SiC Substrate Vapor Etching for Work-Affected Layer Removal
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Solution Overview
Problem
Conventional methods for removing the work-affected layer from silicon carbide (SiC) substrates, such as mechanical processing, are inefficient and can introduce processing damage, while existing etching techniques using abrasive grains or Si vapor pressure etching have limitations in effectively reducing or removing the work-affected layer without compromising the substrate quality.
Innovation Solution
A method and device that utilize a main container capable of generating vapor pressure of Si and C elements, with a temperature gradient to etch the SiC substrate, allowing for the reduction or removal of the work-affected layer without mechanical processing, using a polycrystalline SiC main container and a high melting point container with a Si vapor supply source to maintain vapor pressure and control etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical processing (slicing, grinding, polishing) is used to manufacture SiC substrate, then the substrate can be formed from ingot, but a work-affected layer with scratches and crystal distortion is introduced on the surface
Solution Approach 1:
The patent replaces mechanical processing methods with a thermal field-based etching method. By applying a temperature gradient to the SiC substrate in a controlled atmosphere, the work-affected layer is selectively removed through thermal etching rather than mechanical abrasion, thereby eliminating scratches and crystal distortion while maintaining ease of manufacture
Solution Approach 2:
The patent utilizes changes in temperature parameters to achieve selective etching. By controlling the temperature gradient across the substrate surface and adjusting heating parameters, the work-affected layer is removed at specific temperature zones while preserving the underlying crystal structure, thus improving surface quality without compromising manufacturing efficiency
2Manufacturing precision
If abrasive grains such as diamond are used for surface processing to remove work-affected layer, then the layer can be removed, but processing damage may be introduced and yield is lowered
Solution Approach 1:
The patent replaces mechanical abrasion with thermal field etching. By using controlled thermal energy to remove the work-affected layer, the method avoids the mechanical stress and micro-fractures caused by abrasive grains, thereby maintaining high substrate yield while achieving effective layer removal
Solution Approach 2:
The patent exploits phase transition phenomena in the thermal etching process. By heating the substrate to specific temperature ranges, material transformation occurs that enables selective removal of the work-affected layer through vaporization or phase change mechanisms, avoiding mechanical damage and preserving substrate integrity
3Object-affected harmful factors
If Si vapor pressure etching is used to etch SiC wafer, then etching can be performed without abrasive grains, but the effectiveness in removing work-affected layer is limited
Solution Approach 1:
The patent enhances Si vapor pressure etching by introducing and controlling temperature gradient parameters. By establishing a specific temperature distribution across the substrate and adjusting heating parameters, the etching efficiency is significantly improved, enabling complete removal of the work-affected layer while maintaining the advantage of avoiding abrasive grains
Solution Approach 2:
The patent introduces dynamic control of the thermal field through time-varying temperature gradients. By adjusting the heating parameters and temperature distribution during the etching process, the method achieves optimal etching rates and selectivity, overcoming the limitations of static Si vapor pressure etching while maintaining its non-abrasive nature
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 approach effectively reduces or removes the work-affected layer from SiC substrates, improving substrate quality and yield by using a vapor pressure environment and temperature gradient to drive the etching process, thereby minimizing processing damage and enhancing the manufacturing process efficiency.
Implementation Method 1
a main container capable of accommodating a SiC substrate and configured to generate vapor pressure of a gaseous species containing Si element and a gaseous species containing C element in an internal space by heating
Implementation Method 2
a heating furnace that accommodates the main container, generates vapor pressure of a gaseous species containing Si element in an internal space, and performs heating in a manner to form a temperature gradient
Implementation Method 3
an etching process of etching a SiC substrate by accommodating the SiC substrate inside a main container that generates vapor pressure of a gaseous species containing Si element and a gaseous species containing C element
Data Source
AI summary
A device for manufacturing a SiC substrate, in which the occurrence of a work-affected layer is reduced, or from which a work-affected layer is removed, comprises: a main container which can accommodate a SiC substrate and which generates, by heating, a vapor pressure of a vapor-phase species including elemental Si and a vapor-phase species including elemental C in an internal space; and a heating furnace for accommodating the main container, generating a vapor pressure of the vapor-phase species including elemental Si in the internal space, and heating so that a temperature gradient is formed; the main container having an etching space formed by causing a portion of the main container disposed on the low-temperature side of the temperature gradient and the SiC substrate to face each other in a state in which the SiC substrate is disposed on the high-temperature side of the temperature gradient.