Middle-Of-Line Interconnect Structure Having Air Gap And Method Of Fabrication Thereof

• Main Authors: Su, Yi-Nien, Shieh, Jyu-Horng
• Format: Patent
• Language: English
• Published: 01.12.2022
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

Middle-of-line (MOL) interconnects that facilitate reduced capacitance and/or resistance and corresponding techniques for forming the MOL interconnects are disclosed herein. An exemplary MOL interconnect structure includes a device-level contact disposed in a first insulator layer and a ruthenium structure disposed in a second insulator layer disposed over the first insulator layer. The device-level contact physically contacts an integrated circuit feature, and the ruthenium structure physically contacts the device-level contact. An air gap separates sidewalls of the ruthenium structure from the second insulator layer. A top surface of the ruthenium structure is lower than a top surface of the second insulator layer. A via disposed in a third insulator layer extends below the top surface of the second insulator layer to physically contact the ruthenium structure. A remainder of a dummy contact spacer layer may separate the first insulator layer and the second insulator layer.