Backside illuminated complementary metal-oxide-semiconductor transistor (CMOS) imaging sensor and preparation method thereof

Abstract

The invention discloses a backside illuminated complementary metal-oxide-semiconductor transistor (CMOS) imaging sensor which comprises a semiconductor substrate. The semiconductor substrate comprises at least two pixel unit areas. The semiconductor substrate is provided with a front face and a back face which is opposite to the front face, at least two pixels are formed on the front face of the semiconductor substrate, and one pixel is arranged inside each pixel unit area. Grooves are formed in the back face of the semiconductor substrate, and the grooves are placed between every two adjacent pixel unit areas. An insulating layer is formed on the back face of the semiconductor substrate, and air gaps are formed by the insulating layer and the grooves. An optical filter and a micro lens are sequentially formed on the insulating layer. Meanwhile, the invention further provides a preparation method of the backside illuminated CMOS imaging sensor. The backside illuminated CMOS imaging sensor is adopted, light rays can be reduced or can be prevented from entering into the adjacent pixel unit areas, the phenomenon of optical crosstalk to the adjacent pixel unit areas can be avoided, and the fineness quality of the backside illuminated CMOS imaging sensor is improved.

Description

technical field [0001] The invention relates to the field of image sensors, in particular to a back-illuminated CMOS image sensor and a preparation method thereof. Background technique [0002] The image sensor is developed on the basis of photoelectric technology. The so-called image sensor is a sensor that can sense optical image information and convert it into an output signal. Image sensors can improve the visual range of the human eye, enabling people to see the microcosm and macrocosm that cannot be seen by the naked eye, see what happens in places that people cannot reach temporarily, and see various physical and chemical changes beyond the visual range of the naked eye. Life, physiology, the occurrence and development of disease, and so on. It can be seen that image sensors play a very important role in people's culture, sports, production, life and scientific research. It can be said that modern human activities can no longer be separated from image sensors. [0...

AI Technical Summary

Problems solved by technology

[0005] However, in the prior art back-illuminated CMOS image sensor, light will enter the adjacent pixel unit area, thereby causing optical crosstalk to the adjacent pixel unit area, causing the display of the back-illuminated CMOS image sensor to fade

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