A method of filling a conductive material in a three dimensional integration structure feature formed on a surface of a wafer is disclosed. The feature is filled with a dispersion containing a plurality of conductive particles and a solvent. Then, the solvent is removed from the feature, leaving the plurality of conductive particles in the feature. These two steps are repeated until the feature is filled up with the conductive particles. Then, the conductive particles are annealed in the feature, thereby forming a dense conductive plug in the feature.