Polycrystalline SiC Plate Orientation Control for Low Warpage
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Solution Overview
Problem
Polycrystalline SiC formed bodies used in plasma etching applications require high flatness to ensure uniform processing, but existing methods fail to adequately control the orientation of crystal planes, leading to warpage and uneven surfaces.
Innovation Solution
Control the area fraction differences of specific crystal plane orientations between the main surfaces of the polycrystalline SiC formed body to within 10.0% or less, specifically for regions R200, R311, R111, and R220, using a CVD method with controlled deposition conditions to minimize internal stress and warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CVD methods are used to form polycrystalline SiC layers, then manufacturing efficiency is maintained, but the flatness of the formed body deteriorates due to uncontrolled crystal plane orientation and warpage
Solution Approach 1:
The invention changes the parameters of crystal plane orientation distribution by controlling the area fractions of specific crystal planes ((111), (200), (220), (311)) during CVD formation. By adjusting deposition conditions such as temperature, pressure, and gas composition, the patent achieves uniform crystal orientation between opposite surfaces, reducing warpage and improving flatness without fundamentally changing the CVD process complexity
Solution Approach 2:
The invention introduces feedback control by measuring the area fractions of different crystal planes on both surfaces of the formed body and adjusting the CVD parameters accordingly. This closed-loop approach allows real-time optimization of crystal orientation to maintain flatness within specified tolerances (difference in area fraction ≤10.0% for R200 and R311)
2Productivity
If crystal growth is accelerated to improve productivity, then manufacturing speed increases, but internal stress accumulates causing warpage and reducing flatness
Solution Approach 1:
The invention optimizes the balance between formation speed and flatness by adjusting CVD parameters (temperature, pressure, gas flow rates) to achieve appropriate crystal growth rates. By controlling the deposition conditions, the patent enables faster formation while maintaining uniform crystal orientation and minimizing internal stress accumulation that causes warpage
3Manufacturing precision
If the polycrystalline SiC layer is made thicker to reduce internal stress, then warpage decreases, but the area fraction difference of crystal planes between surfaces increases, deteriorating flatness
Solution Approach 1:
The invention changes the approach from thickness control to orientation control by adjusting CVD parameters to achieve uniform crystal plane distribution throughout the layer thickness. By optimizing deposition conditions, the patent ensures that the area fractions of specific crystal planes remain consistent from one surface to the other, achieving flatness without relying solely on increased thickness
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
Achieves a polycrystalline SiC formed body with enhanced flatness, reducing warpage to an absolute value of 30 μm or less, suitable for applications requiring uniform processing surfaces.
Implementation Method 1
a method comprising forming a polycrystalline SiC layer on a substrate by a CVD method
Data Source
AI summary
The present invention provides a polycrystalline SiC formed body excellent in flatness, and a method for manufacturing the same; it is a substantially plate-shaped polycrystalline SiC formed body comprising a first main surface and a parallel second main surface, the polycrystalline SiC formed body including, along a normal direction to the first main surface, a region R200, a region R311, a region R111, and a region R220 in which a (200) plane, a (311) plane, a (111) plane, and a (220) plane are oriented, respectively; and along a normal direction to the second main surface, a region R200, a region R311, a region R111, and a region R220 in which a (200) plane, a (311) plane, a (111) plane, and a (220) plane are oriented, respectively, wherein an area fraction of region RXYZ=area of region RXYZ/(area of region R111+area of region R200+area of region R220+area of region R311) and region RXYZ is any one of region R111, region R200, region R220, and region R311, wherein at least one of a difference between an area fraction of region R200 in the first main surface and an area fraction of region R200 in the second main surface being 10.0% or less and a difference between an area fraction of region R311 in the first main surface and an area fraction of region R311 in the second main surface being 10.0% or less is satisfied.