Silicon Nitride Wafer Surface Roughness for Single Crystal Adhesion
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Solution Overview
Problem
Existing sintered silicon nitride wafers do not adequately adhere to single crystals, leading to issues such as peeling and positional shifts.
Innovation Solution
The sintered silicon nitride wafer is designed with a controlled surface roughness parameter (RSm) ranging from 100 µm to 350 µm, along with controlled roughness parameters Rv and Rt, to enhance adhesion and joining strength with single crystals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the surface roughness is increased to improve adhesion with single crystal, then the adhesion strength improves, but the manufacturing precision and surface quality deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the surface roughness parameters (RSm, Rv, Rt) within specific ranges. RSm is controlled at 100-350 μm, Rv at 0.02-2 μm, and Rt at 0.1-4 μm. This quantitative control of surface morphology parameters enables optimal adhesion to single crystals while maintaining manufacturing precision through defined measurement and control standards.
2Reliability
If the density at center and edge parts is controlled to improve insulation performance, then the dielectric strength improves, but the adhesion with single crystal becomes insufficient
Solution Approach 1:
The patent applies local quality by differentiating the requirements for different regions and aspects of the wafer. The density distribution is optimized for insulation performance in the bulk material, while the surface morphology (RSm, Rv, Rt parameters) is specifically engineered at the surface region to provide optimal adhesion properties. This allows the center and edge density to be controlled for dielectric strength while the surface roughness is independently optimized for single crystal adhesion.
Data Source
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AI summary
A sintered silicon nitride wafer according to an embodiment has a flat plate-shape. In the sintered silicon nitride wafer, at least one surface of the wafer has a mean value, of mean lengths RSm of a plurality of roughness profile elements having a length of a plurality of line segments passing through the center of the surface being taken as a standard length, within the range of 100 µm or larger and 350 µm or smaller.