US 12,451,391 B2
Image sensor with dual trench isolation structure
Cheng-Hsien Chou, Tainan (TW); Sheng-Chau Chen, Tainan (TW); Tzu-Jui Wang, Fengshan (TW); and Sheng-Chan Li, Tainan (TW)
Assigned to Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsin-Chu (TW)
Filed on May 19, 2023, as Appl. No. 18/320,523.
Application 18/320,523 is a division of application No. 17/197,330, filed on Mar. 10, 2021, granted, now 11,705,360.
Prior Publication US 2023/0290672 A1, Sep. 14, 2023
Int. Cl. H01L 21/762 (2006.01); H10F 39/00 (2025.01); H10F 39/12 (2025.01); H10F 39/18 (2025.01)
CPC H01L 21/76224 (2013.01) [H10F 39/024 (2025.01); H10F 39/18 (2025.01); H10F 39/199 (2025.01); H10F 39/807 (2025.01)] 20 Claims
OG exemplary drawing
 
1. An image sensor comprising:
a substrate;
a photodetector in the substrate, the photodetector comprising a semiconductor guard ring along a first side of the substrate;
a shallow trench isolation (STI) structure extending into the substrate from the first side of the substrate;
an outer isolation structure extending into the substrate from a second side of the substrate, opposite the first side of the substrate, to the STI structure, wherein the STI structure and the outer isolation structure laterally surround the photodetector; and
an inner isolation structure over the photodetector and extending into the substrate from the second side of the substrate, wherein the inner isolation structure is vertically separated from the photodetector by the substrate and has a ring-shaped top layout, and wherein the outer isolation structure laterally surrounds the inner isolation structure.