Single-Chip Double-Axis Magnetoresistive Angle Sensor Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing double-axis magnetoresistive angle sensors require multiple chips for accurate measurement, leading to increased complexity and potential errors in positioning, and existing methods for manufacturing these sensors are cumbersome and prone to precision issues.
Innovation Solution
A single-chip double-axis magnetoresistive angle sensor is developed, featuring magnetoresistive angle sensing units with the same magnetic multi-layer film structure, arranged in a push-pull configuration with thermal-insulation gaps and a magnetic field attenuation layer, allowing for precise integration of X and Y-axis sensors on a common substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the flipped chip method is used to obtain X and Y axis sensing units, then the preparation method is simple and only one chip structure is needed, but at least 4 chips are required and precise positioning becomes complex increasing measurement accuracy loss
Solution Approach 1:
The patent merges multiple sensing units with different orientations onto a single chip substrate. The first and second magnetoresistive angle sensing units are fabricated on the same chip with their sensitive directions oriented at different angles (e.g., 0° and 90°), eliminating the need for separate flipped chips and their associated positioning errors.
Solution Approach 2:
The chip is segmented into multiple independent magnetoresistive angle sensing units, each with its own magnetic field sensitive direction. This segmentation allows each unit to be optimized for specific measurement directions while maintaining precise relative positioning through controlled fabrication processes.
2Measurement precision
If orthogonal ferromagnetic reference layers are fabricated using multi-layer film structure with two-time magnetic field thermal annealing, then the orientation can be controlled, but the micromachining process complexity increases due to four multi-layer film structures and two-time annealing
Solution Approach 1:
The patent changes the fabrication parameters by using a single magnetic field thermal annealing process instead of two-time annealing. By carefully designing the anti-ferromagnetic layer structure and controlling the annealing conditions, the magnetic field sensitive directions of multiple sensing units are established in one step, reducing process complexity while maintaining precise directional control.
3Adaptability or versatility
If a magnetic field attenuation layer is added to increase magnetic field measurement range, then the working magnetic field range is expanded, but the device structure becomes more complex
Solution Approach 1:
The magnetic field attenuation layer serves multiple functions: it extends the magnetic field measurement range, provides structural support, and can be integrated with the existing multi-layer film structure without requiring separate assembly steps. This multi-functionality approach expands capabilities while minimizing additional complexity.
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 solution enables a compact, high-precision, and cost-effective single-chip design with a larger magnetic field working range, reducing the complexity of micromachining processes and improving measurement accuracy.
Implementation Method 1
The magnetization direction of the anti-ferromagnetic layer is obtained by laser heating magnetic annealing
Implementation Method 2
a magnetic field is applied in any desired direction during the cooling process
Implementation Method 3
The magnetoresistive angle sensing unit is a TMR or GMR spin valve unit
Implementation Method 4
increases the magnetic field measurement range of a magnetoresistive angle sensing unit by adding a magnetic field attenuation layer on the surface
Data Source
AI summary
A single-chip two-axis magnetoresistive angle sensor comprises a substrate located in an X-Y plane, a push-pull X-axis magnetoresistive angle sensor and a push-pull Y-axis magnetoresistive angle sensor located on the substrate. The push-pull X-axis magnetoresistive angle sensor comprises an X push arm and an X pull arm. The push-pull Y-axis magnetoresistive angle sensor comprises a Y push arm and a Y pull arm. Each of the X push, X pull, Y push arm, and Y pull arms comprises at least one magnetoresistive angle sensing array unit. The magnetic field sensing directions of the magnetoresistive angle sensing array units of the X push, X pull, Y push, and Y pull arms are along +X, −X, +Y and −Y directions respectively. Each magnetoresistive sensing unit comprises a TMR or GMR spin-valve having the same magnetic multi-layer film structure. A magnetization direction of an anti-ferromagnetic layer is set into a desired orientation through the use of a laser controlled magnetic annealing, and a magnetic field attenuation layer can be deposited in the surface of the magnetoresistance angle sensing unit.