Image Sensor Trench Optical Path Reduces Cross-Talk
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Solution Overview
Problem
Current image sensor devices face issues with cross-talk phenomenon and low signal-to-noise ratio (SNR), affecting their performance in biomedical sensing applications.
Innovation Solution
The image sensor device incorporates a trench filled with high-refractive-index material in the dielectric layer, acting as an optical path to collect optical signals, which reduces cross-talk and improves SNR by total reflection of light within the trench and blocking of external noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional image sensor structure is used, then device complexity is low, but cross-talk phenomenon occurs and signal-to-noise ratio is low
Solution Approach 1:
The patent introduces a trench structure that divides the dielectric layer into separate regions, creating isolated optical paths for adjacent pixels. This segmentation prevents light from one pixel from interfering with adjacent pixels, thereby reducing cross-talk and improving signal-to-noise ratio without requiring complete redesign of the entire sensor architecture.
Solution Approach 2:
The trench filled with high-refractive-index material acts as an intermediary structure between adjacent pixels. It serves as both a physical barrier to block stray light and an optical waveguide to direct excitation light, mediating the interaction between light and photoelectric conversion units while maintaining structural integrity.
2Measurement precision
If trench with high-refractive-index material is added, then cross-talk is reduced and SNR is improved, but device complexity increases
Solution Approach 1:
The high-refractive-index material is selectively placed only in the trench regions between pixels, not throughout the entire device. This local application of special material properties provides precise optical control where needed (at pixel boundaries) while leaving other regions unchanged, thereby improving measurement precision with minimal increase in overall device complexity.
Solution Approach 2:
The patent combines the high-refractive-index material with the existing dielectric layer to create a composite structure. The trench is filled with material having refractive index higher than the surrounding dielectric, forming a composite optical path that guides excitation light while blocking stray light, thereby enhancing measurement precision through material composition rather than structural complexity.
3Productivity
If trench structure is introduced, then optical signal collection is improved, but manufacturing complexity increases
Solution Approach 1:
The trench structure and high-refractive-index material filling are integrated into the existing manufacturing process flow, performed as preliminary steps before final sensor assembly. By preparing the optical path structures early in the fabrication process, the patent enables efficient optical signal collection while avoiding complex post-processing steps that would increase manufacturing difficulty.
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 cross-talk between pixels, avoids color mixing, and enhances the signal-to-noise ratio by ensuring only excitation light enters the photoelectric conversion units while blocking external noise, thereby improving the overall performance of the image sensor device.
Implementation Method 1
The trench is an optical path to collect optical signals... The filling material is a high-refractive-index material... total reflection of light within the trench
Implementation Method 2
blocking of external noise... ensuring only excitation light enters the photoelectric conversion units while blocking external noise
Data Source
AI summary
An image sensor device is provided. The image sensor device includes a substrate, a plurality of photoelectric conversion units for collecting image signals disposed in the substrate, a first dielectric layer disposed upon the substrate, a plurality of metal layers disposed in the first dielectric layer, a trench disposed in the first dielectric layer and located between the adjacent metal layers, a filling material filled in the trench, a second dielectric layer disposed upon the first dielectric layer, and a light source or a detected object disposed over the second dielectric layer. The metal layer adjacent to the substrate is defined as a first metal layer. The metal layer adjacent to the top of the first dielectric layer is defined as a top metal layer. The trench extends from the top of the first dielectric layer towards the substrate to the first metal layer.