SiC Semiconductor Component Surface Purification via Oxidation-Stripping
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Solution Overview
Problem
Current semiconductor processing components, particularly those formed by chemical vapor deposition (CVD) of silicon carbide (SiC), face challenges with high impurity levels at the surface that are significantly higher than in the bulk, leading to contamination issues during wafer processing, especially with metals like iron and chromium, which are not adequately addressed by existing methods.
Innovation Solution
A method involving the removal of a target portion of the outer surface of the CVD-SiC component through oxidation-stripping or etching, followed by heat treatment to diffuse impurities into a gettering layer, thereby reducing the surface impurity level to be no greater than 80% of the bulk impurity level, creating a denuded skin portion with enhanced purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CVD-SiC outer surface portion is used as-is, then bulk impurity level is controlled, but skin impurity level becomes significantly higher than bulk level causing contamination
Solution Approach 1:
The patent applies preliminary action by performing oxidation and etching treatments on the CVD-SiC outer surface portion before the component is used in semiconductor processing. This pre-treatment removes the impurity-enriched skin layer that would otherwise contaminate wafers during processing, while preserving the low impurity bulk material.
Solution Approach 2:
The patent extracts the harmful skin impurity layer from the CVD-SiC outer surface portion through oxidation and etching processes. The oxidation step converts surface impurities into removable compounds, and the etching step physically removes the oxidized skin layer, separating the contaminated surface from the clean bulk material.
2Object-generated harmful factors
If oxidation-stripping or etching is applied to remove surface impurities, then skin impurity level is reduced, but component structure is modified
Solution Approach 1:
The patent applies parameter changes by controlling the oxidation temperature, time, and atmospheric composition to selectively modify only the skin portion of the outer surface. The etching parameters are similarly controlled to remove a precise thickness range (1 nm to 100 nm), preserving the bulk structure while eliminating surface impurities.
3Object-generated harmful factors
If heat treatment is applied to diffuse impurities, then skin impurity level is reduced to ≤80% of bulk level, but processing time and temperature increase
Solution Approach 1:
The patent implements continuous useful action by combining oxidation, etching, and heat treatment in a sequential integrated process. The oxidation and etching steps prepare the surface to enhance the effectiveness of the subsequent heat treatment, allowing impurity diffusion to occur more efficiently and achieve the desired skin impurity level reduction with optimized energy input.
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 surface impurity levels to match or be lower than bulk levels, significantly improving the purity of semiconductor processing components, thereby reducing contamination and enhancing the quality of semiconductor wafer processing.
Implementation Method 1
The outer surface portion is formed by chemical vapor deposition (CVD) of SiC
Implementation Method 2
heat treating is carried out to diffuse impurities from the surface of the outer surface portion
Data Source
AI summary
A semiconductor processing component has an outer surface portion comprised of silicon carbide, the outer surface portion having a skin impurity level and a bulk impurity level. The skin impurity level is average impurity level from 0 nm to 100 nm of depth into the outer surface portion, the bulk impurity level is measured at a depth of at least 3 microns into the outer surface portion, and the skin impurity level is not greater than 80% of the bulk impurity level.