SiC Film-Forming Chamber Cleaning to Cut Residual Defects
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Solution Overview
Problem
Conventional methods for cleaning SiC film-forming devices, such as wiping or hydrogen gas supply, are inefficient and can introduce impurities and defects into the SiC film, and the use of ClF3 gas alone during cleaning can lead to high defect rates and impurity incorporation in the film.
Innovation Solution
A cleaning method involving the use of a fluorine-based cleaning gas (ClF3) to remove reaction products followed by air introduction to remove residual impurities and defects, combined with a hydrogen annealing process to set the carrier concentration and reduce impurities, allowing for effective and rapid cleaning of the film-forming device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wiping or polishing methods are used to remove reaction products, then cleaning is achieved, but workability is poor and device downtime becomes longer due to cooling time requirements
Solution Approach 1:
The patent replaces mechanical wiping or polishing methods with a chemical cleaning method using hydrogen gas flow. Instead of physically removing reaction products through contact with wipes or polishing tools, the invention uses hydrogen gas to chemically react with and remove the reaction products (particularly silane deposits) from the processing container walls and components, thereby eliminating the need for mechanical contact and subsequent cooling periods.
Solution Approach 2:
The patent changes the cleaning approach from mechanical to chemical by introducing hydrogen gas at specific flow rates and temperatures. By controlling the hydrogen gas flow rate and temperature parameters, the cleaning process becomes more efficient and faster, reducing device downtime while maintaining effective removal of reaction products.
2Reliability
If ClF3 gas is used to remove reaction products, then cleaning is achieved, but many defects occur in the SiC film formed after cleaning due to remaining impurities
Solution Approach 1:
The patent extracts or removes the harmful ClF3 gas from the cleaning process and replaces it with hydrogen gas. This substitution eliminates the problem of ClF3-related impurities and defects in the subsequently formed SiC film, while still achieving effective removal of reaction products through hydrogen's chemical reaction capabilities.
Solution Approach 2:
The patent uses hydrogen gas as a temporary, consumable cleaning agent that reacts with and removes reaction products, then is exhausted from the system. This disposable approach with hydrogen gas avoids the persistence of harmful residues that ClF3 would leave behind, ensuring cleaner film formation.
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 significantly reduces impurities and defects in the SiC film, enabling the formation of high-quality films with controlled impurity concentrations and reduced defect rates, while minimizing downtime and ensuring safety during the cleaning process.
Implementation Method 1
a reaction product removal process of removing a reaction product, which is formed during the film formation and attached to portions other than the substrate to be processed, by supplying a fluorine-based cleaning gas into the processing container after the film formation
Implementation Method 2
a residue removal process of removing a substance, which remains after the reaction product removal process and serves as an unnecessary impurity or causes a defect during a subsequent film formation, by supplying air into the processing container
Implementation Method 3
combined with a hydrogen annealing process to set the carrier concentration and reduce impurities
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A cleaning method of cleaning a film-forming device, which includes a processing container having a substrate holder provided in the processing container so as to hold a SiC substrate, and which supplies a source gas to the processing container, an interior of which is depressurized, and heats the SiC substrate so as to perform a film formation on the SiC substrate, includes: a reaction product removal process of removing a reaction product, which is formed during the film formation and attached to portions other than the SiC substrate, by supplying a ClF3 gas into the processing container after the film formation; and a residue removal process of removing a substance, which remains after the reaction product removal process and serves as an unnecessary impurity or causes a defect during a subsequent film formation, by supplying air into the processing container.