Method for shallow trench isolation fabrication and partial oxide layer removal

摘要

A method for forming thoroughly deposited shallow trench isolation. A first oxide layer is formed conformally over the surface of a semiconductor substrate and on a trench thereon with an aspect ratio greater than 3. A liquid etching shield is filled in the trench by spin-spraying to cover the oxide layer in the trench. An etchant is then sprayed over the surface of the semiconductor substrate to remove the uncovered oxide layer and expose the surface of the semiconductor substrate. The density of the etchant is less than that of the liquid etching shield. A second oxide layer is deposited in the trench to form isolation without voids or seams.