Patent ID: 11955496
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An image sensor, comprising:
an image sensing die having a front-side and a back-side opposite to the front-side;
a plurality of pixel regions disposed within the image sensing die and respectively comprising a photodiode configured to convert radiation that enters from the back-side of the image sensor die into an electrical signal, the photodiode comprising a photodiode doping column with a first doping type surrounded by a photodiode doping layer with a second doping type that is different than the first doping type; and
a back-side deep trench isolation (BDTI) structure disposed between adjacent pixel regions and extending from the back-side of the image sensor die to a position within the photodiode doping layer;
wherein the BDTI structure comprises a doped liner with the second doping type and a dielectric fill layer, the doped liner lining a sidewall surface of the dielectric fill layer,
wherein the doped liner is formed by performing a doping process with a protective layer lining a deep trench followed by removing the protective layer prior to forming the dielectric fill layer, resulting in improved conformity from top to bottom of the doped liner.