A two-dimensional computer simulation for electroless copper deposition was carried out using a Monte Carlo method. The equilibrium adsorption constants of ligands and Cu(II) ligand complexes on a sulssh ate were calculated for ethanolamine. The calculated equilibrium adsorption constants agreed well with the experimental results. Microvoid fractions in the plating structure were also estimated based on the equilibrium adsorption constants. The void fraction was useful in evaluating the fatigue ductility of copper plating.