An electroplating process has been employed to grow high-quality thin films of copper on tin oxide transparent semiconductor with excellent adhesion. It is shown that electrolysis reduction as a surface modification process prior to the electrodeposition is essential for good adhesion of the resulting copper coating. Experimental results obtained for electrolysis, argon plasma cleaning, and surface roughness measurements indicate that the formation of a monolayer of low valence tin oxide may be significant to the improvements in plating process and deposit adhesion. A mechanism whereby SnO(x) formation may facilitate improved adhesion is proposed.