Stacking-type image sensor pixel structure and preparation method

Abstract

The invention discloses a stacking-type image sensor pixel structure and a preparation method. A first silicon wafer to a third silicon wafer is upwards and downwards stacked together by using a bonding mode. The first silicon wafer positioned on the middle layer is provided with a first light sensitive diode array. The second silicon wafer positioned on the upper layer is provided with a second light sensitive diode array. The surface of each second light sensitive diode in the second light sensitive diode array is aligned to and bonded with the surface of each first light sensitive diode inthe corresponding first light sensitive diode array, so a formed stacking-type image sensor chip has a very deep junction depth, is particularly suitable for near-infrared light sensitization, and capable of effectively improving quantum efficiency in a near infrared waveband; and through using a back illumination technology, enabling incident light irradiated to the light sensitive diode not to be affected by metal interconnection. The stacking-type image sensor chip is higher in sensitivity, higher in fill factor, and has a very good photosensitive property to a small-size image element especially, so the stacking-type image sensor chip is capable of giving consideration to the near infrared quantum efficiency, and the small pixel size.

Description

technical field [0001] The present invention relates to the technical field of image sensors, and more particularly, to a stacked near-infrared image sensor pixel structure and a preparation method thereof. Background technique [0002] Image sensors are an important part of digital cameras. According to the different components, it can be divided into two categories: CCD (Charge Coupled Device, charge-coupled device) and CMOS (Complementary Metal-Oxide Semiconductor, metal oxide semiconductor device). A prerequisite for the wide application of CMOS sensors is their higher sensitivity, shorter exposure time and shrinking pixel size. [0003] Among them, pixel sensitivity, one of the important performance indicators of CMOS image sensors, is mainly determined by the product of fill factor (the ratio of photosensitive area to the entire pixel area) and quantum efficiency (the number of electrons generated by photons bombarding the screen). In CMOS image sensors, in order to ...

AI Technical Summary

Problems solved by technology

Due to the influence of the pre-process, it is usually impossible to achieve a deep junction depth, and it cannot have a good sensitivity to near-infrared or quantum efficiency.

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