A method of filling a conductive material in a three dimensional integration feature formed on a surface of a wafer is disclosed. The feature is optionally lined with dielectric and/or adhesion/barrier layers and then filled with a liquid mixture containing conductive precursor, such as a solution with dissolved ruthenium precursor or a dispersion or suspension with conductive particles (e.g., gold, silver, copper), and the substrate is rotated while the mixture is on its surface. Then, the liquid carrier is dried from the feature, leaving a conductive layer in the feature. These two steps are optionally repeated until the feature is filled up with the conductor. Then, the conductor is annealed in the feature, thereby forming a dense conductive plug in the feature.