Forming self-aligned vertical interconnect accesses (VIAs) in interconnect structures for integrated circuits (ICs)

摘要

Forming self-aligned vertical interconnect accesses (vias) in interconnect structures for integrated circuits (ICs) is disclosed. To reduce or avoid misalignment of a via to an underlying, interconnected metal line, vias are fabricated in the interconnect structure to be self-aligned with an underlying, interconnected metal line. In this regard, underlying metal lines are formed in a dielectric layer. A recess is formed in an underlying metal line below a top surface of an inter-layer dielectric. A stop layer is disposed above the inter-layer dielectric and within the recess of the underlying metal line. The stop layer allows a via tunnel to be formed (e.g., etched) down within the recess of the underlying metal line to self-align the via tunnel with the underlying metal line. A conductive material is then deposited in the via tunnel extending into the recess to form the self-aligned via interconnected to the underlying metal line.