Semiconductor device and manufacturing method thereof

Abstract

The invention provides a semiconductor device and a manufacturing method thereof. The manufacturing method of the semiconductor device comprises the steps of forming a groove filling structure in a substrate of a pixel region, and clamping a high-K dielectric layer between a side wall of a filling material in the groove filling structure and a substrate; covering a buffer dielectric layer on a surface of the substrate in the pixel region; etching the buffer dielectric layer to form a first opening which at least exposes parts of the substrate at a periphery of a top side wall of the groove filling structure and / or at least parts of a top of the groove filling structure; filling a first conductive metal layer in the first opening so as to be electrically connected with the exposed parts ofthe substrate and / or the groove filling structure; and forming a metal grid layer on the buffer dielectric layer and electrically connecting the metal grid layer with the first conductive metal layer.In the technical scheme of the invention, the metal grid layer is electrically connected with the exposed parts of the substrate and / or the groove filling structure so that electrical performance ofthe semiconductor device can be optimized and improved.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, in particular to a semiconductor device and a manufacturing method thereof. Background technique [0002] In the back-illuminated CMOS image sensor (Back-side Illumination CMOS ImaginationSensor, referred to as BSI-CIS) manufacturing process, deep trench isolation (Deep Trench Isolation, referred to as DTI) technology and back metal grid (Backside Metal Grid, referred to as BMG ) technology can make the back-illuminated CMOS image sensor have better optical performance. [0003] However, in the existing process of making a back-illuminated CMOS image sensor, there is a buffer medium layer between the metal grid in the pixel area and the underlying substrate and deep trench filling structure, so that the metal grid and the underlying There is only a physical connection between the substrate and the deep trench filling structure, but no electrical connection, which mak...

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Problems solved by technology

[0003] However, in the existing process of making a back-illuminated CMOS image sensor, there is a buffer medium layer between the metal grid in the pixel area and the underlying substrate and deep trench filling structure, so that the metal grid and the underlying There is only a physical connection between the substrate and the deep trench filling structure, but no electrical connection, which makes it impossible to optimize and improve the electrical performance of the back-illuminated CMOS image sensor

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