Method of contact hole burying

A method for completely filling a contact hole comprising the steps of:

• coating an oxide layer on a substrate and removing said oxide layer except for a portion thereof to form said contact hole extending through said oxide layer in electrical contact with said substrate;
• sequentially forming a metal barrier layer and a wet layer on said oxide layer and inside said contact hole to form an electrical connection with said substrate;
• forming a conductive metal layer on said wet layer;
• removing impurity ions and oxide material, which remain in said conductive metal layer and decrease mobility of metal atoms on a surface of said conductive metal layer due to absorption and oxidation, by a cleaning-etching process using a plasma in a reflow reaction furnace;
• and
• reflowing said conductive metal layer at a relatively low temperature between 300.degree. to 500.degree. C. in said reflow reaction furnace where the cleaning-etching process is performed in the plasma state where said surface of said conductive metal layer is cleaned and etched to completely fill said contact hole,
• wherein the surface of said conductive metal layer is cleaned and etched by maintaining said reflow reactive furnace having a plasma module at several torrs of pressure and generating a plasma.