SiC Substrate Evaluation at Low Electron Beam Incident Angles
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Solution Overview
Problem
Conventional methods for evaluating large-diameter silicon carbide (SiC) substrates require large measurement devices and struggle with electron beam defocusing and focal point deviation due to the need for a 30° to 40° inclination angle, making them costly and impractical for cost-effective production.
Innovation Solution
An evaluation method involving an electron beam incident at an angle of 10° or less relative to the {0001} plane of the SiC substrate, combined with an oxide film removal step and exposure to ambient air for 60 minutes or less, to acquire accurate brightness information on the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the stage is inclined at 30° to 40° to acquire the image, then the stacking direction can be evaluated, but the measurement device becomes large and the electron beam is easily defocused
Solution Approach 1:
The invention changes the incident angle parameter from the conventional 30° to 40° to 10° or less. This parameter change allows the electron beam to incident on the SiC substrate at a smaller angle, reducing the required stage inclination and thereby reducing the measurement device size while still enabling stacking direction evaluation through brightness information
2Measurement precision
If the stage is inclined at 30° to 40° to acquire the image, then the stacking direction can be evaluated, but the electron beam is easily defocused when scanning large-diameter substrates
Solution Approach 1:
The invention changes the incident angle parameter from 30° to 40° to 10° or less. This smaller incident angle reduces the height direction movement when scanning large-diameter substrates, thereby suppressing focal point deviation and maintaining electron beam focusing reliability throughout the scanning area
3Device complexity
If the incident angle is reduced to 10° or less, then the device size is reduced, but the brightness information clarity may be affected
Solution Approach 1:
The invention applies preliminary oxide film removal treatment to the SiC substrate surface before measurement. This preliminary action removes the oxide film that would otherwise interfere with the electron beam interaction, ensuring that clear brightness information reflecting the stacking direction can be obtained even at the reduced incident angle of 10° or less
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 allows for a compact measurement device, reduces focal point deviation, and enhances the clarity of brightness information, enabling efficient evaluation of large-diameter SiC substrates with reduced device costs and improved accuracy.
Implementation Method 1
making an electron beam incident at an incident angle inclined with respect to a normal line of a {0001} plane of a SiC substrate, the incident angle being 10° or less
Data Source
AI summary
An object of the present invention is to provide a novel evaluation method suitable for evaluating a SiC substrate having a large diameter.The present invention is a method for evaluating a silicon carbide substrate, the method comprising an image acquisition step of acquiring an image by making an electron beam incident at an incident angle inclined with respect to a normal line of a {0001} plane of a silicon carbide substrate, wherein the incident angle is 10° or less.