Feature-scale simulation of resist-patterned electrodeposition

• Published in: IBM journal of research and development 1993-03, Vol.37 (2), p.125-142
• Main Author: Dukovic, J. O.
• Format: Article
• Language: English
• ISSN: 0018-8646; 0018-8646
• DOI: 10.1147/rd.372.0125

A numerical simulation of resist-patterned or "through-mask" electroplating has been performed to investigate shape evolution at the scale of small lithographic features. Shape evolution and step coverage have a significant influence on the shapes of such microelectronic structures as conductor lines, vias, and magnetic pole pieces. The simulation and associated analysis are based on a model for the rate distribution of the electrodeposition reaction that includes the depletion of the depositing metal ions and the inhibiting action of leveling agents. A stagnant boundary layer is assumed to be present, and the diffusion theory of leveling with a one-parameter description of kinetic inhibition is employed. The results show that when the geometry of a feature cavity makes possible the occurrence of concentration-field effects (such as radial diffusion), an uneven metal-ion flux should cause nonuniform growth at high fractions of the limiting current, and leveling agents should exert an opposing effect, even causing a strong reverse nonuniformity in some cases.