Patent ID: 11916147
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 17:
18. A semiconductor device comprising:
a substrate;
a transistor over the substrate, wherein the transistor comprises a gate structure and source/drain regions on opposing sides of the gate structure;
a first dielectric layer over the substrate;
a conductive plug extending through the first dielectric layer and electrically coupled to a conductive feature of the transistor, wherein an upper portion of the conductive plug has linear sidewalls, and a lower portion of the conductive plug has curved sidewalls;
a spacer layer around the conductive plug;
an air gap between the spacer layer and the first dielectric layer, wherein the first dielectric layer has a protrusion portion proximate to an upper surface of the first dielectric layer, wherein the protrusion portion extends into the air gap;
a second dielectric layer over the first dielectric layer and the conductive plug; and
a conductive line in the second dielectric layer and over the air gap, wherein the conductive line seals the air gap, wherein a portion of the air gap is disposed between the conductive line and the protrusion portion.