Image sensor and formation method thereof

Abstract

The technical scheme discloses an image sensor and a formation method thereof; the image sensor forming method comprises the following steps: providing a semiconductor substrate; forming a discrete photodiode and a deep trench isolation structure in the semiconductor substrate, wherein the deep trench isolation structure is located between the photodiode; forming an interlayer dielectric layer onthe surface of the semiconductor substrate so as to cover the photodiode and the deep trench isolation structure; forming an amorphous form carbon layer on the interlayer dielectric layer; etching theamorphous form carbon layer so as to expose the interlayer dielectric layer surface, thus forming a groove; forming an insulation layer on the surface of the amorphous form carbon layer, and the sidewalls and the bottom of the groove; forming a metal layer on the surface of the insulation layer; etching the metal layer and the insulation layer so as to expose the interlayer dielectric layer surface, thus forming discrete metal grids; removing the amorphous form carbon layer. When the key dimensions of the formed metal grids are small enough, collapse conditions cannot happen.

Description

technical field [0001] The invention relates to the manufacturing field of semiconductor devices, in particular to an image sensor and its forming method, especially a back-illuminated image sensor and its forming method. Background technique [0002] An image sensor receives light signals from an object and converts the light signals into electrical signals, which can then be transmitted for further processing, such as digitization, and then stored in a storage device such as a memory, optical or magnetic disk, or used in a display display, print, etc. Image sensors are commonly used in devices such as digital cameras, video cameras, scanners, facsimile machines, and the like. [0003] Image sensors are generally of two types, Charge Coupled Device (CCD) sensors and CMOS Image Sensors (CIS). CCD is called a photocoupler device, which collects charge through the photoelectric effect, and the charge of each row of pixels is sent to the analog shift register with the clock s...

AI Technical Summary

Problems solved by technology

[0005] However, with the continuous reduction of process nodes, the size of the metal grid is becoming more and more difficult to control in the process of manufacturing back-illuminated image sensors.

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