International Business Machines Corporation
ETCH STOP LAYER REMOVAL FOR CAPACITANCE REDUCTION IN DAMASCENE TOP VIA INTEGRATION

Abstract:

A method of forming an interconnect structure includes forming at least one second-level interconnect in a sacrificial dielectric layer that is formed on an upper surface of a sacrificial etch stop layer, and removing the sacrificial dielectric layer and the sacrificial etch stop layer while maintaining the at least one second-level interconnect so as to expose an underlying dielectric layer. The method further includes depositing a replacement dielectric layer on an upper surface of the underlying dielectric layer to embed the at least one second-level interconnect in the replacement dielectric layer. Accordingly, an interconnect structure can be formed that includes one or more first-level interconnect in a dielectric layer and one or more second-level interconnects in a replacement dielectric layer stacked on the dielectric layer. The replacement dielectric layer directly contacts the dielectric layer.