Back-illuminated image sensor and forming method thereof

Abstract

A back-illuminated image sensor and a forming method thereof are provided, the forming method comprising: providing a semiconductor substrate, the semiconductor substrate including a first side and asecond side opposite to the first side, wherein a plurality of discrete photosensitive regions are formed in the semiconductor substrate on the first side, the photosensitive regions being adapted tosense light incident from the second side; Forming a first dielectric layer on a second side surface of the semiconductor substrate; Forming a transparent color filter layer correspondingly on the surface of the first dielectric layer above the partial number of photosensitive regions; Forming a light-absorbing material layer covering surfaces of the transparent color filter layer and the first dielectric layer; Etching the light-absorbing material layer without a mask to form an opaque sidewall on the sidewall surface of the transparent color filter layer; a color filter layer is formed on the surface of the first dielectric layer between the transparent filter layers. The back-illuminated image sensor formed by the method of the invention improves the performance of anti-crosstalk, and has the advantages of simple process and high integration level.

Description

technical field [0001] The invention relates to an image sensor, in particular to a back-illuminated image sensor and a forming method thereof. Background technique [0002] Semiconductor image sensors are used to sense radiation such as light. Complementary metal-oxide semiconductor (CMOS) image sensors (CIS) and charge-coupled device (CCD) sensors are widely used in still digital cameras, camera phones, digital video cameras, medical imaging devices (such as gastroscopes), and automotive imaging devices . These devices utilize an array of pixels (which may include photodiodes (photosensitive regions) and transistors) in the substrate to absorb radiation directed at the substrate and convert the sensed radiation into electrical signals. [0003] A backside illuminated (BSI) image sensing device is one type of image sensing device. Backside illuminated (BSI) image sensing devices can be used to detect light from the backside of the substrate. Compared with front-illumina...

AI Technical Summary

Problems solved by technology

However, back-illuminated (BSI) image-sensing devices produced by existing methods for manufacturing back-illuminated (BSI) image-sensing devices still have defects. For example, in order to reduce crosstalk between adjacent pixels, several After the pixels, a metal grid will be formed on the back of the semiconductor substrate; and then a color filter will be formed on the metal grid. This manufacturing process is relatively complicated, and the effect of anti-crosstalk needs to be improved.

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