Method of Forming Vertical Contacts in Integrated Circuits

摘要

A method of forming vertical contacts in an integrated circuit that couple one or more metal lines in a given metallization level to first and second features occupying different levels in the integrated circuit comprises various processing steps. A first etch stop layer is formed overlying at least of portion of the first feature while a second etch stop layer is formed overlying at least a portion of the second feature. An ILD layer is formed overlying the first and second etch stop layers. A photolithographic mask is formed overlying the ILD layer. The photolithographic mask defines a first opening over the first feature and a second opening over the second feature. A first etch process etches a first hole in the ILD layer through the first opening in the photolithographic mask that lands on the first etch stop layer and etches a second hole in the ILD layer through the second opening that lands on the second etch stop layer. Subsequently, a second etch process further etches the first hole so that it lands on the first feature.