A cmos image sensor and its manufacturing method

Abstract

The invention provides a CMOS-type image sensor and a manufacturing method therefor. The CMOS-type image sensor comprises a second oxidation layer and a substrate located at one side of the oxidationlayer. A first trench which is recessed downwards to the second oxidation layer is formed at one side of the substrate. The substrate and the first trench are sequentially provided with an HIK layer and a first oxidation layer from the top to the bottom. A wiring groove which passes through the first oxidation layer, a high dielectric film layer and a part of the second oxidation layer is formed on the first trench which is provided with the high dielectric film layer and the first oxidation layer. The first oxidation layer and the interior of the wiring groove are provided with first metal layers. The first metal layer on of the wiring groove is provided with an aluminum wiring board, and the aluminum wiring board is electrically connected with the high dielectric film layer which is exposed by the side wall of the wiring groove through the first metal layer in the wiring groove, so as to provide a voltage for the high dielectric film layer when a voltage is applied to the aluminum wiring board, to generate a bigger potential difference between the high dielectric film layer and the substrate, to enable the substrate to have the stronger capability of electron constraint, and to reduce the white points and dark currents.

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] With the increasing demand for small size and high pixels of the camera, the requirements for the optical performance of the sensor are correspondingly more stringent. The traditional process uses the HiK process to bind the electrons on the silicon surface to the surface and block the injection of external electrons to provide the optical properties of the product (White pixel, Dark current, etc.) The method can no longer meet the needs of high-end customers. figure 1 Shown is a conventional CMOS type image sensor. [0003] The traditional method adds a high dielectric film layer (HiK layer) in order to improve the optical performance of the sensor. [0004] In order to improve the optical performance and electrical performance of the CMOS image sensor, a deep trench isolation (DTI) pr...

AI Technical Summary

Problems solved by technology

However, due to the limitations of the HiK material itself, this internal potential difference is limited, and the ability to bind electrons is also limited.

Can not meet the demand for higher optical performance

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