Solid-State Imaging Device Light-Shielding Film and Buffer Layer
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Solution Overview
Problem
Solid-state imaging devices, particularly back-side illuminated (BSI) devices, face challenges in reducing total thickness and experiencing optical cross-talk issues due to the presence of light shielding layers and insulating layers between color filter layers and semiconductor substrates, which affects sensitivity and color mixture.
Innovation Solution
A light-shielding film is disposed on the same plane as the color filter layer, with a low refractive index buffer layer filling the space between adjacent color filter components and above the light-shielding film to reduce thickness and mitigate optical cross-talk, while a microlens structure is formed above the color filter layer to enhance optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light shielding layer and insulating layer are disposed between the color filter layer and the semiconductor substrate, then light blocking between pixels is improved, but the total thickness of the imaging device cannot be reduced
Solution Approach 1:
The light shielding layer and color filter layer are merged into a single integrated structure where the light shielding layer is formed on the same plane as the color filter layer. This combination eliminates the need for separate insulating layers between these components, reducing the overall thickness while maintaining effective light blocking between adjacent pixels through the integrated design
2Object-affected harmful factors
If the light shielding layer is disposed below the color filter layer with insulating layers, then color mixture prevention is improved, but device complexity increases
Solution Approach 1:
The light shielding layer and color filter layer are combined into a single integrated layer structure, reducing the number of separate layers and interfaces. This merger simplifies the overall device structure while maintaining effective color filtering and light blocking functions through the integrated design
Solution Approach 2:
The integrated light shielding and color filter layer serves multiple functions simultaneously: it blocks light between pixels, filters specific wavelengths for color separation, and eliminates the need for separate insulating layers. This multi-functionality reduces device complexity while maintaining performance
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
The solution effectively reduces the total thickness of the imaging device and minimizes optical cross-talk between adjacent pixels, improving sensitivity and optical performance by optimizing the arrangement of light-shielding and color filter components.
Implementation Method 1
a low refractive index buffer layer having a refractive index lower than that of the color filter layer to fill into a space between adjacent color filter components and above the light-shielding film
Implementation Method 2
a microlens structure disposed above the color filter layer
Implementation Method 3
photoelectric transducers such as photodiodes for converting light into electric charges
Data Source
AI summary
Solid-state imaging devices and fabrication methods thereof are provided. The solid-state imaging device includes a substrate containing a first photoelectric conversion element and a second photoelectric conversion element. A color filter layer has a first color filter component and a second color filter component respectively disposed above the first and second photoelectric conversion elements. A light-shielding partition is disposed between the first and second color filter components. The light-shielding partition has a height lower than that of the first and second color filter components. A buffer layer is disposed between the first and second color filter components and above the light-shielding partition. The buffer layer has a refractive index lower than that of the color filter layer.