Image Sensor

Abstract

The invention provides an image sensor. The image sensor comprises a device layer and a medium layer, wherein the device layer is provided with a first surface and a second surface, which are opposite to each other, and incidence light enters the device layer from the first surface; the medium layer is arranged on the second surface of the device layer, and the medium layer has high reflection characteristic. According to the image sensor, the light transmitted from the device layer can be reflected by the medium layer with high reflection characteristic to the device layer so as to be absorbed by the sensor, so that the absorption efficiency and light sensitivity of the long-wavelength light can be improved, a large-pixel monitoring device for collecting the image by utilizing the long-wavelength light can be favored, the probability for reflecting the transmission light to other pixels can be reduced, the signal interference of two adjacent pixels can be reduced, and the imaging effect of the image sensor can be improved.

Description

technical field [0001] The present invention relates to an image sensor. Background technique [0002] figure 1 Shows the structure of a traditional front-illuminated image sensor, as shown by the dotted line with arrows in the figure, after the incident light is converged by the microlens layer and filtered by the filter film layer, it first passes through the metal interconnection layer 104 and then enters the device layer 100 , which is absorbed by the photosensitive device 103 (such as a photodiode) in the device layer 100 and converted into an electrical signal, and is derived from the circuit formed by the metal interconnection layer 104 . Due to the shading of the metal interconnection layer 104 , part of the light is reflected or absorbed in the metal interconnection layer 104 , resulting in loss of incident light, reducing the amount of light received by the photosensitive device 103 , and further affecting the imaging effect of the image sensor. [0003] For this...

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Problems solved by technology

However, since the thickness of the device layer 200 is usually relatively small (2-3 μm), some long-wavelength light cannot be fully absorbed, resulting in low photosensitivity to long-wavelength light, and this part of long-wavelength light that is not absorbed is penetrating The device layer 200 is then reflected back to the device layer 200 in the metal interconnection layer 204. Due to the limitation of the process, there is inevitably a gap between the metal interconnection layer 204 and the device layer 200, and the direction of the reflected light is difficult to control. Therefore, It is easy to enter the photosensitive device 203 of adjacent pixels, causing crosstalk of signals between adjacent pixels, and finally resulting in a decrease in image sharpness and poor quality

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