Abstract: An electroless plating deposition speed measuring apparatus is provided with a sensor having an electrode couple whose pair of electrodes are opposed to each other and a sensor drive circuit that cyclically applies voltage to the electrode couple to measure a polarization resistance between the pair of electrodes of the electrode couple. Measuring data from the sensor drive circuit are supplied to a processing circuit. The processing circuit computes and processes the measuring data to find the plating deposition speed. Data of the plating deposition speed from the processing circuit are supplied to a display circuit to display the data of the plating deposition speed. In a preferred embodiment, each of the pair of electrodes of the electrode couple has a conductor and a non-conductor, wherein the surfaces of the conductors and the non-conductors of the respective electrodes are arranged in facing and opposite relation to each other.

Abstract: An electroless copper plating solution comprising a cupric salt, a copper complexing agent, a reducing agent, a pH adjustor, L-arginine and at least one of .alpha.,.alpha.'-dipyridyl and a cyano complex compound can give plated films high in ductility and adhesive strength and excellent in mechanical properties.