Study on Chemical Activity of Electroless Copper Plating

Electroless copper plating of insulating substrates typically requires the pre-deposition of Pd/Sn catalyst layer onto the surface to initiate the chemical reactions; Accordingly, it’s high-profile process to achieve efficient Pd/Sn cluster adhesion and good copper plating performance. This paper showed copper thickness and dimple hole depth of the electroless plating were affected by chemicals following different activation times. The composition, microstructure, size and roughness evolution were characterized using Transmission Electron Microscope (TEM). The structural studies revealed that copper particle size depends not only on the size and coverage of the Pd/Sn cluster, but also on the degree of activation of the chemicals. In order to make deposition copper more compact and uniform to decrease dimple hole depth, dummy boards are generally used to enhance the potion activity before electroless copper plating. This paper will provide chemical activity and plating efficiency relationship to avoid poor activity impact plating quality and process event.