BSI CMOS Biosensor Layout for DNA Sequencing Light Detection
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Solution Overview
Problem
Current biosensors for biological or chemical analysis face limitations in effectively measuring fluorescence or chemiluminescence, particularly in DNA sequencing applications, where precise detection and identification of nucleic acid macromolecules are required.
Innovation Solution
A backside illumination (BSI) complementary metal-oxide-semiconductor (CMOS) image sensor is employed, featuring a photo sensing layer with a substrate and photodiode, along with a color filter material and functionalized spots or wells to receive and analyze light emitted from nucleic acid macromolecules, enabling accurate measurement and identification through iterative processes like sequencing-by-synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional CMOS image sensors with front-side illumination are used, then the electronic circuit wiring can be placed on the same layer as the photodiodes, but the light must pass through the wiring and other components which causes destructive interference and reduces light detection efficiency
Solution Approach 1:
The patent inverts the traditional front-side illumination architecture to back-side illumination, where light enters the photodiode from the opposite side through which electrical contacts are made. This inversion allows the light path to be separated from the electronic circuit wiring, eliminating destructive interference while maintaining integration benefits
2Reliability
If backside illumination is used to place photodiodes closer to the light source, then light detection efficiency is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent transitions from planar integration to three-dimensional stacking, placing the photodiode layer above the electronic circuit layer vertically. This dimensional change allows both high light detection efficiency and integrated circuit functionality to coexist without requiring complex lateral routing
3Reliability
If more components are integrated onto the chip to direct more light into the photodiodes, then light capture efficiency is improved, but the area available for light capture is reduced
Solution Approach 1:
By inverting the illumination direction to back-side illumination, the patent eliminates the need for complex light-directing components in the light path. The photodiodes can be positioned directly in the light path without being obscured by wiring or other components, maximizing the light capture area
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 enhances the detection and analysis of fluorescence or chemiluminescence, facilitating efficient DNA sequencing and identification of nucleic acid macromolecules by correlating light parameters with specific labels, thereby improving the precision and efficiency of biological or chemical analysis.
Implementation Method 1
The light is received by the photodiodes on a substrate and transformed into electrical signals of different intensity
Data Source
AI summary
Embodiments of the invention provide an improved biosensor for biological or chemical analysis. According to embodiments of the invention, backside illumination (BSI) complementary metal-oxide-semiconductor (CMOS) image sensors can be used to effectively analyze and measure fluorescence or chemiluminescence of a sample. This measured value can be used to help identify a sample. Embodiments of the invention also provide methods of manufacturing an improved biosensor for biological or chemical analysis and systems and methods of DNA sequencing.