Offcut Angle Determination via Electron Channeling Patterns
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Solution Overview
Problem
Conventional methods for determining crystal orientation, such as X-ray diffraction, are time-consuming and limited in accuracy and applicability, particularly for semiconductor devices where precise offcut angle determination is crucial.
Innovation Solution
The use of electron channeling patterns to efficiently determine the offcut angle by rotating a sample through multiple azimuthal setpoints or adjusting the electron beam orientation, allowing for rapid and accurate characterization of crystal orientation using scanning electron microscopy and pixelated electron backscatter diffraction detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional X-ray diffraction techniques are used to determine crystal orientation, then measurement accuracy can be achieved, but the determination time becomes excessively long
Solution Approach 1:
The patent replaces the conventional X-ray diffraction system with an electron beam-based channeling pattern system. By using electron beams incident at different azimuthal angles to generate channeling patterns, the method achieves rapid offcut angle determination (within minutes) while maintaining measurement accuracy, eliminating the time-consuming nature of X-ray diffraction techniques
Solution Approach 2:
The patent changes the measurement parameter from X-ray diffraction intensity to electron channeling pattern characteristics. By analyzing the angular dependence of electron channeling patterns at multiple azimuthal setpoints and determining the radius of the circular locus of zone axes, the method achieves both speed and accuracy in offcut angle measurement
2Measurement precision
If conventional X-ray diffraction is used, then crystal orientation can be determined, but the method is limited in accuracy and applicability for semiconductor devices
Solution Approach 1:
The patent employs electron channeling patterns with variable azimuthal angles instead of conventional X-ray diffraction parameters. By measuring the circular locus radius of zone axes from channeling patterns at multiple azimuthal setpoints, the method achieves 0.1° accuracy (or 0.01° with precision goniometers), meeting semiconductor device requirements while expanding applicability to various crystal orientations and device structures
Solution Approach 2:
The electron beam channeling pattern system can determine offcut angles for various crystal structures and orientations, making it universally applicable to different semiconductor devices. The method works for both simple and complex crystal systems, providing accurate offcut angle measurement across diverse semiconductor applications
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 significantly reduces determination time to minutes while achieving 0.1° accuracy, suitable for semiconductor applications, and can provide 0.01° accuracy with precision goniometers, enhancing the reliability and yield of semiconductor devices.
Implementation Method 1
electron channeling patterns
Implementation Method 2
pixelated electron backscatter diffraction detectors
Data Source
AI summary
Methods and apparatus determine offcut angle of a crystalline sample using electron channeling patterns (ECPs), wherein backscattered electron intensity exhibits angular variation dependent on crystal orientation. A zone axis normal to a given crystal plane follows a circle as the sample is azimuthally rotated. On an ECP image presented with tilt angles as axes, the radius of the circle is the offcut angle of the sample. Large offcut angles are determined by a tilt technique that brings the zone axis into the ECP field of view. ECPs are produced with a scanning electron beam and a monolithic backscattered electron detector; or alternatively with a stationary electron beam and a pixelated electron backscatter diffraction detector. Applications include strain engineering, process monitoring, detecting spatial variations, and incoming wafer inspection. Methods are 40× faster than X-ray diffraction. 0.01-0.1° accuracy enables semiconductor applications.