Pixel Isolation Structure for Image Sensor Crosstalk Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As pixel sizes in image sensors decrease, crosstalk between pixels increases, leading to potential sensor defects and reduced performance, particularly in auto focusing applications where accurate signal separation is crucial.
Innovation Solution
The image sensor design incorporates a pixel isolation structure with a conductive layer and an insulating layer, along with a signal separation structure that includes an insulating layer, to prevent crosstalk and improve light reception, featuring a substrate with a pixel isolation trench that penetrates from the first surface to the second surface and micro lenses on the second surface corresponding to pixel regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size is decreased to improve resolution, then image quality improves, but crosstalk between pixels increases
Solution Approach 1:
The patent applies segmentation by dividing the pixel array into isolated pixel regions using pixel isolation structures. These structures physically separate adjacent pixels, preventing photocharge leakage and crosstalk while maintaining small pixel dimensions for high resolution imaging.
Solution Approach 2:
The patent implements local quality by creating distinct isolation regions with different material properties (conductive layer with liner layer) at specific locations between pixels. This localized structural modification provides targeted crosstalk prevention without affecting the overall pixel design and light reception efficiency.
2Object-generated harmful factors
If pixel isolation structures are added to prevent crosstalk, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the pixel isolation structure: the conductive layer provides electrical isolation, the liner layer provides physical containment and stress relief, and together they form the pixel isolation structure that defines pixel regions. This integration reduces the need for separate isolation components, simplifying the overall device structure despite the sophisticated isolation mechanism.
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
This design effectively reduces crosstalk between pixels, enhances light reception, and improves auto focusing capabilities by ensuring accurate signal separation and reduced sensor defects, thereby maintaining image quality and functionality.
Implementation Method 1
a plurality of photoelectric conversion regions on the plurality of sub pixel regions
Data Source
AI summary
An image sensor including a substrate including a first and second surface; a pixel isolation structure penetrating the substrate, arranged in a pixel isolation trench extending from the first to second surface of the substrate, and defining a pixel region; a plurality of sub pixel regions on the pixel region; a plurality of photoelectric conversion regions on the plurality of sub pixel regions; a signal separation structure between the plurality of sub pixel regions, the signal separation structure being in a signal separation trench extending from the second surface of the substrate toward the first surface of the substrate into the substrate; and a micro lens on the second surface of the substrate, the micro lens corresponding to the pixel region, wherein the signal separation structure includes an insulating layer, and the pixel isolation structure includes a conductive layer; and a liner layer between the conductive layer and the substrate.