SiC Substrate Bow Control for Inner-Periphery Transport
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Solution Overview
Problem
Existing methods for supporting SiC substrates during transportation fail to sufficiently reduce defects such as bow and warp, particularly when supported on the inner periphery, leading to issues like sensor detection failure and transport errors.
Innovation Solution
Manufacturing SiC substrates with predetermined bow and warp ranges when supported on both inner and outer peripheries, specifically controlling the bow to be less than 40 µm and warp to be less than 60 µm for inner peripheral support, and ensuring the bow is more than -40 µm but 0 µm or less for outer peripheral support, while maintaining a diameter of 145 mm or more, to minimize deflection and transport errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a SiC substrate is supported on its inner periphery during transportation, then the substrate can be handled and transported, but deflection and warp occur causing sensor detection failure and adsorption failure
Solution Approach 1:
The patent specifies precise parameter ranges for bow (less than 40 μm) and warp (less than 60 μm) to ensure the substrate maintains adequate flatness during inner periphery support transportation, preventing sensor detection failure while enabling handling
2Ease of manufacture
If a SiC substrate is supported on its outer periphery during heat process, then the substrate can be processed, but bow and warp occur causing deflection
Solution Approach 1:
The patent specifies bow should be more than -40 μm (i.e., within 40 μm of flatness) when supported on outer periphery, balancing the substrate's ability to undergo heat processing with maintaining sufficient flatness to prevent deflection
3Productivity
If the SiC substrate has larger diameter (195 mm or more), then productivity and device performance improve, but the substrate becomes more prone to deflection during transportation
Solution Approach 1:
The patent establishes specific bow (< 40 μm) and warp (< 60 μm) tolerance ranges that scale appropriately for large diameter substrates (145 mm or more, preferably 195 mm or more), enabling high-performance device fabrication while maintaining transportation stability
Data Source
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AI summary
In a SiC substrate of the present invention, in a case where the SiC substrate is supported on an inner periphery by an inner peripheral support surface positioned to overlap a circumference having a radius of 17.5 mm from a center, in a case where a plane connecting first points of an upper surface overlapping the inner peripheral support surface when seen in a thickness direction is defined as a first reference plane, and an upper side of the first reference plane is defined as a positive side, a bow is less than 40 µm.