Gradient-Field Magnetic Measurement for Faster Spatial Characterization
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Solution Overview
Problem
Existing methods for measuring magnetic characteristics of magnetoresistive memory devices, such as FMR and MOKE, require significant measurement time due to the need to sweep static magnetic fields and AC currents at single points, leading to prolonged measurement periods.
Innovation Solution
A device incorporating a gradient magnetic field generator and a high-frequency magnetic field generator, along with actuators and a measuring unit, allows for simultaneous measurement of magnetic characteristics across multiple positions, reducing the need for sequential point measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical measurement using magneto-optical Kerr effect is used to measure magnetic characteristics, then measurement sensitivity is improved, but measurement time increases to 10-30 seconds per point
Solution Approach 1:
The patent divides the measurement space into multiple discrete measurement points arranged in a grid pattern across the wafer surface. Each point is measured sequentially by moving the measurement probe to different positions, allowing parallel measurement across multiple locations while maintaining the sensitivity of point-by-point optical measurement.
Solution Approach 2:
The patent transitions from single-point measurement to two-dimensional spatial measurement by introducing both X and Y directional movement of the measurement probe. This enables measurements to be taken across the entire wafer surface in a systematic grid pattern, dramatically increasing the number of measurement points that can be evaluated.
2Measurement precision
If FMR method is used to measure magnetic characteristics, then anisotropic magnetic field and damping coefficient can be measured, but measurement time exceeds several minutes due to sweeping static magnetic field and frequency at single point
Solution Approach 1:
The patent segments the measurement process into multiple discrete positions across the wafer surface. Instead of performing the time-consuming FMR measurement at a single point, the measurement probe visits multiple segmented locations, performing FMR measurements at each point to extract anisotropic magnetic field and damping coefficient values throughout the sample area.
Solution Approach 2:
The patent adds spatial dimensions to the FMR measurement process by implementing X and Y directional movement of the measurement probe. This transforms the measurement from a single-point technique to a multi-point spatial mapping technique, enabling comprehensive characterization of magnetic properties across the entire wafer surface.
3Measurement precision
If sequential point measurements are performed to examine magnetoresistive memory devices, then measurement precision is maintained, but productivity decreases due to prolonged measurement periods
Solution Approach 1:
The patent divides the wafer surface into multiple measurement points arranged in a systematic grid pattern. The measurement probe sequentially visits each segmented location, performing complete FMR measurements at each point. This segmentation allows comprehensive coverage of the wafer surface while maintaining the precision of point-by-point measurements.
Solution Approach 2:
The patent introduces two-dimensional spatial movement (X and Y directions) to the measurement process. This enables the measurement probe to systematically traverse the entire wafer surface, visiting multiple measurement points in each row and column, thereby dramatically increasing the number of devices that can be characterized per unit time.
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 device significantly shortens measurement time by enabling concurrent measurement of magnetic characteristics across a range of positions, improving throughput and sensitivity while maintaining high precision.
Implementation Method 1
a first magnetic field generator configured to generate a gradient magnetic field having a different magnetic field depending on a position
Implementation Method 2
an analysis method called ferromagnetic resonance (FMR) has been also known as a means of measuring magnetic characteristics
Implementation Method 3
a second magnetic field generator configured to generate a high-frequency magnetic field that is time-varying
Implementation Method 4
optical measurement utilizing a magneto-optical effect called a magneto-optical Kerr effect (MOKE) has been known
Data Source
AI summary
A device for measuring magnetic characteristics, includes a first magnetic field generator generating a gradient magnetic field having a different magnetic field depending on a position; a second magnetic field generator generating a high-frequency magnetic field that is time-based variable; a first actuator moving the second magnetic field generator; a mount mounting a test object; a second actuator moving the mount; and a measuring unit measuring the magnetic characteristics of the test object moving in the gradient magnetic field.