Method for improving white pixel of backside illuminated CMOS image sensor

Abstract

The invention discloses a method for improving a white pixel of a backside illuminated CMOS image sensor. The method for improving the white pixel of the backside illuminated CMOS image sensor comprises the steps of S1, providing a silicon-based substrate with a pixel structure; S2, depositing a silicon nitride interlayer dielectric layer on the surface of the pixel structure, wherein the adopted hydrogen ion concentration is first hydrogen ion concentration, and hydrogen ions forming the first hydrogen ion concentration are provided through a first hydrogen ion source; S3, providing a second hydrogen ion source with a second hydrogen ion concentration, and enabling hydrogen ions generated by the second hydrogen ion source to be bonded with the silicon dangling bond of the silicon nitride interlayer dielectric layer; and S4, obtaining the backside illuminated CMOS image sensor after bonding of silicon dangling bonds and the hydrogen ions. By providing the second hydrogen ion source with the second hydrogen ion concentration, the hydrogen ions are bonded with silicon dangling bonds, so that the silicon dangling bonds are greatly reduced, the image quality under dark light is improved, and the formation of white-point pixels is inhibited.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for improving white pixels of a back-illuminated CMOS image sensor. Background technique [0002] CMOS image sensors have become mainstream products in the image sensor market due to their low power consumption, low cost, small size, random readability, and high integration. Backside Illuminated CMOS Image Sensor (BSI CIS) is an improved pixel structure based on the traditional Frontside Illuminated CMOS Image Sensor under the condition of shrinking pixel size. The advantage is that the metal wiring and interlayer dielectric layer between the filter and the photodiode area are moved to the other side of the chip, so that light can enter the photodiode area from the "back side", thereby significantly improving the quantum effect. [0003] For back-illuminated CMOS image sensors, as is well known, in general, the fewer silicon dangling bonds the better...

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Problems solved by technology

[0006] The present invention is aimed at conventional back-illuminated CMOS image sensors, which generally have a large number of silicon dangling bonds, and the silicon dangling bonds, as an effective trap center, can acquire electrons or holes, thereby resulting in white pixels. Defects that have a great impact on the imaging quality of the device provide a method to improve the white pixels of the back-illuminated CMOS image sensor

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