A CMOS image sensor structure and method for preventing scribe short circuit

Abstract

The invention discloses a CMOS image sensor structure and formation method for preventing dicing short circuit. By arranging a composite isolation structure outside the internal circuit regions of a photosensitive chip and a logic chip, it includes a P-well implant formed in an n-type substrate of the photosensitive chip. region, the first P+ implantation region, the third metal interconnection layer structure, the fourth metal interconnection layer, the second P+ implantation region formed in the logic chip, and the combination of the third metal interconnection layer and the fourth metal interconnection layer The TSV structure with upper and lower electrical connection realizes the electrical connection between the p-type substrate of the logic chip and the P-well injection region in the n-type substrate of the photosensitive chip, and isolates the pixel unit in the n-type substrate for photosensitive The array area and the peripheral suspended n-type substrate area, when the silicon residue sinter formed by dicing forms residues on the sidewalls of the stacked chips, it only connects the suspended n-type substrate area and the p-type substrate, and does not Causes a short circuit from the power supply to ground or an increase in quiescent current.

Description

technical field [0001] The present invention relates to the technical field of CMOS image sensors, and more particularly, relates to a three-dimensional stacked CMOS image sensor structure and forming method that can prevent short circuit problems during silicon wafer scribing. Background technique [0002] An image sensor refers to a device that converts optical signals into electrical signals. Large-scale commercial image sensor chips include charge-coupled device (CCD) and complementary metal-oxide semiconductor (CMOS) image sensor chips. Compared with traditional CCD sensors, CMOS image sensors have the characteristics of low power consumption, low cost and compatibility with CMOS technology, so they are more and more widely used. CMOS image sensors are now not only used in consumer electronics such as miniature digital cameras (DSC), mobile phone cameras, video cameras and digital single-lens reflex cameras (DSLR), but also in automotive electronics, monitoring, biotech...

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Problems solved by technology

However, if the silicon residue sinter 10' remains on the side of the chip, due to the conductive effect of the silicon residue sinter, the n-type substrate used on the photosensitive chip side and the p-type substrate on the logic chip side will be short-circuited together to form A short-circuit path 15 from the power supply to the ground, resulting in an increase in the quiescent current of the chip and even a failure of the function

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