Method of fabricating trench isolation of semiconductor device

A method of fabricating a trench isolation structure of a semiconductor device, comprising:

• providing a substrate with a trench formed therein;
• forming an oxide film on side wall and bottom surfaces of the trench;
• forming a nitride liner on the oxide film on the side wall and bottom surfaces of the trench, and on top surfaces of the substrate;
• loading the substrate into a high-density plasma (HDP) chemical vapor deposition apparatus;
• primarily heating the substrate;
• applying a first bias power to the apparatus so as to form an HDP oxide liner on an entire surface of the nitride liner, a gap remaining in the trench following formation of the HDP oxide liner;
• removing the application of the first bias power and secondarily heating the substrate;
• applying a second bias power at a power level that is greater than that of the first bias power to the substrate so as to form an HDP oxide film to fill the gap in the trench;
• and
• unloading the substrate from the apparatus.