X-ray reflectometer with fixed detector and variable irradiation angle

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Solution Overview

Problem

Conventional X-ray reflectometers face challenges in obtaining a sufficient reflection angle range with sufficient X-ray intensity within a short time while minimizing background due to scattered X-rays, leading to inaccurate analysis.

Innovation Solution

An X-ray reflectometer with a focused X-ray beam formation unit, a slit to limit the focusing angle, a sample height setting unit, and an irradiation angle variable unit, combined with a position sensitive detector and reflection intensity calculation unit, allows for varying the irradiation angle and integrating detected intensities within a divergence angle width, reducing background and enhancing analysis accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a focused X-ray beam with a large focusing angle is used to broaden the reflection angle range, then the reflection angle range is improved, but background due to scattered X-rays increases

Engineering Contradiction:
Improvereflection angle rangeVSAvoidbackground due to scattered X-rays
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies dynamics by making the irradiation angle variable while keeping the detector fixed. The irradiation angle can be adjusted to optimize the reflection angle range for different samples, providing adaptability without requiring a large fixed focusing angle that would increase scattered X-ray background. This dynamic adjustment allows the system to maintain a narrow effective angle range while achieving wide measurement capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of irradiation angle dynamically to achieve different reflection angle ranges. By varying the irradiation angle rather than relying on a large focusing angle, the system can adapt to different measurement requirements without increasing the background from scattered X-rays. This parameter change approach resolves the contradiction between range and background.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a parallel X-ray beam is used, then the structure is simple, but the intensity of reflected X-rays is insufficient requiring longer measurement time

Engineering Contradiction:
ImprovestructureVSAvoidmeasurement time
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent uses a dynamically adjustable irradiation angle with a fixed focused X-ray source and detector. This dynamic configuration allows the system to maintain a simple fixed structure while optimizing the focused beam geometry for different measurements, achieving both structural simplicity and high measurement efficiency through the focused beam's superior intensity compared to parallel beams.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the X-ray source and detection unit are synchronously rotated, then the reflectivity curve can be obtained, but the structure becomes complicated and measurement time increases

Engineering Contradiction:
Improvereflectivity curveVSAvoidstructure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent inverts the conventional approach by keeping the detector fixed and varying the irradiation angle instead of rotating both source and detector synchronously. This inversion simplifies the structure by eliminating the need for synchronized rotation mechanisms while still obtaining the complete reflectivity curve through angle variation, thereby reducing both structural complexity and measurement time.

Inventive Principle:
Principle #13The other way round (Inversion)

4Illumination intensity

If a focused X-ray beam is used, then the intensity of reflected X-rays is sufficient, but the reflection angle range is limited by the focusing angle

Engineering Contradiction:
Improveintensity of reflected X-raysVSAvoidreflection angle range
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent resolves this contradiction by making the irradiation angle dynamic. The focused X-ray beam maintains its high intensity characteristics, while the variable irradiation angle allows the system to access a wide reflection angle range. This dynamic adjustment enables the focused beam to cover different angle ranges by changing the incidence angle, combining the advantages of both focused beam intensity and wide angle coverage.

Inventive Principle:
Principle #15Dynamics

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 configuration enables accurate analysis with sufficient X-ray intensity over a wide reflection angle range in a short time, while minimizing background noise from scattered X-rays, thus improving measurement precision.

Implementation Method 1

a focused X-ray beam formation unit having an X-ray source which emits X-rays

Methodology Applied
Scientific EffectX-ray emission: X-Ray

Implementation Method 2

a focusing device which focuses the X-rays from the X-ray source

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 3

for a reflected X-ray beam obtained by the focused X-ray beam being reflected by the sample

Methodology Applied
Scientific EffectX-ray reflection: Reflection

Data Source

PatentEP3550292B1X-ray reflectometer
Publication Date: 2021.10.27 RIGAKU CORP
  • EP3550292B1 patent drawingFigure 1
  • EP3550292B1 patent drawingFigure 2~3
  • EP3550292B1 patent drawing

AI summary

The X-ray reflectometer of the present invention includes: an irradiation angle variable unit (10) configured to vary an irradiation angle of a focused X-ray beam (6) with a sample surface (8a); a position sensitive detector (14) which is fixed; and a reflection intensity calculation unit (15) configured to, per reflection angle of reflected X-rays (13) constituting a reflected X-ray beam (12), integrate a detected intensity by a corresponding detection element (11), for only the detection elements (11) positioned within a divergence angle width of the reflected X-ray beam (12) in the position sensitive detector (14), in synchronization of variation in the irradiation angle (θ) of the focused X-ray beam (6) by the irradiation angle variable unit (10).