Method of forming shallow trench isolation

摘要

A method of forming a shallow trench isolation structure. A pad oxide layer and a mask layer are sequentially formed over a substrate. A portion of the pad oxide layer, mask layer and substrate are removed to form a trench in the substrate. A first stage high-density plasma chemical vapor deposition having a high etching/deposition ratio is conducted to form a layer of insulation material over the substrate. A second stage high-density plasma chemical vapor deposition having a lower etching/deposition rate is conducted to form a second layer of insulation material over the substrate and completely fills the trench. Insulating material outside the trench region is removed. Finally, the mask layer and the pad oxide layer are sequentially removed to form a complete STI structure.