Backside Stimulated CMOS Biosensor Background Current
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Solution Overview
Problem
Conventional CMOS biosensors face challenges in detection sensitivity and accuracy due to the multiple layers of metals and dielectrics that increase system complexity and cost, and reduce sensitivity, while existing technologies rely on top metal layer signal transmission and conventional electrodes for measurement.
Innovation Solution
The implementation of backside-stimulated CMOS biosensors that utilize the background current to measure affinity-based binding effects by immobilizing bio-probes on the substrate's backside surface, allowing for signal detection without the need for top metal layer transmission and using the innate background current as a measurement tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional top metal layer signal transmission and electrodes are used, then signal detection is achieved, but detection sensitivity and accuracy are reduced
Solution Approach 1:
The patent inverts the conventional signal transmission approach by moving the bio-probes from the top metal layer to the substrate backside surface. This inversion eliminates the need for signal transmission through multiple metal layers, directly improving detection sensitivity while reducing system complexity. The backside-stimulated configuration allows direct electrical contact with the substrate, bypassing the complex metal interconnect structure.
Solution Approach 2:
The patent extracts the signal transmission path from the complex metal layer structure and eliminates it entirely. By placing bio-probes on the substrate backside, the invention removes the intermediate metal layers that previously conducted signals, thereby simplifying the system while enhancing detection capability.
2Measurement precision
If multiple layers of metals and dielectrics are used for signal transmission, then signal conduction is achieved, but detection sensitivity is reduced
Solution Approach 1:
The patent extracts and removes the signal transmission function from the multiple metal and dielectric layers. By placing bio-probes on the substrate backside with direct electrical contact, the invention eliminates the need for complex layered signal conduction structures, thereby improving detection sensitivity while reducing system complexity.
3Measurement precision
If conventional electrodes and top metal layer transmission are used, then measurement is achieved, but accuracy is reduced
Solution Approach 1:
The patent inverts the conventional measurement configuration by placing bio-probes on the substrate backside rather than using top metal layer transmission. This inversion provides direct electrical contact with the substrate, improving measurement accuracy by eliminating signal degradation through complex metal layers while simplifying the overall system structure.
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 detection sensitivity and accuracy by utilizing the background current to measure affinity-based effects at the backside surface, reducing system complexity and cost, and improving signal detection without the limitations of conventional top metal layer transmission.
Implementation Method 1
utilize their background current to measure affinity related stimuli to their backside surfaces
Data Source
AI summary
A CMOS (Complementary Metal Oxide Semiconductor) pixel for sensing at least one selected from a biological, chemical, ionic, electrical, mechanical and magnetic stimulus. The CMOS pixel includes a substrate including a backside, a source coupled with the substrate to generate a background current, and a detection element electrically coupled to measure the background current. The stimulus, which is to be provided to the backside, affects a measurable change in the background current.