Shielding Blocks in Transcapacitive Sensor Routing Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitive sensor devices face noise and energy interference from active circuits located proximate to receiver electrodes, affecting signal quality, particularly in compact silicon sensor devices used for fingerprint sensing.
Innovation Solution
The implementation of a silicon sensor device with multiple metal and dielectric layers, where routing traces and shielding blocks are used to isolate receiver electrodes from noise and energy originating from circuit layers, improving signal-to-noise ratio and reducing device size while maintaining sensor array size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If active circuits are located proximate to receiver electrodes to reduce device size, then device size is reduced, but noise and energy from active circuits negatively affect signal quality
Solution Approach 1:
A shielding layer is introduced as an intermediary component between the receiver electrodes and active circuits. This shielding layer acts as a mediator that blocks electromagnetic noise and energy from the active circuits from reaching the receiver electrodes, while allowing the circuits to remain in close proximity for compact device design.
Solution Approach 2:
The solution moves from a planar two-dimensional layout to a three-dimensional stacked architecture with multiple metal layers separated by dielectric layers. The receiver electrodes are placed on one metal layer while active circuits are positioned on underlying circuit layers, creating vertical separation that reduces noise coupling while maintaining compact footprint.
2Measurement precision
If multiple metal layers with routing traces and shielding blocks are added to shield receiver electrodes, then signal quality is improved, but device complexity increases
Solution Approach 1:
The second metal layer is designed to serve dual functions: it provides routing traces for transmitting signals to transmitter electrodes and simultaneously acts as a shielding layer with shielding blocks to protect receiver electrodes from noise. This multi-functionality reduces the need for additional dedicated shielding layers, thereby limiting the increase in device complexity.
Solution Approach 2:
The routing trace layer and shielding layer are merged into a single metal layer (the second metal layer). The routing traces and shielding blocks coexist in the same metal layer, combining two previously separate functions into one integrated structure, which simplifies the overall device architecture compared to having separate layers.
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 configuration achieves smaller sensor die size, higher resolution, lower cost, and easier design with improved signal quality by effectively shielding receiver electrodes from noise and energy interference, enhancing the performance of capacitive sensors.
Implementation Method 1
A respective routing trace for a respective transmitter electrode is configured to shield respective portions of the plurality of receiver electrodes which correspond to a width of the respective transmitter electrode from energy and/or noise originating from the one or more circuit layers
Data Source
AI summary
A silicon sensor device includes: a plurality of metal layers; and a plurality of dielectric layers. Each of the plurality of metal layers is disposed on a respective dielectric layer, and wherein each of the plurality of metal layers is separated from an adjacent metal layer by a respective dielectric layer. The plurality of metal layers include: a first metal layer comprising a plurality of transmitter electrodes and a plurality of receiver electrodes; a second metal layer disposed beneath the first metal layer, wherein the second metal layer comprises a plurality of routing traces for the plurality of transmitter electrodes and a plurality of shielding blocks; and one or more circuit layers disposed beneath the second metal layer. A respective shielding block of the plurality of shielding blocks is configured to shield a respective portion of a respective receiver electrode of the plurality of receiver electrodes.