BSI Image Sensor Barrier Layer and Color Filter Structure
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Solution Overview
Problem
Back Side Illuminated (BSI) image sensors face challenges such as poor quantum efficiency, dark current, low full well capacity, and high yield loss due to increased complexity in manufacturing, which results in higher costs and material wastage, limiting their performance and efficiency.
Innovation Solution
The introduction of a semiconductor structure with a substrate, a barrier layer, and color filters that allow visible light to pass through while blocking non-visible light, enabling the detection of both visible and non-visible light components in electromagnetic radiation, and a method for manufacturing this structure that includes forming a substrate, disposing a barrier layer, and positioning color filters to enhance light sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If BSI image sensor manufacturing involves more complicated steps and operations with different materials, then functionality and integrated circuitry are enhanced, but manufacturing complexity increases causing poor quantum efficiency, dark current, low full well capacity, and high yield loss
Solution Approach 1:
The patent segments the manufacturing process into distinct stages: forming the substrate with photosensitive diodes, depositing the barrier layer, forming recesses, and filling with color filters. This segmentation allows each step to be optimized independently, reducing overall manufacturing complexity while maintaining enhanced functionality.
Solution Approach 2:
The patent introduces a vertical dimension by forming recesses in the substrate and filling them with color filters. This three-dimensional structure allows multiple functional layers to be integrated without increasing planar complexity, enabling enhanced functionality while controlling manufacturing difficulty.
2Adaptability or versatility
If BSI image sensor manufacturing involves more complicated steps and operations, then integrated circuitry is enhanced, but quantum efficiency deteriorates
Solution Approach 1:
The barrier layer serves as an intermediary between the substrate and color filters, preventing harmful interactions while allowing light to pass through. This intermediary structure protects the photosensitive diodes from degradation during manufacturing, maintaining quantum efficiency despite enhanced integrated circuitry.
Solution Approach 2:
The patent applies different materials and structures to different regions: the barrier layer is applied selectively over the substrate, and color filters are placed in specific recesses. This local quality approach ensures that quantum efficiency is maintained in photosensitive regions while allowing complex integrated circuitry in other areas.
3Adaptability or versatility
If BSI image sensor manufacturing involves more complicated steps and operations, then functionality is enhanced, but full well capacity decreases
Solution Approach 1:
The patent nests the color filters within recesses of the substrate, creating a nested structure where the color filters are embedded in the substrate volume. This nesting approach allows enhanced functionality without increasing the overall device size, preserving full well capacity by maintaining adequate photosensitive diode volume.
4Adaptability or versatility
If BSI image sensor manufacturing involves more complicated steps and operations, then integrated circuitry is enhanced, but yield loss increases
Solution Approach 1:
The patent performs preliminary actions by forming the barrier layer and recesses before introducing color filters. This preliminary structuring creates a robust framework that tolerates variations in subsequent manufacturing steps, reducing yield loss despite enhanced integrated circuitry functionality.
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 solution improves the accuracy of image reconstruction by allowing both visible and non-visible light to be sensed, reducing manufacturing complexities and costs, and enhancing the overall performance of BSI image sensors.
Implementation Method 1
a barrier layer... configured to block non-visible light from reaching the photosensitive diode
Implementation Method 2
color filters configured to allow visible light to pass through the color filter and the barrier layer
Implementation Method 3
Each pixel includes a photo-diode... Electrical energy is induced in the photo-diode upon exposure to light
Data Source
AI summary
A semiconductor structure includes a substrate, a barrier layer disposed over the substrate, a grid disposed over the barrier layer, and a first color filter disposed over the barrier layer. The semiconductor structure also includes a second color filter disposed over the substrate and laterally surrounded by and contacting the grid. The semiconductor structure further includes a dielectric layer disposed between the barrier layer and the substrate. The barrier layer includes an upper surface overlapping the grid and the first color filter and a bottom surface substantially level with a bottom surface of the second color filter. The dielectric layer includes a first portion overlapping a bottom surface of the first color filter and a second portion overlapping a bottom surface of the second color filter, wherein non-visible light is allowed to pass from the second color filter to the substrate through the second portion of the dielectric layer.