METHOD OF FORMING STI-TYPE ELEMENT ISOLATING FILM IN SEMICONDUCTOR DEVICE

摘要

PURPOSE: An STI-type element isolating film forming method is provided to remove voids produced at pad oxidation layer edge portions in gap-fill oxidation film deposition by reducing a thickness of a pad oxidation layer and increasing a thickness of a sidewall oxidation layer. CONSTITUTION: A pad oxidation layer(102) is layered on a semiconductor substrate(100) with a thickness of 30 to 70 angstrom. A nitride film(104) is layered on the pad oxidation layer(102) with a thickness of 500 to 2000 angstrom. A photoengraving and an etching are carried out by using an element isolating mask to pattern the nitride film(104) and the pad oxidation layer(102). A trench is formed in the substrate exposed by the pattern. A sacrificial oxidation layer is formed through oxidation to compensate etching loss in the trench. The sacrificial oxidation layer is removed. A sidewall oxidation layer(110) is formed with a thickness of 200 to 300 angstrom to remove a groove portion of the pad oxidation film(102) due to etching loss while smoothing corner upper faces of the trench. A gap-fill oxidation layer is filled into the trench and flattened. The nitride film(104) is removed to form an element isolating film on the substrate.