Patent ID: 11961866
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of forming an image sensor, the method comprising:
forming a photodiode within a semiconductor substrate;
disposing an interconnect structure over the semiconductor substrate, wherein the interconnect structure comprises:
a contact etch stop layer (CESL) over the photodiode; and
a plurality of dielectric layers over the CESL, wherein at least one dielectric layer of the plurality of dielectric layers comprises a low dielectric constant (low-k) material;

patterning at least the plurality of dielectric layers, wherein patterning at least the plurality of dielectric layers comprises defining an opening above an active region of the photodiode;
depositing a cap layer on sidewalls of the opening, wherein the cap layer comprises a dielectric material having a higher moisture resistance than the low-k dielectric material; and
forming a gate stack comprising a gate dielectric and a gate electrode over the photodiode, wherein patterning the at least the plurality of dielectric layers comprises patterning the plurality of dielectric layers, the CESL and the gate electrode to define an opening in the plurality of dielectric layers, the CESL and the gate electrode, the opening exposing a portion of the gate dielectric above the active region of the photodiode.