Image Sensor Pixel Separation Layout for ESD and Sensitivity
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Solution Overview
Problem
Highly integrated image sensors face challenges with defects such as ESD bruising due to charge accumulation, and existing solutions that form conductors between insulating layers can degrade the grid pattern's dispersion, reducing sensitivity.
Innovation Solution
The image sensor design includes conductor contacts that overlap only a part of the pixel separation pattern, specifically formed between the first portion and the grid pattern, while not being formed between the second portion and the grid pattern, to enhance sensitivity and reduce crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductor contacts are formed between the pixel separation pattern and the grid pattern, then charge accumulation and ESD bruising are prevented, but the grid pattern's dispersion is degraded and sensitivity is reduced
Solution Approach 1:
The conductor contacts are positioned to overlap only a first portion of the pixel separation pattern while deliberately avoiding overlap with a second portion. This local differentiation allows ESD protection in the first region while preserving grid pattern dispersion and sensitivity in the second region, resolving the contradiction between reliability and measurement precision.
2Reliability
If conductor contacts are formed between the pixel separation pattern and the grid pattern, then charge accumulation is prevented, but crosstalk between pixels is increased
Solution Approach 1:
The conductor contacts are strategically positioned to overlap only the first portion of the pixel separation pattern, creating localized charge dissipation paths. This prevents harmful charge accumulation while avoiding regions where crosstalk would be generated, thus resolving the contradiction between charge dissipation and crosstalk reduction.
3Reliability
If conductor contacts are formed in the surface insulating layer, then device protection is improved, but the fabrication process complexity increases
Solution Approach 1:
The conductor contacts are formed within the surface insulating layer during the insulating layer formation process itself, rather than requiring separate subsequent processing steps. This preliminary integration of the conductor contact formation into the existing fabrication sequence simplifies the overall process while maintaining device protection benefits.
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 increases the sensitivity and quality of the image sensor by improving the dispersion of the grid pattern and reducing crosstalk between pixels, while also simplifying the fabrication process.
Implementation Method 1
a plurality of pixels, each pixel including a photoelectric conversion layer in the substrate
Data Source
AI summary
An image sensor including: a substrate which includes a first surface and a second surface opposite each other; a plurality of pixels, each pixel including a photoelectric conversion layer in the substrate; a pixel separation pattern disposed in the substrate and separating the pixels; a surface insulating layer disposed on the first surface of the substrate; conductor contacts disposed in the surface insulating layer; and a grid pattern disposed on the surface insulating layer, wherein the pixel separation pattern includes a first portion and a second portion arranged in a direction parallel to the first surface of the substrate, and the conductor contacts are interposed between the first portion of the pixel separation pattern and the grid pattern and are not interposed between the second portion of the pixel separation pattern and the grid pattern.