Magnetoresistive Sensor Reference Layers for Single-Step Phase Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current manufacturing processes for magnetoresistive sensors with magnetoresistive devices of different phases are complex and costly, as they require additional process steps to achieve desired magnetization directions, limiting the production of sensors with varied reference directions.
Innovation Solution
A method involving the formation of an initial reference layer in an annular shape, subjected to a heat treatment to magnetize the ferromagnetic layer along a vortex path and generate an exchange bias, followed by patterning to create separate reference layers and forming spacer and free layers to fabricate magnetoresistive devices with different phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional process steps are used to form GMR/TMR devices with different reference directions, then manufacturing precision is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent segments the magnetoresistive sensor into multiple magnetoresistive devices with different reference directions, where each device is formed from a separate reference layer. These reference layers are obtained by patterning an initial reference layer that has been subjected to heat treatment to create different exchange bias orientations in different regions, enabling precise control of magnetization directions without additional complex processing steps.
Solution Approach 2:
The patent applies preliminary action by performing heat treatment on the initial reference layer before patterning to establish different exchange bias orientations in different regions. This preliminary magnetization orientation step enables subsequent fabrication of multiple magnetoresistive devices with different reference directions using standard processing, avoiding the need for additional complex steps later in the manufacturing process.
2Manufacturing precision
If multiple heat treatment steps are applied to achieve different magnetization directions, then manufacturing precision is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent merges multiple heat treatment operations into a single heat treatment step that simultaneously creates different exchange bias orientations in different regions of the initial reference layer. This is achieved by designing the initial reference layer structure and applying heat treatment in a way that different regions develop different magnetization directions in one unified process, significantly reducing manufacturing cycle time compared to sequential heat treatment approaches.
Solution Approach 2:
The patent creates a universal heat treatment process that serves multiple functions: it simultaneously magnetizes different regions of the reference layer with different orientations, prepares the reference layers for subsequent patterning, and establishes the exchange bias needed for precise magnetization control in the final devices, eliminating the need for multiple separate processing steps.
3Productivity
If a single heat treatment step is used to produce magnetoresistive devices with different phases, then productivity is improved, but manufacturing precision may be compromised
Solution Approach 1:
The patent applies local quality by designing the initial reference layer with spatially varying properties that result in different exchange bias orientations in different regions after heat treatment. This local differentiation enables precise control of magnetization directions in specific areas of the reference layer, maintaining high manufacturing precision even though all regions are processed simultaneously in a single heat treatment step.
Solution Approach 2:
The patent utilizes parameter changes in the initial reference layer structure and heat treatment conditions to achieve different magnetization directions in different regions. By carefully controlling parameters such as layer composition, thickness, and heat treatment temperature and duration, the process achieves precise magnetization orientation control while maintaining high productivity through a single unified 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
This method simplifies the manufacturing process by enabling the production of magnetoresistive sensors with multiple phases using a single heat treatment step, reducing complexity and cost while maintaining the sensitivity to external magnetic fields.
Implementation Method 1
subjecting the initial reference layer to a heat treatment, wherein the ferromagnetic layer is magnetized and has a magnetization direction oriented along a vortex path during a heating step of the heat treatment, and an exchange bias oriented along the vortex path is generated at an interface between the antiferromagnetic layer and the ferromagnetic layer during a cooling step of the heat treatment
Implementation Method 2
an exchange bias oriented along the vortex path is generated at an interface between the antiferromagnetic layer and the ferromagnetic layer
Data Source
AI summary
A magnetoresistive sensor and a manufacturing method thereof are provided. The method includes: forming an initial reference layer in an annular shape, wherein the initial reference layer includes an anti-ferromagnetic layer and a ferromagnetic layer; performing a heat treatment on the initial reference layer, wherein the ferromagnetic layer is magnetized to have a magnetization direction oriented along a vortex path during a heating step of the heat treatment, and an exchange bias oriented along the vortex path is induced at an interface of the anti-ferromagnetic layer and the ferromagnetic layer during a cooling step of the heat treatment; patterning the initial reference layer to form separated reference layers, wherein the reference layers are respectively formed in a annular sector shape, and the reference layers are arranged along the vortex path; forming spacer layers and free layers to form magnetoresistive devices; routing the magnetoresistive devices to form the magnetoresistive sensor.