Image sensor and forming method thereof

Abstract

The invention discloses an image sensor and a forming method thereof. The image sensor comprises a semiconductor substrate, a light sensing structure, a blocking layer and a light filtering layer, wherein the semiconductor substrate comprises a plurality of pixel areas and isolation areas located between the adjacent pixel areas; the semiconductor substrate is provided with a first surface and a second surface which are opposite to each other; the light sensing structure is located in the pixel areas of the semiconductor substrate, and the first surface of the semiconductor substrate exposes the light sensing structure; the blocking layer is located on the surface of the second surface of the semiconductor substrate, and a first groove is formed in the blocking layer, and the bottom of thefirst groove exposes the surface of the blocking layer located in the pixel areas, wherein the blocking layer is made of a pressure-resistant material; and the light filtering layer is located in thefirst groove, wherein the thermal expansion coefficient of the blocking layer material is less than that of the light filtering layer material. The performance of the image sensor is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to an image sensor and a forming method thereof. Background technique [0002] An image sensor is a semiconductor device that converts light signals into electrical signals. Image sensors are classified into complementary metal oxide (CMOS) image sensors and charge coupled device (CCD) image sensors. CMOS image sensor has the advantages of simple process, easy integration of other devices, small size, light weight, low power consumption and low cost. Therefore, with the development of image sensing technology, CMOS image sensors are increasingly used in various electronic products instead of CCD image sensors. At present, CMOS image sensors have been widely used in still digital cameras, digital video cameras, medical imaging devices, and automotive imaging devices. [0003] CMOS image sensors include front illuminated (FSI) image sensors and back illuminated (BSI) imag...

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Problems solved by technology

[0004] However, with the improvement of device integration, the density of pixel units in the image sensor increases, and the dark current between adjacent pixel units continues to increase, which affects the performance of the image sensor.

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