CVD Valve Sequencing for Debris Purging and Clean Product Transfer
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Solution Overview
Problem
Contamination of deposition products occurs when transferring them from the reactor to the collection chamber in chemical vapor deposition (CVD) systems due to debris entering the collection chamber.
Innovation Solution
A valve control sequence is implemented in the CVD system, utilizing a collection valve, purge valve, and bypass valve to purge debris away from the collection chamber, ensuring the deposition product is directed correctly and contaminants are minimized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the deposition product is transferred from the reactor to the collection chamber, then the CVD product can be produced, but debris may enter the collection chamber contaminating the deposition product
Solution Approach 1:
The system performs a purging action before transferring the deposition product to the collection chamber. The purging valve introduces purging gas to clear debris from the gas distribution system beforehand, preventing contamination of the deposition product during subsequent transfer operations
Solution Approach 2:
Purging gas is introduced as an intermediary substance to carry debris away from the collection chamber. The purging gas flows through the gas distribution system, capturing and transporting debris particles to safe locations away from the deposition product
2Object-affected harmful factors
If a purging gas flow is introduced into the gas distribution system to remove debris, then contamination is reduced, but reactor pressure stability may be affected
Solution Approach 1:
The purging operation is performed periodically at specific intervals rather than continuously. The controller activates the purging valve for predetermined time periods, introducing purging gas only when needed to remove debris, while maintaining normal operational pressure conditions during other periods
Solution Approach 2:
The system dynamically adjusts the flow rate and duration of purging gas based on operational conditions. The controller modulates the purging valve to optimize debris removal while minimizing impact on reactor pressure, changing parameters such as gas flow rate and purging duration to balance both objectives
3Object-generated harmful factors
If the bypass valve is opened to purge debris, then debris can be removed from the system, but the deposition product flow path may be affected
Solution Approach 1:
The gas distribution system is divided into separate flow paths: a main path for deposition product transfer and a bypass path for debris removal. The bypass valve controls the debris removal path independently, allowing simultaneous operation of both functions without interfering with each other
Solution Approach 2:
The system dynamically switches between different valve configurations depending on operational mode. During normal operation, the bypass valve remains closed to maintain efficient deposition product flow. During purging cycles, the bypass valve opens temporarily to redirect flow for debris removal, then closes to restore normal operation
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
The method reduces contamination, maintains reactor pressure stability, and ensures the quality and yield of the CVD product by effectively managing the flow of debris and deposition product through controlled valve positions.
Implementation Method 1
The purge valve being open can provide a flow of purging gas into the gas distribution system. The collection valve being open allows the purging gas to drive debris away from the collection valve
Implementation Method 2
The collection valve being open allows flow from the reactor to be directed through the collection valve to the collection chamber
Data Source
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AI summary
Disclosed is a method and a system for chemical vapor deposition. A collection valve between a reactor and a collection chamber and a purge valve between the collection valve and the collection chamber is open while a bypass valve for the collection chamber is open for purging debris from between the collection valve and the bypass valve through the bypass valve. Thereafter, the purge valve is closed and the collection valve open for directing the deposition product from the reactor to the collection chamber for treatment.