3d global pixel unit and preparation method thereof

Abstract

The invention provides a 3D global pixel unit and a preparation method thereof. The 3D global pixel unit comprises a photosensitive unit manufactured on a first silicon substrate layer and a signal storage and read-out circuit manufactured on a second silicon substrate layer, wherein the photosensitive unit and the signal storage and read-out circuit are arranged in the vertical direction; and interconnection of the photosensitive unit and the signal storage and read-out circuit is achieved through connection of a first dielectric layer and a second dielectric layer and connection of a first direct connection structure and a second direct connection structure. By adopting a back-illuminated technology and a 3D structure, vertical interconnection of the signal storage and read-out circuit and a photosensitive diode can be achieved by manufacturing three-dimensional unit structures on different levels, so that an optical channel of the outside and the photosensitive diode is improved, the optical isolation of a signal storage capacitor is improved, and furthermore, the chip area occupied by the pixel unit is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor image sensing, in particular to a 3D global pixel unit 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 global shutter pixel unit of a conventional CMOS image sensor, the photosensitive diode and the signal storage and readout circuit unit devices are all made in the same plane. T...

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Problems solved by technology

Moreover, the photosensitive unit, the storage capacitor and the readout circuit tend to interfere with each other

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