Polycrystalline Silicon Carbide Substrate Separation for Reusable Growth Bases
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Solution Overview
Problem
The high production costs of polycrystalline silicon carbide substrates due to the wastage of underlying substrates in chemical vapor deposition methods, which increases the overall cost of silicon carbide semiconductor production.
Innovation Solution
A method involving forming a carbon layer on an underlying substrate, depositing a polycrystalline silicon carbide film using CVD, exposing and burning the carbon layer to separate the film, and reusing the underlying substrate, thereby reducing waste and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the chemical vapor deposition method is used to form polycrystalline silicon carbide films on underlying substrates, then the film quality and crystal structure are improved, but the underlying substrates are wasted and production costs increase
Solution Approach 1:
The patent introduces a reusable carbon-based intermediate substrate that can be recovered and reused multiple times. The polycrystalline silicon carbide film is formed on this intermediate substrate, then separated through edge grinding and combustion of the carbon layer, allowing the underlying substrate to be reused without waste
Solution Approach 2:
The patent uses a carbon-based intermediate substrate as a mediator between the final product and the underlying substrate. This intermediate layer allows the film to be formed and then easily separated through combustion, protecting the underlying substrate from being wasted
2Manufacturing precision
If monocrystalline silicon carbide substrates are used as seed crystals in the improved Rayleigh method, then crystal growth control and defect reduction are improved, but production costs increase due to low growth rates and high processing costs
Solution Approach 1:
The patent replaces expensive monocrystalline silicon carbide substrates with a cheaper carbon-based intermediate substrate that serves the same function of supporting film growth. The carbon substrate is consumed in the separation process, but it is much less expensive than monocrystalline substrates
Solution Approach 2:
The patent changes the material parameter of the substrate from monocrystalline silicon carbide to carbon-based material. This parameter change maintains the ability to support high-quality film growth while dramatically reducing substrate cost and enabling faster processing
3Adaptability or versatility
If bonding methods are used to join monocrystalline and polycrystalline silicon carbide substrates, then substrate availability is improved, but oxide film formation at the bonding interface increases vertical electrical resistance
Solution Approach 1:
The patent extracts and removes the problematic oxide film formation by using a carbon-based intermediate substrate that is combusted away during separation. This eliminates the bonding interface and associated oxide film issues entirely
Solution Approach 2:
The carbon-based intermediate substrate serves as a mediator that prevents direct bonding between monocrystalline and polycrystalline substrates, thereby eliminating oxide film formation at the interface while still enabling substrate availability
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
This method allows for the reuse of underlying substrates, significantly reducing production costs without compromising the quality of the polycrystalline silicon carbide substrates, making them more viable for high-voltage and high-power semiconductor applications.
Implementation Method 1
burning the exposed carbon layer in an oxygen-containing atmosphere and separating the polycrystalline silicon carbide film from the second underlying substrate from which the carbon layer has been removed
Implementation Method 2
depositing a polycrystalline silicon carbide film using CVD
Data Source
Figure 1A~1F
Figure 2~3
AI summary
The present invention provides a method for producing a polycrystalline silicon carbide substrate 33 capable of reducing production costs without changing the quality of the polycrystalline silicon carbide substrate. The method includes: a carbon layer forming step of forming a carbon layer 21 on a surface of a first underlying substrate 11 to produce a second underlying substrate 12; a polycrystalline silicon carbide film forming step of forming a polycrystalline silicon carbide film 31 on a surface of the second underlying substrate by a chemical vapor deposition method; a carbon layer exposing step of removing an outer peripheral edge of the polycrystalline silicon carbide film formed on the surface of the second underlying substrate to expose the carbon layer; and a polycrystalline silicon carbide film separating step of burning the exposed carbon layer in an oxygen-containing atmosphere and separating the polycrystalline silicon carbide film from the second underlying substrate from which the carbon layer has been removed. By reusing the first underlying substrate without losing it, the production cost of the polycrystalline silicon carbide substrate can be reduced.