Clear Pixel Dielectric Integration for Image Sensor Cross-Talk
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Solution Overview
Problem
The manufacturing process of image sensors with color filter layers is complicated and costly due to separate fabrication steps for colored elements, clear elements, and light-blocking structures, and clear photoresist materials are susceptible to defects and do not provide an ideal transmission profile.
Innovation Solution
The use of a color filter layer with clear elements formed from transparent dielectric materials like silicon dioxide, silicon nitride, or silicon oxynitride, and color filter container structures formed from the same material as the clear elements, which reduces the need for additional layers and simplifies the manufacturing process by utilizing high refractive index differences to prevent cross-talk between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate fabrication steps are used for colored elements, clear elements, and light-blocking structures, then each component can be optimized independently, but the manufacturing process becomes complicated and costly
Solution Approach 1:
The patent merges the clear elements and light-blocking structures into a single integrated color filter layer formed from transparent dielectric material. This integration eliminates the need for separate fabrication steps while maintaining the functional distinction between clear elements and light-blocking structures through material property variations within the same layer.
Solution Approach 2:
The transparent dielectric material serves multiple functions simultaneously: it forms the clear elements for light transmission, creates light-blocking structures through refractive index differences, and provides structural support. This multi-functionality reduces manufacturing steps while maintaining component optimization.
2Ease of manufacture
If clear photoresist materials are used for clear elements, then the manufacturing process is simplified, but the materials are susceptible to defects and do not provide an ideal transmission profile
Solution Approach 1:
The patent changes the material parameter from organic photoresist to inorganic transparent dielectric materials such as silicon dioxide, silicon nitride, or silicon oxynitride. This material substitution eliminates the defect susceptibility of photoresist while maintaining ease of manufacture through standard semiconductor fabrication processes like CVD or PECVD.
Solution Approach 2:
The patent uses transparent dielectric materials that combine the benefits of inorganic material stability with processability through existing semiconductor manufacturing techniques. These materials provide superior transmission profiles and defect resistance compared to organic photoresist while remaining compatible with standard fabrication processes.
3Object-affected harmful factors
If additional light-blocking structures are added between elements, then cross-talk between pixels is prevented, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the light-blocking function from separate structural elements and integrates it directly into the color filter layer through refractive index differences. By taking out the need for additional light-blocking structures and embedding the light-blocking capability within the existing color filter material, the design prevents cross-talk without increasing structural complexity.
Solution Approach 2:
The patent uses refractive index differences of the transparent dielectric material as an intermediary mechanism to prevent cross-talk. Instead of adding physical light-blocking structures, the refractive index variation within the same material layer serves as a mediator to guide light and prevent cross-talk between adjacent pixels.
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 simplifies the manufacturing process, reduces defects, and improves the transmission profile, leading to more efficient and cost-effective image sensors with reduced cross-talk between pixels.
Implementation Method 1
utilizing high refractive index differences to prevent cross-talk between pixels
Data Source
AI summary
An image sensor may include an array of pixels having a color filter layer. The color filter layer may include colored elements and clear elements. The clear elements may be formed from transparent dielectric material. The color filter layer may include a grid of light-blocking material that forms color filter container structures having an array of openings in which the colored elements and the clear elements are formed. The color filter container structures may be formed from the same transparent dielectric material that forms the clear elements. The color filter container structures may be formed from opaque materials or transparent materials that form structures such as planarization layers, microlenses, or antireflection coatings for the array of pixels. The material used to form the color filter container structures may have a refractive index that is sufficiently high to prevent light from passing between adjacent elements in the color filter layer.