Method for manufacturing CMOS image sensor

Abstract

The invention relates to a method for manufacturing a complementary metal oxide semiconductor (CMOS) image sensor. The CMOS image sensor comprises a CMOS transistor. A method for forming the gap wall of the CMOS transistor comprises the following steps of: forming a gap wall dielectric layer on a semiconductor substrate and a gate electrode, and forming a photoresist layer on the gap wall dielectric layer; imaging the photoresist layer, and retaining a photodiode area and the photoresist layer on the gap wall dielectric layer in a light doping area on one side, which is adjacent to the photodiode area, of a metal oxide semiconductor (MOS) transistor adjacent to the photodiode area; and etching the gap wall dielectric layer by taking the photoresist layer as a mask to form the gap wall of the MOS transistor, wherein the MOS transistor adjacent to the photodiode area forms the gap wall only on one side of the gate electrode which is away from the photodiode area, and the gap wall dielectric layer retained in the photodiode area is used as a substrate protective layer of the semiconductor substrate in the photodiode area simultaneously.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, and more specifically, the present invention relates to a method for manufacturing a CMOS image sensor. Background technique [0002] An image sensor is a semiconductor device that converts light signals into electrical signals. Image sensors are generally classified into two categories: Charge Coupled Devices (Charger Coupled Device, CCD) and Complementary Metal Oxide Semiconductor (CMOS) image sensors. CCD image sensor has the advantages of low read noise, large dynamic range, and high response sensitivity. However, CCD image sensor has high power consumption and complicated manufacturing process, making it difficult to realize single-chip integration with peripheral circuits. [0003] The CMOS image sensor adopts the same CMOS technology as the signal processing circuit, and the CMOS image sensor and the signal processing circuit outside the sensor can be integrated on the same...

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Problems solved by technology

[0008] However, during the etching process of the spacer, the problem that the substrate of the CMOS transistor region is etched often occurs, and the substrate damage of the CMOS transistor region will increase the leakage current of the MOS transistor, so that the MOS transistor cannot Normal work, CMOS image sensor performance degradation

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