Polycrystalline SiC Carrier Substrate Thinning With Curvature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-quality monocrystalline silicon carbide (c-SiC) substrates are expensive and difficult to source in large quantities, and existing layer transfer methods for composite structures are complex and costly due to significant material removal and curvature issues during substrate thinning.
Innovation Solution
A method for manufacturing a polycrystalline silicon carbide (p-SiC) support substrate involving the growth of an initial p-SiC substrate on a seed, formation of a carbon stiffening film, seed removal, and controlled thinning to maintain grain size uniformity, reducing curvature and material waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thick p-SiC layer is produced by chemical vapor deposition and then thinned to create a support substrate, then the support substrate can be used for composite structures, but the removal of the seed substrate induces significant curvature that causes breakage or complicates the thinning process
Solution Approach 1:
The patent applies preliminary action by forming a stiffening film on the front face of the p-SiC layer before removing the seed substrate. This preventive measure counteracts the curvature that would otherwise develop during seed removal, making the subsequent thinning process feasible without breakage or excessive complexity
Solution Approach 2:
The patent changes the mechanical parameters of the p-SiC layer by introducing a stiffening film that modifies the stress distribution and curvature characteristics. This parameter change enables the thinning process to proceed without the seed removal-induced curvature problems
2Manufacturing precision
If substantial thinning of the p-SiC layer is performed to create the support substrate, then the desired thickness is achieved, but this results in significant material removal and high costs
Solution Approach 1:
The stiffening film is formed preliminarily to enable controlled thinning with minimal material removal. By preventing curvature during the process, the patent allows for more efficient material utilization and reduced waste
Solution Approach 2:
The patent enables the reuse of the seed substrate after the p-SiC layer is formed and thinned. The stiffening film facilitates this by maintaining structural integrity during the processes that would otherwise require discarding the seed, thereby recovering and reusing valuable substrate material
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
The method allows for the production of a cost-effective p-SiC support substrate suitable for composite structures with reduced material usage and simplified processes, maintaining mechanical integrity for subsequent composite manufacturing.
Implementation Method 1
the growth of an initial polycrystalline silicon carbide substrate on a graphite or silicon carbide seed
Data Source
Figure 1a~1c
Figure 1d~1f
Figure 2a~2c
AI summary
The invention relates to a method for fabricating a polycrystalline silicon carbide carrier substrate, comprising the following steps: a) growing an initial polycrystalline silicon carbide substrate on a seed of graphite or of silicon carbide; on conclusion of step a), the initial substrate having a free front face and a back face in contact with the seed, b) forming a stiffening carbon film on the front face of the initial substrate, the initial substrate having, in the plane of its front face and just before the formation of the stiffening film, a first average silicon carbide grain size, c) removing the seed, so as to free the back face of the initial substrate, the latter having, in the plane of its back face and just after the removal of the seed, a second average silicon carbide grain size, smaller than the first average size, d) thinning the back face of the initial substrate to a thickness for which the initial substrate has, in the plane of its thinned back face, a third average grain size equal to the first average grain size to within ± 30%, the thinned initial substrate forming the carrier substrate.