SiC Ingot Radial Cutting for Evaluation Sample
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Solution Overview
Problem
The existing methods for evaluating SiC single crystals result in significant loss of high-quality wafers due to the destructive cutting process, particularly from the distal end of the truncated cone portion, which reduces the yield of SiC wafers.
Innovation Solution
A method involving cutting the SiC ingot in the radial direction at a specific thickness position between the curved surface and the seed crystal, followed by polishing the silicon surface of the obtained head member to create a sample for evaluation, thereby minimizing the loss of high-quality wafers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wafer for evaluation is cut out from the distal end of the truncated cone portion, then the quality of the SiC wafer is improved, but a large loss is caused in the manufacturing of the SiC wafer
Solution Approach 1:
The invention extracts the evaluation function from the high-quality distal end region of the truncated cone portion. By cutting the head portion including the curved surface as a separate head member for evaluation purposes, the high-quality region can be fully utilized for product wafers without being consumed by evaluation samples, thereby reducing material loss while maintaining wafer quality.
Solution Approach 2:
The SiC ingot is segmented into two distinct parts: a head member containing the curved surface for evaluation purposes, and the truncated cone portion for product wafer manufacturing. This segmentation allows the evaluation function to be performed on a separate component, preserving the high-quality distal end region for productive use.
2Ease of manufacture
If the head portion including the curved surface is removed before cutting wafers, then the evaluation process is simplified, but the yield of SiC wafers is reduced
Solution Approach 1:
The invention segments the SiC ingot into a head member (containing the curved surface) and the truncated cone portion. This segmentation allows the evaluation process to be performed on the head member separately, simplifying the evaluation workflow while preserving the truncated cone portion for high-yield wafer production.
Solution Approach 2:
The evaluation function is extracted to the head member, which contains the curved surface. By performing evaluation on this separately cut head member rather than removing it before wafer cutting, the process becomes simpler while maintaining high wafer yield from the truncated cone portion.
3Measurement precision
If a wafer for evaluation is cut from the truncated cone portion, then destructive inspection can be performed, but high-quality wafers are lost
Solution Approach 1:
The evaluation function is extracted to the head member containing the curved surface. By performing destructive inspection on this separately obtained head member, accurate quality evaluation is achieved without compromising the quality of the remaining truncated cone portion wafers used for product manufacturing.
Solution Approach 2:
The SiC ingot is segmented into a head member for evaluation and a truncated cone portion for production. This allows destructive inspection to be performed on the evaluation sample without affecting the integrity and quality of the remaining wafers.
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 the acquisition of a sample for evaluation without reducing the yield of SiC wafers, enabling the use of high-quality wafers from the distal end for product manufacturing while maintaining productivity.
Implementation Method 1
a step of cutting a SiC ingot in a radial direction at a thickness position, which is located in a range from a curved surface which forms a distal end surface in a crystal growth direction to a seed crystal, to obtain a head member which includes the curved surface
Implementation Method 2
a step of polishing a silicon surface of the head member to obtain a sample for evaluation
Implementation Method 3
the SiC ingot used in the step is a SiC ingot in which SiC thereof is crystal-grown from a seed crystal along a c axis direction
Data Source
AI summary
A method of acquiring a sample for evaluation of a SiC single crystal, comprising: a step of cutting a SiC ingot in a radial direction at a thickness position, which is located in a range from a curved surface which forms a distal end surface in a crystal growth direction to a seed crystal, to obtain a head member which includes the curved surface, wherein the SiC ingot used in the step is a SiC ingot in which SiC thereof is crystal-grown from a seed crystal along a c axis direction; and a step of polishing a silicon surface of the head member to obtain a sample for evaluation.