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

Claim 0:
1. A semiconductor device comprising:
a fin protruding above a substrate;
a gate structure over the fin;
source/drain regions on opposing sides of the gate structure;
one or more dielectric layers over the source/drain regions;
a contact plug extending through the one or more dielectric layers and electrically coupled to an underlying electrically conductive feature, wherein an upper surface of the one or more dielectric layers distal from the substrate is level with an upper surface of the contact plug, wherein an upper portion of the contact plug has a linear sidewall profile, and a lower portion of the contact plug has a curved sidewall profile, wherein the contact plug comprises:
an electrically conductive material;
a spacer layer around the electrically conductive material; and
an air gap between the spacer layer and the one or more dielectric layers, wherein the one or more dielectric layers have a protrusion portion that protrudes into the air gap and seals the air gap; and

a second dielectric layer over the contact plug and the one or more dielectric layers, wherein the protrusion portion separates the air gap into a lower air gap and an upper air gap, wherein the lower air gap is between the protrusion portion and the underlying electrically conductive feature, and the upper air gap is between the protrusion portion and the second dielectric layer.