Halogen Acidic Gas Molecular Weight Control for Film Formation Apparatus
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Solution Overview
Problem
Conventional cleaning methods for film formation apparatuses in semiconductor processes face instability and yield reduction due to by-product film deposition on reaction tube surfaces, leading to stress and particle generation, which deteriorate components and decrease product yield.
Innovation Solution
A film formation apparatus and method that control the average molecular weight of halogen acidic gases within a specific range (20-23) to form a quasi-mono-molecular atmosphere, preventing gas liquefaction and clustering, and ensuring stable supply and effective etching of by-product films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cleaning gas is supplied to remove by-product films from the reaction tube, then the reaction tube is cleaned, but gas liquefaction and clustering occur causing unstable cleaning process
Solution Approach 1:
The patent controls the average molecular weight of the cleaning gas mixture as a key parameter to prevent liquefaction. By adjusting the composition ratio of HF and other gases, the average molecular weight is maintained within a specific range (20-23), which corresponds to maintaining the gas in a quasi-mono-molecular state and preventing phase transition to liquid.
Solution Approach 2:
The patent uses a composite gas mixture consisting of HF and other gases (such as N2, Ar, or organic compounds) in specific ratios. This composite approach allows control of the average molecular weight while maintaining effective cleaning capability, preventing liquefaction that would occur with pure HF at certain conditions.
2Productivity
If by-product films are deposited on the reaction tube interior, then film formation process continues, but stress and particle generation occur deteriorating components
Solution Approach 1:
The patent implements periodic cleaning cycles interspersed with film formation processes. After a certain number of film formation runs, the system automatically performs a cleaning cycle using the controlled gas mixture to remove accumulated by-product films, preventing stress buildup and particle generation while maintaining high productivity.
3Reliability
If conventional cleaning methods are used, then by-product films are removed, but cleaning cannot be stably performed and yield decreases
Solution Approach 1:
The patent incorporates monitoring of cleaning effectiveness and adjusts the gas composition and flow parameters based on observed results. By measuring cleaning outcomes and feeding this information back to adjust the average molecular weight control parameters, the system achieves stable, repeatable cleaning that maintains high product yield.
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 stabilizes the cleaning process, reduces particle generation, and prevents component damage, thereby maintaining high product yield and extending apparatus lifespan.
Implementation Method 1
etching and removing a by-product film deposited on an inner surface of the reaction chamber, by use of the cleaning gas thus supplied
Implementation Method 2
a cleaning gas, such as a mixture gas of fluorine and a halogen-containing acidic gas, is supplied into the reaction tube. The by-product films deposited on the inner surface of the reaction tube are thereby dry-etched and removed by the cleaning gas
Implementation Method 3
the interior of the reaction tube (reaction chamber) of a heat-processing apparatus is heated by a heater at a predetermined load temperature
Implementation Method 4
the film formation gas causes a thermal reaction and thereby produces reaction products
Implementation Method 5
gas inside the reaction tube is exhausted through an exhaust port, so that the pressure inside the reaction tube is reduced to a predetermined pressure
Implementation Method 6
the pressure inside the reaction tube is reduced to a predetermined pressure
Implementation Method 7
The reaction products are deposited on the surface of each semiconductor wafer, and form a thin film on the surface of the semiconductor wafer
Implementation Method 8
a process, such as CVD (Chemical Vapor Deposition), is performed to form a thin film
Data Source
AI summary
A method for using a film formation apparatus for a semiconductor process forms a first atmosphere inside an upstream gas passage between a gas supply source of a halogen acidic gas and a flow rate controller. The first atmosphere is set for the halogen acidic gas to have an average molecular weight of 20 or more and 23 or less. Further, the using method supplies the halogen acidic gas from the gas supply source through the upstream gas passage having the first atmosphere thus formed and the flow rate controller, thereby supplying a cleaning gas containing the halogen acidic gas into a reaction chamber of the film formation apparatus. A by-product film deposited on an inner surface of the reaction chamber is etched and removed by use of the cleaning gas thus supplied.