Semiconductor device and manufacturing method thereof

Abstract

The invention provides a semiconductor device and a manufacturing method thereof, and the manufacturing method of the semiconductor device comprises: forming a trench filling structure in a substrateof a pixel region, and further clamping a high-K dielectric layer between the side wall of a filling material in the trench filling structure and the substrate; forming a plug structure in the substrate of the pad region; covering a buffer dielectric layer on the surface of the substrate in the pixel region and the bonding pad region; etching the buffer dielectric layer to form a first opening which at least exposes part of the substrate at the periphery of the top side wall of the trench filling structure and / or at least part of the top of the trench filling structure; and forming a metal grid layer on the buffer dielectric layer of the pixel region, and filling the first opening so as to be electrically connected with the exposed part of the substrate and / or the trench filling structure.According to the technical scheme of the invention, the metal grid layer is electrically connected with the exposed part of the substrate and / or the trench filling structure, so that the electrical performance of the 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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