A stacked image sensor

Abstract

The invention provides a stacked image sensor, which is composed of an upper silicon chip and a lower silicon chip through stacking technology, wherein the upper silicon chip is a photosensitive sensor array, the lower silicon chip is a readout circuit and an output interface, and the upper and lower silicon chips are connected by binding line connected. The lower silicon wafer of the stacked image sensor is a readout circuit and an output interface. The readout circuit and output interface circuit of the entire stacked image sensor, including digital-to-analog converters, analog-to-digital converters, amplifiers, row and column controllers, digital algorithms, high-speed data interfaces, bandgap references, etc., are all contained in the lower silicon chip. By adopting a stacked image sensor, the high readout circuit and high-speed output circuit are transferred to the lower silicon chip of the stacked sensor, thereby effectively reducing the area of ​​the non-pixel array area in the upper silicon chip. The photosensitive fill rate of a single silicon chip can be improved by stacking the image sensor, which realizes low noise and low power consumption of the sensor chip, and greatly improves the fill factor of the photosensitive sensor pixel array.

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 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] 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 front-illumination technology is to fabricate photosensitive diodes, metal interconnections, and light pipe holes (Light Pipe) in sequence on the front of the silicon wafer. Its advantages are: simple process, fully compatible with CMOS proces...

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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