relationship to catalyst particle size are reported. The principal determining factors in the substrate and activation layer morphology which control the microstructure of the electroless copper deposit are discussed.