ON THE ACTION OF MAGNETIC GRADIENT FORCES IN MICRO-STRUCTURED COPPER DEPOSITION.

Abstract

International audienceThe relative influence of the Lorentz force and magnetic gradient force on micro-structured copper deposition is studied with simple magnetic elements consisting of cylindrical permanent magnets placed closely behind the surface of the cathode. Analytical findings and numerical simulations reveal that for magnets of small diameter the magnetic gradient force dominates. In experiments, it is found that the thickness of the deposited copper layer increases in the vicinity of the magnets. The combined analysis of simulations and experiments shows that this enhancement of mass transfer results from a local convection towards the electrode, which is forced by the magnetic gradient force. Finally, a more general case with electrically inert paramagnetic ions is discussed, where an inverse structuring effect can be expecte