Patent ID: 11929329
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 8:
9. A method of forming semiconductor device, comprising:
forming a low-k dielectric layer over a substrate;
forming a cap layer on the low-k dielectric layer, wherein a carbon atom content of the cap layer is greater than a carbon atom content of the low-k dielectric layer;
forming a metal-containing mask layer on the cap layer;
patterning the cap layer and the low-k dielectric layer by using the metal- containing mask layer as a mask, thereby forming an opening in the cap layer and the low-k dielectric layer; and
forming a conductive layer in the opening,
wherein the method further comprises forming a four-layer etch stop structure between the low-k dielectric layer and the substrate, wherein the opening has a lower opening and an upper opening wider than the lower opening, and the entire four-layer etch stop structure is located around a lower sidewall of the lower opening.