On the Texture of Electroless Copper Films

Abstract

Textures of electroless copper films were investigated as a function of bath parameters and of the plating base. The top surface layer of films deposited on titanium‐seeded glass substrates is (100)‐textured when the baths contain surfactant, and (111)‐textured when they are free of surfactant. In both cases the crystals near the bottom surface are randomly oriented. Cyanide concentration and plating rate only have small effects on textures. The texture of peel‐apart copper foils, the second kind of applied plating base, is of the (110) type. Electroless films on these foils contain an increased number of (100)‐oriented grains; but (110) orientation is still dominating when surfactant‐free baths are used, whereas baths containing surfactant produce (100)‐textured deposits. The results are discussed in terms of the “survival of the slowest” rule. They suggest preferred growth of (100) faces in absence of surfactant causing dominance of (111)‐oriented crystals, and blocking of (100) faces in presence of surfactant causing dominance of (100)‐oriented crystals in the film.