Chromium Oxide Film Contamination Prevention in Substrate Processing
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Solution Overview
Problem
Metal contamination occurs when chromium oxide films on metal components react with chlorine during substrate processing, leading to corrosion and contamination of reaction gases, which deteriorates the quality and reliability of the substrate processing process.
Innovation Solution
A method involving the generation of chromium chloride (III) hexahydrate by reacting hydrochloric acid with chromium oxide, followed by its evaporation to remove chromium from the film surface, and subsequent coverage with a metal compound from the metal chloride gas to prevent chromium diffusion and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chromium oxide film is used to cover metal component surface, then corrosion resistance is improved, but metal contamination occurs when chromium reacts with chlorine
Solution Approach 1:
The patent applies preliminary action by performing a pre-treatment process before substrate processing. Hydrochloric acid is supplied to the metal component to react with chromium oxide and form chromium chloride (III) hexahydrate, which is then evaporated to remove chromium from the surface. This preliminary removal of chromium prevents contamination during subsequent chlorine-based processing while maintaining corrosion resistance through the形成的 metal compound coating.
Solution Approach 2:
The patent extracts the harmful chromium element from the inactive film surface through chemical reaction and evaporation. By converting chromium oxide to chromium chloride (III) hexahydrate and then evaporating it, the chromium is removed from the surface where it could cause contamination, while the metal component retains its protective coating structure.
2Object-generated harmful factors
If inactive film is removed to prevent chromium contamination, then metal contamination is reduced, but corrosion protection is compromised
Solution Approach 1:
The patent uses an intermediary substance - a metal compound containing the same metal as the metal chloride gas - to replace chromium oxide on the surface. This intermediary coating serves dual purposes: it prevents chromium contamination by blocking chromium release while maintaining corrosion protection by providing a protective metal compound layer on the metal component surface.
Solution Approach 2:
The patent changes the chemical composition parameter of the surface coating from chromium oxide to a metal compound (such as aluminum oxide or other metal oxides/hydroxides). This parameter change maintains the protective function of the coating while eliminating the harmful chromium element that causes contamination during chlorine-based processing.
3Productivity
If metal chloride gas is passed through chromium oxide film, then substrate processing is performed, but chromium diffuses into reaction gas
Solution Approach 1:
The patent performs preliminary removal of chromium from the metal component surface before passing metal chloride gas through the system. By pre-reacting with hydrochloric acid and evaporating chromium chloride (III) hexahydrate, the chromium source is eliminated, ensuring high-purity reaction gas during substrate processing without compromising processing efficiency.
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
Effectively prevents chromium contamination by removing chromium from the inactive film and replacing it with a metal compound, ensuring high-purity and high-quality substrate processing by preventing chromium from mixing with reaction gases.
Implementation Method 1
supplying a hydrochloric acid to the inactive film covering the surface of the metal component, allowing the nitric acid to react with a chromium oxide to generate a chromium nitrate
Implementation Method 2
evaporating the generated chromium nitrate to remove the chromium from the inactive film
Implementation Method 3
covering a surface of the inactive film with a compound containing a metal contained in the metal chloride gas
Data Source
AI summary
There is provided a metal contamination prevention method performed by passing a metal chloride gas through a metal component having a surface covered with an inactive film formed of a chromium oxide, the method including: generating a chromium chloride (III) hexahydrate by supplying a hydrochloric acid to the inactive film covering the surface of the metal component and allowing the chromium oxide to react with the hydrochloric acid; removing a chromium from the inactive film by evaporating the chromium chloride (III) hexahydrate; and covering a surface of the inactive film with a compound containing a metal contained in the metal chloride gas.