Multi-wavelength mirror X-ray analysis for low-content element detection
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Solution Overview
Problem
Conventional fluorescent X-ray analysis techniques face challenges in accurately measuring elements with low content in samples, such as silver in solder bumps, due to low emission of fluorescent X-rays and interference from diffracted X-rays, which degrades measurement accuracy.
Innovation Solution
A fluorescent X-ray analysis apparatus that focuses X-ray irradiation on a measurement target element and an adjacent element with a higher energy absorption edge value, using a multi-wavelength mirror to select X-rays within specific energy ranges to enhance excitation efficiency and a detection system with movable X-ray detectors to exclude diffracted X-rays, thereby increasing the detection intensity of fluorescent X-rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional X-ray irradiation is used to measure elements with low content, then the measurement can be performed, but the emission amount of fluorescent X-rays is small resulting in low measurement accuracy
Solution Approach 1:
The patent applies parameter changes by selecting specific X-ray energy values that correspond to the absorption edge of the measurement target element. By tuning the X-ray energy to match the absorption edge (e.g., Ag K-absorption edge at 25.5 keV), the excitation efficiency is maximized, thereby increasing the emission amount of fluorescent X-rays from low-content elements and improving measurement accuracy.
2Measurement precision
If the sample is irradiated with X-rays, then fluorescent X-rays are detected, but diffracted X-rays are simultaneously reflected and incident to the detector becoming noise
Solution Approach 1:
The patent applies local quality by using a multi-wavelength mirror that selectively reflects only specific X-ray energy ranges while transmitting or absorbing other energies. The mirror is designed with specific layer structures (e.g., alternating layers of high and low atomic number materials) to reflect only the desired fluorescent X-ray energies from the measurement target element, thereby filtering out diffracted X-rays and other noise in the local energy domain.
Solution Approach 2:
The multi-wavelength mirror serves as an intermediary component between the X-ray source and the detector. It mediates the X-ray spectrum by selectively reflecting only the desired energy ranges corresponding to the absorption edge of the measurement target element, thereby eliminating diffracted X-rays and other harmful radiation before they reach the detector.
3Adaptability or versatility
If multiple elements are measured simultaneously, then comprehensive analysis is achieved, but the measurement time increases reducing throughput
Solution Approach 1:
The patent applies segmentation by dividing the measurement process into separate sequential steps for different elements. The system first measures the measurement target element (e.g., Ag) by irradiating with X-rays at its absorption edge energy, then measures adjacent elements (e.g., Sn) by irradiating with X-rays at their respective absorption edge energies. This segmented approach allows comprehensive multi-element analysis while maintaining high throughput by optimizing each measurement 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 approach enables high-accuracy, high-throughput fluorescent X-ray analysis by enhancing excitation efficiency and reducing noise from diffracted X-rays, allowing for precise measurement of elements with low content in samples.
Implementation Method 1
a multi-wavelength mirror that extracts plural types of X-rays having different energy magnitudes upon incidence of continuous X-rays emitted from an X-ray source to the multi-wavelength mirror
Implementation Method 2
When Sn(tin) and Ag(silver) constituting these solder bumps are measured by fluorescent X-ray analysis, it has been impossible to perform the fluorescent X-ray analysis, particularly, on Ag with high accuracy because the emission amount of fluorescent X-rays emitted from Ag of a low content is small.
Implementation Method 3
an X-ray detection unit for detecting fluorescent X-rays emitted from the sample
Data Source
AI summary
This fluorescent X-ray analysis apparatus is provided with an X-ray irradiation unit 20 for irradiating a sample S with: X-rays, having an energy that exceeds the energy absorption edge value of Ag which is selected as a measurement target element, and that is no greater than the energy absorption edge value of Sn which is an adjacent element having a higher energy absorption edge value than Ag; and X-rays having an energy exceeding the energy absorption edge value of Sn which is selected as a measurement target element.