Patent ID: 11929281
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method comprising:
etching a dielectric layer to form an opening, wherein a first conductive feature underlying the dielectric layer is exposed to the opening;
depositing a sacrificial spacer layer extending into the opening;
performing a first etching process to etch the sacrificial spacer layer, wherein a first bottom portion of the sacrificial spacer layer at a bottom of the opening is removed to reveal the first conductive feature, and a first vertical portion of the sacrificial spacer layer in the opening and on a sidewall of the dielectric layer is left to form a sacrificial ring;
depositing a protection layer extending into the opening and on the sacrificial ring;
performing a second etching process to etch the protection layer, wherein a second bottom portion of the protection layer is removed to reveal the first conductive feature, and a second vertical portion of the protection layer in the opening is left to form a protection ring;
forming a second conductive feature in the opening, wherein the second conductive feature is encircled by the sacrificial ring, and is over and electrically coupled to the first conductive feature; and
removing the sacrificial ring to form an air spacer.