Semiconductor Fingerprint Sensor Flexible Substrate
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Solution Overview
Problem
Existing semiconductor fingerprint identification sensors face high costs, low signal-to-noise ratio, and poor reliability due to the use of single-crystal silicon substrates, and they have limitations in recognizing fake fingers and handling dry-wet fingers.
Innovation Solution
A semiconductor fingerprint identification sensor is developed using a flexible substrate with a sensor array made from high conductivity materials like copper or silver, embedded with a protective layer of high dielectric constant materials like Si3N4, and an ESD loop to minimize parasitic capacitance and enhance reliability, while integrating a fingerprint identification sensor circuit for accurate image processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If single-crystal silicon substrate is used for sensor array, then sensing performance is improved, but manufacturing cost increases sharply
Solution Approach 1:
The patent changes the substrate material parameter from single-crystal silicon to flexible substrate, and changes the sensor array material from single-crystal silicon to high conductivity material, thereby reducing manufacturing cost while maintaining sensing performance
Solution Approach 2:
The patent uses composite material structure with flexible substrate combined with high conductivity material for sensor array, and adds protective layer with high dielectric constant, creating a composite structure that achieves both cost reduction and performance maintenance
2Measurement precision
If single-crystal silicon substrate is used for sensor array, then sensing performance is improved, but signal-to-noise ratio decreases
Solution Approach 1:
The patent employs composite materials including flexible substrate, high conductivity material for sensor array, and protective layer with high dielectric constant, which together improve signal-to-noise ratio by reducing interference and enhancing signal transmission
Solution Approach 2:
The patent changes material parameters to high conductivity materials and adds protective layer with high dielectric constant, which improves electrical properties and signal-to-noise ratio
3Measurement precision
If single-crystal silicon substrate is used for sensor array, then sensing performance is improved, but reliability decreases
Solution Approach 1:
The patent uses composite material structure with flexible substrate, high conductivity sensor array material, and protective layer with high dielectric constant and high hardness, improving overall reliability through material optimization
Solution Approach 2:
The patent applies different material properties to different layers: flexible substrate for adaptability, high conductivity material for sensor array for signal quality, and high hardness protective layer for durability, optimizing each layer's local quality for overall reliability
4Measurement precision
If sensor area is increased, then fingerprint recognition capability is improved, but manufacturing cost increases sharply
Solution Approach 1:
The patent changes the substrate to flexible material and uses high conductivity materials for sensor array, which reduces the cost per unit area, allowing larger sensor areas without proportional cost increases
Solution Approach 2:
The composite material structure with flexible substrate and high conductivity layers reduces manufacturing cost, enabling expansion of sensor area for improved fingerprint recognition capability
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 reduces production costs, improves signal quality, and enhances recognition accuracy by using flexible substrates and high conductivity materials, while the ESD loop prevents static interference, addressing the limitations of existing sensors.
Implementation Method 1
A semiconductor fingerprint identification sensor mainly uses the principle of capacitance, inductance, temperature or pressure to achieve fingerprint image collection
Implementation Method 2
the semiconductor fingerprint identification sensor further comprises an electro-static discharge loop, wherein the electro-static discharge loop surrounds the sensing area
Data Source
Figure 1~2
AI summary
Disclosed are a semiconductor fingerprint identification sensor and a method for manufacturing the same. The semiconductor fingerprint identification sensor includes: a sensing area, a control area and an interface area; the sensing area, the control area and the interface area are communicated with one another; a fingerprint information sensed in the sensing area is sent to the control area, and is output through the interface area after being processed in the control area; the sensing area includes an insulation layer, an wiring layer, a substrate layer and a protective layer which are stacked in a sequence, the wiring layer is embedded between the insulation layer and the substrate layer, a sensor array is disposed on a side of the substrate layer being in contact with the protective layer, a via hole corresponding to the sensor array is disposed on the substrate layer, the sensor array is electrically connected with a sensing lead circuit of the wiring layer through the via hole. The semiconductor fingerprint identification sensor has advantages of low cost, high signal-to-noise ratio and good reliability.