抄録
The polarization bahavior of an electroless copper plating solution and the composition, surface appearance and cross section of the deposits have been investigated using EDTA as a complexing agent, and HCHO as a reducing agent The additives used were 2, 2'-dipyridyl (dpy), 4, 4'-dimethyl-2, 2'-dipyridyl (4, 4'-dmdpy) and 6, 6'-dimethyl-2, 2'-dipyridyl (6, 6'-dmdpy) At 70°C, the polarization behavior of baths containing dpy and 4, 4'-dmdpy was in accordance with the mixed potential theory, and copper complex ion was directly reduced to copper As a result, electron diffraction of the deposits revealed Cu alone This is explained by the supposition that dpy and 4, 4'-dmdpy, having a ferroine functional group, are preferentially adsorbed on the working electrode, preventing the alcoholate ion from being adsorbed and causing the characteristic wave of the total polarization curve to disappear Polarization curves obtained from baths containing 6, 6'-dmdpy did not show additivity at 70°C, probably because 6, 6'-dmdpy with a cuproine functional group cannot satisfactorily prevent the adsorption of the alcoholate ion on the working electorode, so that copper complex ion was reduced by two-step reaction and codeposition of Cu2O occured. Grains in the deposits from baths containing dpy and 4, 4'-dmdpy were linked together, while those from baths containing 6, 6'-dmdpy remained comparatively isolated
