Wafer-Level Magnetic Sensor Layout for Weak-Field Differential Sensing
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Solution Overview
Problem
Magnetic sensor devices face challenges in achieving high accuracy and robustness against external disturbance fields while measuring weak magnetic fields and requiring mechanical compactness, often necessitating trade-offs between conflicting requirements such as range, accuracy, and sensitivity.
Innovation Solution
A magnetic sensor device comprising a first semiconductor substrate with a processing circuit and multiple sensor substrates, connected via redistribution layers, allowing for customized measurement of magnetic field components at distant locations without a printed circuit board, and enabling programmable functionality for various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensor substrates are used to measure magnetic fields at distant locations, then measurement range and accuracy are improved, but device complexity increases
Solution Approach 1:
The device is divided into multiple independent sensor substrates (first sensor substrate, second sensor substrate, third sensor substrate) that can be positioned at different locations. Each substrate contains magnetic sensors that measure local magnetic field components, allowing the system to achieve both extended measurement range and high accuracy through distributed sensing while keeping each individual substrate relatively simple
Solution Approach 2:
The patent transitions from a single-plane substrate arrangement to a three-dimensional spatial configuration where sensor substrates are positioned at different heights (first substrate at first height, second substrate at second height) and different locations. This vertical and spatial dimensionality enables measurement of magnetic fields at distant locations without requiring a large printed circuit board, thus improving measurement range while controlling device complexity
2Measurement precision
If sensor substrates are positioned far apart to measure weak magnetic fields, then sensitivity is improved, but mechanical compactness deteriorates
Solution Approach 1:
Instead of placing sensor substrates far apart in a single plane, the patent utilizes vertical stacking to achieve spatial separation. The first sensor substrate is positioned at a first height, the second sensor substrate at a second height, allowing sufficient distance for weak magnetic field measurement while maintaining a compact footprint in the horizontal plane. This vertical arrangement preserves mechanical compactness while achieving the required sensitivity
Solution Approach 2:
The patent implements a nested configuration where sensor substrates are arranged in a compact stacked formation. The first, second, and third sensor substrates are positioned in close proximity vertically, creating a compact assembly that maintains the necessary separation for sensitivity while minimizing the overall device volume. This nested arrangement allows the device to measure weak magnetic fields without sacrificing mechanical compactness
3Ease of manufacture
If a printed circuit board is used to connect sensor substrates, then electrical connectivity is achieved, but device complexity and size increase
Solution Approach 1:
The patent merges the substrate functions by directly connecting the first sensor substrate, second sensor substrate, and third sensor substrate to each other and to the processing circuit without requiring a separate printed circuit board. The substrates themselves serve as both structural support and electrical interconnection carriers, reducing device complexity and eliminating the need for additional PCB layers and routing while maintaining full electrical connectivity
Solution Approach 2:
The sensor substrates are designed to perform multiple functions simultaneously: they provide mechanical support for the magnetic sensors, serve as electrical interconnection carriers connecting different sensor elements and the processing circuit, and enable spatial positioning for magnetic field measurement. This multi-functionality eliminates the need for a separate printed circuit board, reducing overall device complexity while maintaining ease of manufacture
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 provides improved signal-to-noise ratio, reduced sensitivity to external disturbances, and the ability to measure weak magnetic fields, while maintaining mechanical compactness and flexibility for different applications, such as in E-bikes, automotive, and industrial uses.
Implementation Method 1
a first magnetic sensor configured for providing at least a first sensor signal, and a second magnetic sensor configured for providing at least a second sensor signal
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A wafer-level packaged magnetic sensor device (100) comprising: a first semiconductor substrate (109) comprising a processing circuit configured for receiving a plurality of sensor signals, and for determining at least one difference signal (ΔBz), and for providing an output signal derived from said difference signal; and a plurality of sensor substrates comprising a second semiconductor substrate (106a) with a first magnetic sensor (S1), and a third semiconductor substrate (106b) with a second magnetic sensor (52); the first semiconductor substrate (109) being arranged at a location between the plurality of sensor substrates; the substrates being electrically connected by means of at least one redistribution layer (RDL).