SiC Substrate Bow Control for Inner Periphery Transport
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Solution Overview
Problem
Existing methods for supporting SiC substrates and epitaxial wafers during transportation often result in defects such as sensor detection failure and adsorption failure, particularly when supported on their inner periphery.
Innovation Solution
Manufacturing SiC substrates with predetermined bow and warp ranges, specifically less than 40 μm and 60 μm respectively when supported on the inner periphery, and more than -40 μm when supported on the outer periphery, to minimize deflection and associated 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 transported, but defects such as sensor detection failure and adsorption failure occur due to deflection
Solution Approach 1:
The patent applies parameter changes by precisely controlling the bow and warp parameters of the SiC substrate within specific ranges (bow: -10 to 10 μm, warp: -5 to 5 μm). This parameter control ensures the substrate maintains adequate flatness when supported on its inner periphery during transportation, preventing sensor detection failures and adsorption failures while enabling reliable transport handling.
2Ease of manufacture
If the bow and warp of a SiC substrate are not controlled, then manufacturing is easier, but deflection occurs during transportation causing defects
Solution Approach 1:
The patent applies preliminary action by controlling the bow and warp parameters during the substrate manufacturing process itself, before transportation occurs. By pre-controlling these geometric parameters within specified ranges during fabrication, the substrate is prepared in advance to resist deflection during subsequent transportation when supported on its inner periphery, thereby preventing transportation-related defects without requiring additional corrective measures later.
3Manufacturing precision
If outer peripheral support is used, then bow can be controlled to be more than -40 μm, but the substrate may still experience insufficient defect reduction compared to inner peripheral support with optimized bow and warp
Solution Approach 1:
The patent applies local quality by differentiating the support characteristics and geometric control requirements for different regions of the substrate. When supported on the inner periphery, the substrate requires tighter bow and warp control (-10 to 10 μm bow, -5 to 5 μm warp) compared to outer peripheral support (> -40 μm bow). This localized quality control approach optimizes defect reduction effectiveness for each support configuration, with inner peripheral support providing superior protection against transportation defects when appropriate geometric parameters are maintained.
Data Source
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.