Magnetoresistive Sensor Manufacturing with Sequential Laser Magnetization
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Solution Overview
Problem
Existing manufacturing methods for magneto resistive sensors face challenges in efficiently magnetizing multiple areas of antiferromagnetic layers without altering the previously set magnetization directions, especially as devices shrink in size and require closer spacing of magnetoresistance elements.
Innovation Solution
A manufacturing method involving two magnetization steps with laser annealing is employed, where a first area is magnetized in a specific direction and then a second adjacent area is magnetized in a different direction, with laser irradiation controlled to keep the first area's temperature below the blocking temperature, ensuring stable magnetization directions are maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple areas of antiferromagnetic layer are magnetized using conventional methods, then device functionality is achieved, but magnetization directions of previously magnetized areas may be altered due to thermal diffusion
Solution Approach 1:
The patent divides the magnetization process into distinct temporal segments - a first magnetization step that completes magnetization of a first area, followed by a second magnetization step for a second area. This temporal segmentation prevents thermal diffusion from affecting already-magnetized regions, as each area is magnetized in sequence rather than simultaneously, thereby maintaining magnetization direction control while ensuring magnetization stability.
Solution Approach 2:
The patent applies preliminary action by completing the magnetization of the first area entirely before initiating magnetization of the second area. This preliminary completion ensures that the first area's magnetization is established and stabilized before any thermal effects from subsequent processing could potentially alter it, thus resolving the contradiction between manufacturing precision and reliability.
2Productivity
If device size is reduced to improve integration, then productivity increases, but spacing between magnetoresistance elements decreases making magnetization control more difficult
Solution Approach 1:
By segmenting the magnetization process into sequential steps for different areas, the patent enables precise control over each region's magnetization direction even when areas are closely spaced. This segmentation allows the system to achieve high integration density while maintaining manufacturing precision, as each area can be magnetized independently without thermal interference affecting neighboring regions.
3Speed
If laser irradiation is applied to magnetize antiferromagnetic layer, then magnetization speed increases, but temperature control becomes critical to prevent altering existing magnetization
Solution Approach 1:
The patent segments the laser irradiation process into distinct temporal phases corresponding to different areas. By completing laser irradiation for the first area before initiating irradiation for the second area, the system maintains high magnetization speed through efficient sequential processing while achieving precise temperature control. This prevents thermal diffusion from affecting already-magnetized regions, resolving the contradiction between speed and manufacturing precision.
Solution Approach 2:
The patent maintains continuity of useful action by seamlessly transitioning from magnetizing the first area to magnetizing the second area without unnecessary interruptions. This continuous sequential process maximizes magnetization speed while the controlled timing ensures temperature remains within safe thresholds, preventing alteration of existing magnetization and achieving both high speed and manufacturing precision.
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 approach allows for precise magnetization of multiple areas with differing directions, enabling reduced device size and improved functionality by minimizing interference between adjacent areas.
Implementation Method 1
irradiating the first area with a laser beam
Implementation Method 2
applying a magnetic field in a first magnetization direction
Implementation Method 3
irradiating the second area with the laser beam
Implementation Method 4
irradiation with the laser beam is performed so that a maximum temperature of the first area remains below a blocking temperature
Data Source
AI summary
A manufacturing method for a magneto resistive sensor includes a first magnetization step for magnetizing a first area of an antiferromagnetic layer by applying a magnetic field in a first magnetization direction and irradiating the first area with a laser beam, and a second magnetization step for magnetizing a second area of the antiferromagnetic layer, the second area not overlapping the first area, after the first magnetization step by applying a magnetic field in a second magnetization direction that differs from the first magnetization direction and irradiating the second area with the laser beam.