Stack type image sensor

Abstract

The invention provides a stack type image sensor. The stack type image sensor is formed by an upper silicon chip and a lower silicon chip via the stack technology, wherein the upper silicon chip is a photosensitive sensor array, the lower silicon chip is a readout circuit and output interface, the upper silicon chip and the lower silicon chip are connected via a binding wire, the lower silicon chip of the stack type image sensor is the readout circuit and output interface, and a readout circuit and output interface of the whole stack type image sensor comprises a digital-to-analog converter, analog-to-digital converters, an amplifier, a row / column controller, a digital algorithm, a high-speed data interface, and a band-gap reference included in the lower silicon chip. By employing the stack type image sensor, the high-readout circuit and the high-speed output circuit are transferred to the lower silicon chip of the stack type sensor so that the area of a non-pixel array area in the upper silicon chip is effectively reduced, the photosensitive filling rate of the single silicon chip can be increased, low noise and low power consumption of sensor chips are realized, and the filling factor of a photosensitive sensor pixel array is greatly increased.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a stacked image sensor. Background technique [0002] Image sensors are an important part of digital cameras. According to different components, it can be divided into two categories: CCD (ChargeCoupledDevice, charge-coupled device) and CMOS (ComplementaryMetal-OxideSemiconductor, metal-oxide-semiconductor element). A prerequisite for the wide application of CMOS sensors is their higher sensitivity, shorter exposure time and shrinking pixel size. [0003] The front side illumination (FSI, Front Side Illumination) technology adopted by the traditional CMOS image sensor is the front illumination technology. The main feature of the front-illumination technology is to fabricate photosensitive diodes, metal interconnections and light pipe holes (LightPipe) in sequence on the front of the silicon wafer. Its advantages are: simple process, fully compatible with CMOS process; lo...

AI Technical Summary

Problems solved by technology

However, the fill factor and sensitivity of front-illuminated technology is usually low because the light first needs to pass through the metal interconnection on the upper layer to reach the photodiode below

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