Pixel Sensor Metal Grid Antireflection for Crosstalk Reduction
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Solution Overview
Problem
Optical crosstalk between adjacent pixel sensors in a pixel sensor array degrades spatial resolution, reduces sensitivity, causes color mixing, and leads to image noise in CMOS image sensors.
Innovation Solution
Incorporation of antireflection structures, including antireflective layers, nanostructures, and cavities in the metal grid surrounding pixel sensors to minimize light reflection and reduce optical crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If light reflection is minimized using antireflection structures, then quantum efficiency is enhanced, but device complexity increases
Solution Approach 1:
The antireflection structure is segmented into multiple discrete components: antireflective layers deposited on specific surfaces, nanostructures positioned at interfaces, and cavities formed in the metal grid. This segmentation allows each component to address specific reflection issues at different interfaces while maintaining manufacturing feasibility through modular fabrication processes.
Solution Approach 2:
The patent employs composite material structures combining metal grid layers with dielectric antireflective layers and nanostructured materials. This composite approach creates a multi-layered system where each material contributes specific optical properties to minimize reflection across different wavelengths and angles, thereby enhancing quantum efficiency through material composition rather than单一的复杂结构设计.
2Measurement precision
If optical crosstalk is reduced between adjacent pixel sensors, then spatial resolution is improved, but manufacturing precision requirements increase
Solution Approach 1:
The metal grid structure serves as an intermediary element positioned between adjacent pixel sensors. By depositing antireflective layers and forming cavities in this intermediate metal grid, the patent creates a buffering structure that optically isolates adjacent pixels without requiring direct modification of the pixel sensor boundaries themselves, thereby reducing the precision demands on critical pixel fabrication processes.
Solution Approach 2:
Instead of addressing optical crosstalk solely in the lateral plane between adjacent pixels, the patent introduces vertical dimensionality through cavities formed in the metal grid and multi-layered antireflective structures. This dimensional transition allows optical isolation to be achieved through vertical light path management rather than requiring tighter lateral spacing control, thereby reducing manufacturing precision requirements.
3Reliability
If antireflection structures are incorporated to reduce optical crosstalk, then sensitivity is improved, but ease of manufacture decreases
Solution Approach 1:
The antireflective layers are deposited on the metal grid structure before final pixel sensor assembly and integration. This preliminary action allows the antireflection functionality to be established during the metal grid fabrication stage, utilizing existing deposition equipment and processes rather than requiring additional specialized steps after pixel sensor completion, thereby maintaining manufacturing ease while achieving sensitivity improvement.
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
Enhances quantum efficiency and reduces optical crosstalk, thereby improving spatial resolution and sensitivity while minimizing color mixing and image noise in CMOS image sensors.
Implementation Method 1
a photodiode configured to convert photons of incident light into a photocurrent of electrons
Implementation Method 2
Incorporation of antireflection structures, including antireflective layers, nanostructures, and cavities in the metal grid surrounding pixel sensors to minimize light reflection and reduce optical crosstalk
Data Source
AI summary
An image sensor device may include one or more types of antireflection structures on a metal grid surrounding the pixel sensors in a pixel sensor array of the image sensor device. The antireflection structures may include an antireflective layer, nanostructures extending from the antireflective layer, and/or a plurality of cavities formed in the metal grid structure. The antireflection structures may be included in and/or on one or more surfaces of the metal grid structure to reduce the reflection of incident light, which may reduce the likelihood and/or magnitude of optical crosstalk between adjacent pixel sensors in the pixel sensor array.