Stacked Image Sensor Pixel Pad Layout for Coupling Suppression
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Solution Overview
Problem
Coupling between neighboring pixel pads in stacked image sensors leads to performance degradation, hindering the reduction of planar area and improvement of resolution and signal processing speed.
Innovation Solution
The implementation of coupling suppression lines in a horizontal direction between pixel pads, electrically connected to ground structures, to suppress coupling between adjacent pixel pads in stacked image sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If pixel pads are placed close together in stacked image sensors to reduce planar area, then the planar area is reduced, but coupling between neighboring pixel pads occurs causing performance degradation
Solution Approach 1:
A ground structure is introduced as an intermediary element between neighboring pixel pads in the first substrate. This ground structure acts as a mediator that blocks the coupling of noise signals between adjacent pixel pads, thereby maintaining signal quality while allowing pixel pads to be placed close together for reduced planar area.
Solution Approach 2:
The harmful coupling effect between pixel pads is extracted and isolated by introducing a dedicated ground structure. The ground structure separates the electrical fields of neighboring pixel pads, removing the harmful interaction while preserving the compact layout.
2Measurement precision
If pixel pads are placed close together to improve resolution, then resolution is improved, but coupling between pixel pads increases causing performance degradation
Solution Approach 1:
The ground structure serves as an intermediary that enables high-resolution pixel arrangements by preventing noise coupling between closely spaced pixel pads, thus allowing improved resolution without sacrificing signal quality.
Solution Approach 2:
The ground structure creates an equipotential region between pixel pads, stabilizing the electrical environment and preventing noise interference, which enables closer pixel placement for higher resolution while maintaining signal integrity.
3Speed
If pixel pads are placed close together to increase signal processing speed, then signal processing speed is improved, but coupling between pixel pads causes performance degradation
Solution Approach 1:
The ground structure acts as a mediator that allows pixel pads to be positioned for optimized signal processing speed while preventing noise coupling, thus achieving high speed without compromising signal quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively reduces coupling between neighboring pixel pads, enhancing the performance of stacked image sensors by improving resolution and signal processing speed while minimizing the planar area.
Implementation Method 1
a first coupling suppression line extending in a first horizontal direction on a part of the first interlayer insulating layer of the first pixel region and the first ground region, penetrating between the first and second pixel pads, and electrically connected to the first ground structure
Data Source
AI summary
An image sensor includes a first structure and a second structure stacked on the first structure in a vertical direction, the first structure including first and second pixel pads electrically connected to first and second floating diffusion regions, respectively, and a first coupling suppression line penetrating between the first and second pixel pads, and electrically connected to the first ground structure, and the second structure including third and fourth pixel pads electrically connected to first and second source-follower gates, respectively; and a second coupling suppression line penetrating between the third and fourth pixel pads, and electrically connected to the second ground structure.