Halogen Gas Chamber Purge Method for Stainless Steel Corrosion
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Solution Overview
Problem
In semiconductor device manufacturing, plasma etching processes using halogen-based gases like Cl2 result in metal contamination due to corrosion of stainless steel components when the chamber is exposed to the atmosphere, requiring lengthy purge cycles and dummy wafer processing to reduce contamination levels.
Innovation Solution
The method involves purging the chamber with oxygen gas or dry air before exposure to the atmosphere, either by using oxygen plasma or ion sputtering to reoxidize the passive film on stainless steel components, thereby suppressing corrosion and maintaining the protective film's integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the chamber is opened to the atmosphere for maintenance operation, then maintenance can be performed, but metal contamination occurs on the wafer due to corrosion of stainless steel components by halogen-based gas reacting with moisture in the air
Solution Approach 1:
The patent applies preliminary action by performing a purge operation with N2 gas or cycle purge before opening the chamber to the atmosphere. This preliminary purging removes or reduces the halogen-based gas from the chamber, preventing it from reacting with moisture in the air during subsequent maintenance operations, thereby avoiding metal contamination of wafers
Solution Approach 2:
The patent uses N2 gas as an intermediary substance to displace the halogen-based gas from the chamber before atmospheric exposure. The N2 gas acts as a mediator that prevents direct contact between the halogen-based gas and moisture in the air, eliminating the corrosion reaction that would otherwise contaminate wafers with metal particles
2Object-affected harmful factors
If N2 purge or cycle purge is performed until metal contamination becomes smaller than or equal to reference value, then metal contamination is reduced, but the purge requires a long period of time and processing of several tens to several hundreds of dummy wafers is required
Solution Approach 1:
The patent applies parameter changes by switching from using N2 gas to using O2 gas for the purge operation. This change in the chemical parameter of the purge gas fundamentally alters the interaction with halogen-based gas, enabling rapid removal or deactivation of corrosive halogen species without requiring lengthy purge cycles or dummy wafer processing, thereby dramatically reducing the time required while maintaining effective contamination control
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 significantly reduces the time required for purge cycles and dummy wafer processing, effectively preventing metal contamination by restoring the passive film and maintaining its protective properties against halogen-based gases.
Implementation Method 1
purging the chamber by supplying oxygen gas or dry air into the chamber
Implementation Method 2
processing an inside of the chamber by an oxygen plasma
Implementation Method 3
processing an inside of the chamber by an oxygen plasma
Implementation Method 4
The ion sputtering process may be performed by using argon ions obtained by generating a plasma of argon gas
Implementation Method 5
generating a plasma of argon gas
Data Source
AI summary
A processing apparatus performs a predetermined process on an object to be processed by supplying halogen-based gas into a chamber in which a vacuum is maintained, to which chamber a member having an oxide film formed on a surface thereof is connected, or which chamber has an oxide film formed on a surface thereof, wherein the predetermined processing is performed on the target object once or a plurality of times in the chamber. Later, oxygen gas or dry air is supplied to the chamber to purge the chamber, and then the chamber is opened and exposed to the atmosphere.