A kind of 3D global pixel structure and preparation method thereof

Abstract

The invention discloses a 3D global pixel structure and a preparation method thereof, comprising a photoelectric signal generating circuit unit prepared on a first silicon substrate layer, a signal storage capacitor unit prepared on a second silicon substrate layer, and a photoelectric signal generating circuit The unit and the signal storage capacitor unit are arranged in the vertical direction, and the interconnection between the photoelectric signal generation circuit unit and the signal storage capacitor unit is realized through the connection relationship formed between the direct connection structure, the through hole, the metal layer wiring and the contact hole. connection; the present invention prepares three-dimensional unit structures at different levels by adopting back-illumination technology and 3D stacking structure, which can realize the vertical interconnection between the photoelectric signal generation circuit unit and the signal storage capacitor unit, thereby not only improving the distance between the outside world and the photodiode The optical path improves the optical isolation of the signal storage capacitor and reduces the chip area occupied by the pixel unit.

Description

technical field [0001] The invention relates to the technical field of semiconductor image sensing, and more particularly, to a high fill factor global shutter pixel unit with a 3D structure and a preparation method thereof. Background technique [0002] Traditional global shutter pixel technology is mainly used in CCD image sensors. Due to the increasing popularity of CMOS image sensors, and because machine vision, film production, industrial, automotive, and scanning applications must capture fast-moving objects with high Traditional barriers associated with shutter pixel technology. With this effort, the provided global shutter pixel technology has smaller pixel size, larger fill factor, lower dark current, and lower noise, making CMOS image sensors the preferred choice for CCD sensors in more applications. Viable alternatives. [0003] In the traditional global pixel, the photosensitive diode and the signal storage and readout circuit unit devices are all prepared in ...

AI Technical Summary

Problems solved by technology

Although this structure realizes the separation of the photodiode and other circuits of the pixel to reduce the pixel area, the photodiode, capacitor and readout circuit of the pixel need to be prepared in three parts, which is difficult to prepare and the structure is too complicated

And the path between the capacitor and the photodiode and the readout circuit is easier to introduce more parasitic resistance and capacitance, thereby increasing the readout noise of the pixel

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