Shared Metal Routing Lines for Imager Fill Factor
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Solution Overview
Problem
Imagers with anti-blooming and storage gate functionality suffer from decreased fill factor and quantum efficiency due to additional metal routing required for extra lines and transistors, which interferes with the optical path and reduces performance.
Innovation Solution
The solution involves combining metal routing lines within pixels and neighboring pixels to reduce metal routing, allowing for a larger area for the photosensor and its optical path, and increasing quantum efficiency by sharing signal lines to carry signals to and from multiple circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional metal routing lines and transistors are added to provide anti-blooming and storage gate functionality, then the imaging device gains electronic shuttering and blooming prevention capabilities, but the fill factor and quantum efficiency decrease due to increased metal routing interference with the optical path
Solution Approach 1:
The patent combines multiple metal routing lines into shared lines that serve multiple functions and multiple pixels. Specifically, a first shared metal routing line carries both a first control signal for a first transistor and a second control signal for a second transistor, while a second shared metal routing line carries both a third control signal for a third transistor and a fourth control signal for a fourth transistor. This merging reduces the total number of metal routing lines required, thereby reducing interference with the optical path and improving fill factor while maintaining anti-blooming and storage gate functionality.
2Adaptability or versatility
If additional metal routing lines and transistors are added to provide anti-blooming and storage gate functionality, then the imaging device gains electronic shuttering and blooming prevention capabilities, but the quantum efficiency decreases due to increased metal routing interference with the optical path
Solution Approach 1:
The patent combines multiple metal routing lines into shared lines that serve multiple functions and multiple pixels. Specifically, a first shared metal routing line carries both a first control signal for a first transistor and a second control signal for a second transistor, while a second shared metal routing line carries both a third control signal for a third transistor and a fourth control signal for a fourth transistor. This merging reduces the total number of metal routing lines required, thereby reducing interference with the optical path and improving quantum efficiency while maintaining anti-blooming and storage gate functionality.
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 approach reduces metal routing, enhances the area available for the photosensor, and increases quantum efficiency, thereby improving the performance of imagers by minimizing interference with the optical path.
Implementation Method 1
A CMOS imager includes a focal plane array of pixels, each pixel including a photosensor, for example, a photodiode, overlying a substrate for producing a photo-generated charge in a doped region of the substrate
Data Source
AI summary
An imaging device and method for operating the device. The imaging device comprises a pixel array having a plurality of pixels arranged in rows and columns. At least one pixel of the array comprises a photosensor and a first reset circuit responsive to a first reset control signal for resetting the photosensor. A first terminal of the first reset circuit is coupled to the photosensor and a second terminal of the first reset circuit is configured to receive a first resetting voltage from a control line.