Patent ID: 6967156
Filing Date: 2005-11-22
Classification: H01L

Abstract:
1. A method of forming an aligned dual damascene opening, comprising the sequential steps of: providing a structure having a metal structure formed thereover; forming a layer stack over the metal structure; the layer stack comprising, in ascending order: a bottom etch stop layer; a lower dielectric material layer; a middle etch stop layer; a middle dielectric material layer; and an upper dielectric layer; wherein: patterning the upper dielectric layer to form an opening exposing a portion of the underlying middle dielectric material layer; the opening having a width; forming a patterned mask layer over the patterned upper dielectric layer leaving exposed opposing portions of the patterned upper dielectric layer; patterning the middle dielectric material layer to form an opening therein using the patterned mask layer and the exposed portions of the upper dielectric layer as masks; the middle dielectric material layer opening exposing a portion of the middle etch stop layer; removing the middle etch stop layer at its exposed portion to form a patterned middle etch stop layer having an opening exposing a portion of the lower dielectric material layer; simultaneously patterning: removing the patterned mask layer; and removing the patterned upper dielectric material layer, the exposed portions of the patterned middle etch stop layer and the exposed portion of the bottom etch stop layer to convert: to form the aligned dual damascene opening.