Silicon Carbide Epitaxial Layer Transfer via Thermal Separation
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Solution Overview
Problem
The process of transplanting a silicon carbide epitaxial layer to another substrate often results in loss of subsequent process yield and increases the difficulty in defect measurement.
Innovation Solution
A silicon carbide wafer manufacturing method involving forming a silicon carbide epitaxial layer, creating a thermal separation layer through ion implantation, bonding to a temporary substrate, heating to decompose the thermal separation layer, and performing chemical mechanical polishing (CMP) processes to separate and refine the epitaxial layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the silicon carbide epitaxial layer is bonded to another substrate for transplantation, then the substrate can be reused and production capacity can be increased, but the subsequent process yield is lost and defect measurement becomes more difficult
Solution Approach 1:
The patent divides the epitaxial layer into two separate layers through thermal separation, allowing each layer to be independently processed and measured. This segmentation enables defect measurement on separate layers rather than on a bonded structure, resolving the measurement difficulty while maintaining the ability to transplant layers to new substrates for continued production
Solution Approach 2:
The patent extracts the upper epitaxial layer from the bonded structure through thermal separation, allowing it to be independently processed. This extraction enables separate defect measurement of the upper layer before transplantation, eliminating the measurement difficulty associated with bonded structures while preserving the transplantation capability for production capacity
2Productivity
If the silicon carbide epitaxial layer is bonded to another substrate for transplantation, then the substrate can be reused and production capacity can be increased, but defect measurement becomes more difficult
Solution Approach 1:
The patent segments the bonded epitaxial layer structure into two separate layers through thermal separation. This allows defect measurement to be performed on the separated upper layer using standard techniques, eliminating the measurement difficulties associated with inspecting bonded interfaces and enabling continued production capacity through substrate reuse
3Ease of manufacture
If ion implantation is used to form a thermal separation layer, then the epitaxial layer can be separated into upper and lower layers for improved processing, but an additional process step is required
Solution Approach 1:
The patent changes the physical-chemical parameters of the epitaxial layer through ion implantation, creating a thermal separation layer with distinct decomposition characteristics. This parameter change enables controlled separation of the epitaxial layer into upper and lower portions, improving processing quality by allowing independent handling of each layer despite the added process step
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 effectively separates the silicon carbide epitaxial layer into upper and lower layers, allowing for high-quality silicon carbide wafers to be produced with improved yield and reduced defect measurement challenges.
Implementation Method 1
using an ion implantation process to form a thermal separation layer in the silicon carbide epitaxial layer
Implementation Method 2
heating the silicon carbide epitaxial layer causes the thermal separation layer to decompose and the silicon carbide epitaxial layer is separated into an upper silicon carbide epitaxial layer and a lower silicon carbide epitaxial layer
Implementation Method 3
performing a first chemical mechanical polishing process on the upper silicon carbide epitaxial layer bonded to the temporary substrate
Data Source
AI summary
A method for manufacturing silicon carbide wafers includes the following steps. A silicon carbide epitaxial layer is formed on a first silicon carbide substrate. An ion implantation process is used to form a thermal separation layer in the silicon carbide epitaxial layer. A temporary substrate is used to bond the silicon carbide epitaxial layer. Heating causes the thermal separation layer to decompose, and the silicon carbide epitaxial layer is divided into an upper silicon carbide epitaxial layer and a lower silicon carbide epitaxial layer. A chemical mechanical polishing process is performed on the upper silicon carbide epitaxial layer bonded to the temporary substrate.