COMS (complementary metal-oxide semiconductor) image sensor and manufacturing method thereof

Abstract

The invention provides a COMS (complementary metal-oxide semiconductor) image sensor and a manufacturing method thereof. The manufacturing method comprises the following steps: forming a first doped area on the surface of a semiconductor substrate; sequentially forming a gate oxidation layer and gate polycrystalline silicon; forming a second doped area in the semiconductor substrate; depositing a dielectric layer and forming a side wall through an exposure and etching process; forming a third doped area on the surface of the semiconductor substrate; removing the dielectric layer on the surface of the semiconductor substrate; and forming a fourth doped area in the first doped area. According to the manufacturing method provided by the invention, the gate side wall is formed by etching, ion injection is performed after removal of a photoresist to form the third doped area on the surface of the semiconductor substrate, and then the dielectric layer on the surface of the semiconductor substrate is removed to prevent secondary ion injection from damaging the semiconductor substrate on the surface of a light-sensitive diode, so that white points of the CMOS image sensor caused by damage of a semiconductor are avoided, and the quality of the CMOS image sensor is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a CMOS image sensor and a manufacturing method thereof. Background technique [0002] Image sensors are an important part of digital cameras. According to the different components, it can be divided into two categories: CCD (Charge Coupled Device, charge-coupled device) and CMOS (Complementary Metal-Oxide Semiconductor, metal oxide semiconductor device). With the continuous development of the manufacturing process of CMOS integrated circuits, especially the design and manufacturing process of CMOS image sensors, CMOS image sensors have gradually replaced CCD image sensors and become the mainstream. Compared with CMOS image sensors, it has the advantages of higher industrial integration and lower power. [0003] In a CMOS image sensor, a transfer transistor (TX) is used to transfer photogenerated electrons in a photodiode. [0004] figure 1 A schematic structural diagra...

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Problems solved by technology

[0008] The invention provides a COMS image sensor and a manufacturing method thereof to solve the problem of white spots in the COMS image sensor caused by damage to the surface of the semiconductor substrate in the prior art

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