SiC Surface Planarization via Ion Implantation and Wet Etching
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Solution Overview
Problem
The high surface roughness of SiC substrates post-mechanical separation poses challenges for manufacturing electronic devices, as conventional polishing methods are costly and complex due to the hardness of SiC, which is comparable to diamond.
Innovation Solution
A method involving the formation of a sacrificial material with a specific density on the roughened SiC surface, followed by ion implantation to create an amorphous region, and subsequent wet etching to planarize the surface, reducing stress and costs compared to mechanical and chemical-mechanical polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mechanical and chemical-mechanical polishing is used to planarize the roughened SiC surface, then the surface quality is improved, but the process complexity and cost increase due to the very high hardness of SiC
Solution Approach 1:
The patent replaces the conventional mechanical polishing system with an ion implantation system followed by wet chemical etching. Instead of using mechanical abrasion to remove material, the process uses ion implantation to create an amorphous region that is then selectively removed by wet etching, thereby eliminating the need for complex mechanical and chemical-mechanical polishing steps while achieving the desired surface planarity
Solution Approach 2:
The patent changes the physical and chemical state of the SiC surface by implanting ions to transform the crystalline structure into an amorphous region. This parameter change (from crystalline to amorphous) enables selective removal by wet etching, providing a different mechanism for material removal that bypasses the hardness-related complexities of mechanical polishing
2Manufacturing precision
If conventional mechanical and chemical-mechanical polishing is used to planarize the roughened SiC surface, then the surface quality is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive mechanical polishing equipment and processes with ion implantation and wet etching. This substitution eliminates the need for multiple polishing stages, diamond abrasives, and complex process control systems, thereby reducing capital equipment costs and operational expenses while maintaining surface quality
Solution Approach 2:
The patent uses a sacrificial amorphous region created by ion implantation that is intentionally designed to be removed by wet etching. This disposable intermediate structure enables surface planarization without requiring expensive polishing equipment, as the amorphous layer serves its purpose and is then eliminated to reveal the planarized crystalline surface
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 process effectively reduces surface roughness, providing a cost-effective and less complex method for achieving a planar surface suitable for electronic device fabrication, with the ability to repeat the process for further planarization if needed.
Implementation Method 1
forming a sacrificial material on the roughened surface of the SiC substrate
Implementation Method 2
implanting ions through the sacrificial material and into the roughened surface of the SiC substrate to form an amorphous region in the SiC substrate
Implementation Method 3
removing the sacrificial material and the amorphous region of the SiC substrate by wet etching
Data Source
AI summary
A method of planarizing a roughened surface of a SiC substrate includes: forming a sacrificial material on the roughened surface of the SiC substrate, the sacrificial material having a density between 35% and 120% of the density of the SiC substrate; implanting ions through the sacrificial material and into the roughened surface of the SiC substrate to form an amorphous region in the SiC substrate; and removing the sacrificial material and the amorphous region of the SiC substrate by wet etching.