Patent ID: 11862650
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 3:
4. An image sensor, comprising:
a photodetector disposed in a semiconductor substrate;
a light filter grid structure disposed over a first side of the semiconductor substrate;
a light filter disposed in the light filter grid structure;
a dielectric layer disposed over the first side of the semiconductor substrate and between the photodetector and the light filter;
a metal grid disposed in the dielectric layer, wherein the metal grid comprises a first portion disposed on a first side of the photodetector and a second portion disposed on a second side of the photodetector opposite the first side of the photodetector; and
a noise reducing structure disposed vertically between the light filter and the first side of the semiconductor substrate and laterally between the first portion of the metal grid and the second portion of the metal grid, wherein the noise reducing structure has a first refractive index that is higher than a second refractive index of the dielectric layer, and wherein the light filter grid structure has a third refractive index that is less than a fourth refractive index of the light filter, wherein the fourth refractive index squared minus the third refractive index squared is less than about 0.25.