Abstract
The miniscale throwing power of Cu (II) -EDTA complex plating baths containing potassium chloride, glycine and formaldehyde as additives, and the mechanical properties of the films obtained were investigated. The films obtained were shown to have nearly the same elongation and ultimate tensile strength as commercial high ductile electrolytic copper foil after heat-treatment for 1h at 160°C. The bath was shown to have an exellent miniscale throwing power for the production of PWB with minute holes. The miniscale throwing power is dominated with κ (∂η/∂i) s/ (l2/2d), where κ is the conductivity of electrolyte, (∂η/∂i) s is the polarization resistance at the board surface, l is the board thickness and d is the diameter of through-hole. Since the ∂η/∂i of above bath is high, good miniscale throwing index Tx (the ratio of thickness at the center of through-hole to that on the board surface), for example Tx=0.7 for PWB with l=2mm, d=0.l4mm at the current density of 2A/dm2, may be predicted.
