Image Sensor Low-Refractive Pattern for Light Refraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current image sensors face challenges in maximizing light-receiving efficiency and achieving sharp image quality due to limitations in light refraction and protection of color filters, leading to issues like dark current and bruise defects.
Innovation Solution
The image sensor design incorporates a semiconductor substrate with deep device isolation, photoelectric conversion sections, color filters, a low-refractive pattern, and a protective layer, along with a light-shield pattern, to enhance light refraction and protect the filters, thereby increasing luminance efficiency and preventing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If color filters are placed close to each other to increase pixel density, then productivity and area utilization improve, but light refraction control deteriorates causing image quality degradation
Solution Approach 1:
A low-refractive pattern is introduced as an intermediary substance between adjacent color filters. This low-refractive pattern has a refractive index lower than both the color filters and the surrounding medium, creating optimal refraction conditions at the interfaces. This mediator enables close spacing of color filters while maintaining precise light control and image quality.
Solution Approach 2:
The refractive index parameter is strategically manipulated by introducing the low-refractive pattern with a specifically lower refractive index than the color filters. This parameter change creates favorable refraction conditions at the interfaces between color filters and the low-refractive pattern, enabling both high pixel density and sharp image quality.
2Ease of manufacture
If color filters are exposed during fabrication to enable subsequent processing, then ease of manufacture improves, but reliability deteriorates due to moisture absorption and damage
Solution Approach 1:
The sacrificial pattern is removed beforehand to create access pathways to the color filters before final encapsulation. This preliminary action enables subsequent processing steps to access and modify the color filters as needed, while the color filters remain protected during these operations.
Solution Approach 2:
The low-refractive pattern serves as a protective intermediary layer that covers the color filters after processing. This intermediary layer shields the color filters from environmental damage and moisture absorption, maintaining their reliability while allowing necessary processing access.
3Device complexity
If conventional fabrication processes are used without sacrificial patterns, then device complexity is reduced, but manufacturing precision deteriorates due to inability to control color filter spacing
Solution Approach 1:
Sacrificial patterns are formed in advance at precise positions where color filters will be deposited. These pre-formed sacrificial patterns serve as spacing templates, ensuring accurate spacing control during color filter fabrication. After color filters are formed, the sacrificial patterns are removed, leaving precisely spaced color filters without requiring complex real-time control mechanisms.
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 configuration improves light-receiving efficiency, raises the signal-to-noise ratio, and enhances image quality by effectively refracting light and protecting the color filters, resulting in improved reliability and reduced defects.
Implementation Method 1
a low-refractive pattern filling a space between the color filters... when a first light L1 is incident adjacently on edges of the first color filters CF1 and the second color filters CF2, the first light L1 may be refracted from a surface of the low-refractive patterns 25a
Implementation Method 2
Each of the pixels includes a photodiode. The photodiode serves to convert incident light into electrical signals.
Data Source
AI summary
An image sensor and a method of fabricating an image sensor are provided, the image sensor including a plurality of color filters spaced apart from each other on a semiconductor substrate; a protective layer covering sidewalls of the color filters and top surfaces of the color filters; and a low-refractive pattern filling a space between the color filters.