A contact hole burying method is provided including the steps of: coating an oxide layer on a substrate and removing the oxide layer except for a portion thereof to form a contact hole extending through the oxide layer in electrical contact with the oxide layer; sequentially forming a metal barrier layer and wet layer on the oxide layer and inside the contact hole to form an electrical connection to the substrate; forming a conductive metal layer on the wet layer; removing impurity ions and oxide material, which remain in the conductive metal layer which decrease mobility of metal atoms on a surface of said conductive layer due to absorption and oxidation, by a cleaning-etching process using a plasma; and reflowing the conductive metal layer at a relatively low temperature in a reactive furnace where the cleaning-etching process is performed to completely fill the contact hole.