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 includes: forming a trench filling structure in the substrate of the pixel region, and the sidewall of the filling material in the trench filling structure and the substrate A high-K dielectric layer is interposed therebetween; the buffer dielectric layer is covered on the substrate surface of the pixel region; the buffer dielectric layer is etched to form at least part of the substrate and / or the periphery of the top sidewall of the trench filling structure exposed A first opening at least part of the top of the trench filling structure; filling the first conductive metal layer in the first opening to electrically connect with the exposed part of the substrate and / or the trench filling structure; forming a metal grid layer on the on the buffer medium layer and electrically connected with the first conductive metal layer. The technical solution of the present invention enables the metal grid layer to be electrically connected to the exposed part of the substrate and / or the trench filling structure, thereby enabling the optimization and improvement of the electrical performance of the semiconductor device.

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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