Patent ID: 11955430
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 13:
14. A method of manufacturing a semiconductor device, comprising:
forming a first dielectric layer over a substrate;
forming a cobalt plug in the first dielectric layer;
forming a nitride based etch stop layer on the first dielectric layer and the cobalt plug;
forming a second dielectric layer over the nitride based etch stop layer;
forming an opening in the second dielectric layer and the nitride based etch stop layer to expose an upper surface of the cobalt plug;
performing an etching operation using a fluoride containing gas to remove portions of the cobalt plug to extend the opening into the cobalt plug a desired distance from a bottom surface of the nitride based etch stop layer;
forming a recess in the cobalt plug at a bottom of the opening, wherein, in a cross-sectional view, the recess has a width that is at least greater than a width of a section of the opening located in the cobalt plug; and
forming a tungsten plug that is located in the recess, the opening, and on an upper surface of the second dielectric layer.