Method of forming shallow trench isolation structure by isotropically etching a pad nitride layer with exposed top structure

摘要

An isolation structure is provided by a method which includes forming a pad oxide layer on a semiconductor substrate and then forming a pad nitride layer on the pad oxide layer. An opening is then formed which extends through the pad nitride layer, the pad oxide layer, and into the semiconductor substrate. The pad nitride layer is then isotropically etched, thereby pulling-back the pad nitride layer from the portion of the opening extending through the pad oxide layer. An insulating layer is formed to fill in the opening including the portion of the opening formed by the pulling-back of the pad nitride layer. The deposited insulating layer is then planarized using the pulled-back nitride layer as a stopper layer. The pulled-back pad nitride layer and the pad oxide layer are then removed.