Magnetic Sensor Flux Guide Reset via Ultra-Thick Metal Coils
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Solution Overview
Problem
Magnetoresistive sensors with flux guides face challenges in maintaining optimal magnetization orientation due to exposure to large external magnetic fields, leading to reduced signal-to-noise ratio and increased power consumption, making them unsuitable for mobile applications.
Innovation Solution
A method is developed to fabricate a sensor device with a reset mechanism that includes forming ultra-thick metal coils to magnetize or demagnetize the flux guide to a predetermined orientation using a transistor assembly, allowing for reset operations with voltage less than 5 volts, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flux guide is used to guide out-of-plane field into in-plane magnetoresistive sensor, then the sensor can detect z-axis magnetic fields, but the uniform magnetization of the flux guide can be disturbed by large external magnetic fields, resulting in lower signal-to-noise ratio and offset shift
Solution Approach 1:
The patent applies preliminary action by implementing a reset mechanism that proactively restores the flux guide's uniform magnetization orientation after exposure to large external magnetic fields. The reset coil generates a controlled magnetic field that realigns the flux guide's magnetization before it affects sensor measurements, preventing degradation of signal-to-noise ratio and offset stability.
2Reliability
If a reset operation is performed to restore uniform magnetization of the flux guide, then the signal-to-noise ratio and offset reading are improved, but large operating currents are required, leading to large voltage overhead and significant power consumption
Solution Approach 1:
The patent applies parameter changes by optimizing the reset coil's physical parameters, specifically using an ultra-thick metal layer (5 micrometers) to reduce the coil's electrical resistance. This allows the reset operation to be performed with lower voltage (less than 5 volts) and reduced current, significantly decreasing power consumption while maintaining the effectiveness of the magnetization reset.
3Reliability
If large operating currents are used for reset operations, then the flux guide magnetization can be restored, but the sensor devices become unsuitable for mobile and smart phone applications due to high power consumption
Solution Approach 1:
The patent applies parameter changes by reducing the reset operation voltage to less than 5 volts through the use of ultra-thick metal interconnects with reduced resistance. This power optimization makes the sensor device suitable for mobile and smartphone applications where low power consumption is critical, while still achieving effective flux guide magnetization restoration.
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 enables efficient reset operations with low voltage, improving signal quality and reducing power consumption, making the sensor devices suitable for mobile and smartphone applications.
Implementation Method 1
The first metal coil and the second metal coil are configured as a reset mechanism that is configured to be responsive to the transistor assembly to magnetize or demagnetize the flux guide to the predetermined magnetic orientation
Data Source
AI summary
A magnetic field sensor structure includes a magnetoresistive sensor assembly and a transistor assembly. A dielectric layer is deposited on the transistor assembly. The dielectric layer includes a trench that exposes an interconnect of the transistor assembly. A damascene process is performed to form an ultra-thick metal (UTM) layer within the trench to create a first metal coil. The first metal coil is configured as a first reset component. Another dielectric layer is formed on the first metal coil. A flux guide is formed within the another dielectric layer. A second metal coil is formed over the another dielectric layer. The second metal coil is configured as a second reset component. The first reset component and the second reset component are configured as a reset mechanism, which is responsive to the transistor assembly and operable to magnetize the flux guide to a predetermined orientation.