Patent ID: 11894404
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 16:
17. A method for fabricating an optical structure, comprising:
forming a light detection region in a substrate;
forming an isolation structure surrounding the light detection region; and
forming a primary grid over the isolation structure, comprising:
forming a metal layer over the isolation structure;
forming a first dielectric layer over the metal layer;
forming an antireflective coating (ARC) layer over the first dielectric layer; and
patterning the metal layer, the first dielectric layer, and the ARC layer;

forming a second dielectric layer over the substrate, wherein a top surface of the ARC layer is below a top surface of the second dielectric layer; and
forming a secondary grid at least partially surrounded by the primary grid laterally, comprising:
forming a trench in the second dielectric layer;
forming a filling material in the trench; and
partially removing the second dielectric layer by patterning, thereby at least a portion of the filling material and a portion of the second dielectric layer below the filling material is remained.