Image Sensor Air Gaps Between Color Filters
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Solution Overview
Problem
Current CMOS image sensors face limitations in optical sensitivity, which affects their performance in various applications such as digital cameras and medical imaging devices.
Innovation Solution
The method involves fabricating an image sensor with a substrate having pixel regions, an anti-reflection layer, passivation layer, color filters, pyrolytic polymer patterns, and a capping layer, where the pyrolytic polymer patterns are removed through a thermal treatment process to create air gap regions between the color filters, enhancing optical sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If color filters are disposed close to each other to increase pixel density, then the pixel density is improved, but light reflection and scattering increase which reduces optical sensitivity
Solution Approach 1:
A pyrolytic polymer layer is introduced as an intermediary substance between adjacent color filters. This layer has low refractive index and acts as an optical mediator that reduces light reflection and scattering at the interfaces between color filters and the surrounding medium, thereby improving optical sensitivity while allowing color filters to be disposed close together for high pixel density
Solution Approach 2:
The refractive index parameter of the material between color filters is changed by using a pyrolytic polymer layer with low refractive index. This parameter change optimizes optical performance by minimizing reflection and scattering, allowing the color filters to be positioned closer together without sacrificing optical sensitivity
2Object-affected harmful factors
If a thermal treatment process is performed to remove pyrolytic polymer patterns and form air gap regions, then optical sensitivity is improved by minimizing light reflection, but the manufacturing process complexity increases
Solution Approach 1:
The pyrolytic polymer layer undergoes a phase transition through thermal treatment, transforming from a solid polymer state to a decomposed state that creates air gap regions. This phase transition is controlled and reversible, allowing the formation of air gaps that minimize light reflection while the process can be integrated into existing manufacturing workflows
Solution Approach 2:
The pyrolytic polymer layer is formed as a preliminary structure between color filters before final device assembly. This preliminary action creates a template that guides the subsequent thermal treatment process, ensuring uniform air gap formation and simplifying the overall manufacturing process by pre-positioning the material that will be transformed
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 increases optical sensitivity by minimizing light reflection and scattering, thereby improving the image sensor's performance and reducing crosstalk between pixels.
Implementation Method 1
performing a thermal treatment process that removes the pyrolytic polymer patterns and forms air gap regions between the color filters
Implementation Method 2
forming an anti-reflection layer on the substrate
Data Source
AI summary
A method of fabricating an image sensor includes providing a substrate that includes a plurality of pixel regions, forming an anti-reflection layer on the substrate, forming color filters on the anti-reflection layer, where the color filters are spaced apart from each other by openings, forming pyrolytic polymer patterns between the color filters that fill the openings, forming a capping layer on the color filters and the pyrolytic polymer patterns, and performing a thermal treatment process that removes the pyrolytic polymer patterns and forms air gap regions between the color filters.