Self-aligned contact employing a dielectric metal oxide spacer

Abstract

A dielectric liner is formed on sidewalls of a gate stack and a lower contact-level dielectric material layer is deposited on the dielectric liner and planarized. The dielectric liner is recessed relative to the top surface of the lower contact-level dielectric material layer and the top surface of the gate stack. A dielectric metal oxide layer is deposited and planarized to form a dielectric metal oxide spacer that surrounds an upper portion of the gate stack. The dielectric metal oxide layer has a top surface that is coplanar with a top surface of the planarized lower contact-level dielectric material layer. Optionally, the conductive material in the gate stack may be replaced. After deposition of at least one upper contact-level dielectric material layer, at least one via hole extending to a semiconductor substrate is formed employing the dielectric metal oxide spacer as a self-aligning structure.