Electron Probe Microanalyzer Positional Deviation Correction
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Solution Overview
Problem
In electron probe microanalysis, obtaining X-ray image data from the same region using different sequences of steps can result in positional deviations, leading to unreliable scatter diagrams due to potential shifts in the analyzed region caused by temperature variations or sample stage drifts, especially as resolution increases.
Innovation Solution
A method that involves obtaining and comparing sets of electron image data to calculate positional deviations, allowing for the extraction of a common region from X-ray image data sets obtained at different timings, and using this information to create accurate scatter diagrams by aligning the data sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If X-ray image data is obtained from the same region using different sequences of steps, then multiple measurements can be performed, but positional deviations occur due to temperature variations or sample stage drifts
Solution Approach 1:
The patent uses secondary electron images as reference copies to represent the original sample region positions. By capturing secondary electron images at different measurement timings and comparing them with the reference image, the system creates a digital copy of the positional information that can be used to detect and correct deviations without physically repositioning the sample.
Solution Approach 2:
The patent implements a feedback mechanism where positional deviations detected through image comparison are used to adjust the electron beam scanning positions. The system continuously monitors position drift by comparing secondary electron images and feeds this information back to correct the X-ray image acquisition positions, ensuring measurement accuracy is maintained across multiple sequences.
2Productivity
If the analyzed region shifts due to temperature variations or sample stage drifts, then measurement sequences can be completed, but scatter diagram reliability deteriorates
Solution Approach 1:
The patent performs preliminary capture of secondary electron images at the beginning of measurement sequences and uses these as reference images for subsequent position alignment. By preparing the reference data in advance, the system can later align X-ray images from different sequences to the same reference region, ensuring scatter diagram reliability even when measurements are completed at different times under varying temperature conditions.
3Measurement precision
If resolution is increased to improve image quality, then measurement accuracy improves, but positional deviations become more significant
Solution Approach 1:
The patent introduces secondary electron images as an intermediary medium between the sample and the X-ray analysis system. These intermediary images serve as position reference data that can be captured at low resolution without affecting the high-resolution X-ray measurements. The intermediary reference images allow the system to track positional deviations and correct them, enabling high-resolution measurements while maintaining positional stability across multiple sequences.
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
Enables the creation of reliable scatter diagrams by ensuring that X-ray images are obtained from the same region even when different sequences of steps are used, thereby maintaining data integrity and accuracy.
Implementation Method 1
a sample is irradiated with a sharply focused electron beam. The wavelength and strength of characteristic X-rays emanating from the sample are measured
Implementation Method 2
a wavelength-dispersive X-ray spectrometer (WDS) which is configured including a spectrometer for spectrally dispersing the characteristic X-rays
Implementation Method 3
By fixing the WDS detection wavelength at the characteristic X-rays of a certain element and scanning the electron beam across the analyzed region of the sample in two dimensions
Implementation Method 4
Secondary electrons produced from the sample 3 are detected by a secondary electron detector 5
Data Source
AI summary
In an electron probe microanalyzer (EPMA) and a method of use thereof, even if plural sets of X-ray image data are obtained at different timings from regions between which a positional deviation occurs, processing for obtaining the correlation is performed precisely. The sets of X-ray image data are obtained from the same region of a sample using the EPMA at different timings and stored in memory along with sets of electron image data based on detection of secondary or backscattered electrons arising from the region. The sets of electron image data obtained at the different timings are compared, and the amount of positional deviation is calculated. An operation for extracting a region common to the regions respectively producing the sets of X-ray image data obtained at the different timings is performed on these sets of X-ray image data based on the calculated amount of positional deviation.