CMOS Magnetic Field Sensor with Multi-Layer Mass Block
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Solution Overview
Problem
Current micro magnetic field sensors can only measure magnetic forces in two directions, lacking the capability to detect forces in a third direction perpendicular to the plane, and existing solutions for three-axis measurement either require multiple sensors or complex structures, which are not efficiently integrated using standard CMOS processes.
Innovation Solution
A micro magnetic field sensor design that utilizes a single mass block with Y and Z direction displacement detection electrodes and a power supply module, integrated using a standard CMOS process, allowing for three-axis magnetic force measurement by detecting changes in capacitance through Lorentz forces generated by current and magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single mass block is used for magnetic field sensing, then device complexity and manufacturing cost are reduced, but the measurement capability is limited to single direction only
Solution Approach 1:
The patent extends the measurement capability from single direction to three-dimensional space by adding electrode pairs that detect displacement in multiple directions (X, Y, and Z axes). The mass block is equipped with electrodes that can sense movement along three orthogonal directions, transforming a one-dimensional sensor into a three-dimensional magnetic field sensor without requiring multiple separate mass blocks.
2Adaptability or versatility
If multiple mass blocks are used to achieve three-axis measurement, then measurement capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines three measurement functions (X, Y, and Z axis detection) into a single integrated mass block structure. Instead of using three separate mass blocks or sensor units, the invention merges all detection capabilities into one unified structure with multiple electrode pairs arranged to detect magnetic field components along three orthogonal directions simultaneously.
Solution Approach 2:
The single mass block is designed to perform multiple measurement functions by incorporating electrode pairs oriented in different directions. The same mass block structure serves as the sensing element for all three axes, making the sensor multi-functional and eliminating the need for separate sensor units for each measurement direction.
3Ease of manufacture
If standard CMOS process is used for manufacturing, then ease of manufacture and integration are improved, but achieving three-axis measurement with a single mass block becomes more difficult
Solution Approach 1:
The mass block is constructed using multiple metal layers and dielectric layers that are formed through sequential CMOS fabrication steps. Each layer pair can be independently patterned and deposited using standard CMOS processes, allowing the complex multi-layer structure to be built up incrementally through manageable fabrication stages rather than requiring a single complex processing step.
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
Enables accurate and efficient measurement of magnetic forces in all three axes using a single mass block, simplifying manufacturing and reducing power consumption while maintaining compatibility with standard CMOS processes, thus addressing the limitations of existing two-axis sensors.
Implementation Method 1
A magnetic field sensor using the Lorentz forces substantially comprises a mass block which is suspended on a structure or a substrate via a spring. When a certain current is applied to the mass block, the current and magnetic forces existing in the earth magnetic field or generated by other magnetic objects generate the Lorentz forces, that move the mass block in a direction perpendicular to the current direction and the magnetic force direction.
Implementation Method 2
An electrode for detection forms generally in a comb or finger shape which is staggered with a comb or finger shape formed by an edge of the mass block and maintained at intervals; and the space therebetween is equivalent to a capacitor. The electrode for detection can detect a change in capacitance due to a change in the relative position between the mass block and the electrode for detection caused by the movement of the mass block
Data Source
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AI summary
A magnetic field sensor, comprising a suspending mass block, a group of Y direction displacement sensors, a group of Z direction displacement sensors and a power supply; wherein the mass block, the Y direction displacement sensors and the Z direction displacement sensors respectively comprise a plurality of metal layers and a dielectric layer between two metal layers. In the mass block, a region corresponding to the Y direction displacement sensors and a region corresponding to the Z direction displacement sensors respectively comprise at least two metal layers connected by a via. The Y direction displacement sensors include two electrodes, each comprising at least two metal layers connected by a via; the Z direction displacement sensor includes two electrodes, each comprising at least two metal layers connected by a via; and the power supply provides a current flowing through the mass block selectively in X or Y direction.