METHOD OF FORMING A CAPACITOR OF SEMICONDUCTOR DEVICE

摘要

A method for forming a capacitor of a semiconductor device is provided to avoid a 2-bit defect and a defect caused by the deterioration of a dielectric layer by expanding a bottom width of a capacitor. A buffer oxide layer, an etch stop layer and a mold layer(120) are sequentially formed on a substrate having a conductive pattern. The mold layer, the etch stop layer and the buffer oxide layer are anisotropically etched to form a preliminary opening exposing the conductive pattern. The etch stop layer and the buffer oxide layer that are exposed through the sidewall of the preliminary opening are partially removed to form an opening in which an upper width is not extended from the preliminary opening and a lower width is extended. A lower electrode is formed along the inner surface and bottom surface of the opening. A dielectric layer and an upper electrode are formed on the surface of the lower electrode. In forming the opening, the extension width of an opening confined by the etch stop layer is greater than that of an opening confined by the buffer oxide layer.