Vacuum Processing Apparatus Gas Flow Control for Particle Contamination
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Solution Overview
Problem
During the transfer of a semiconductor wafer between a vacuum transfer chamber and a vacuum processing chamber, reaction by-products adhere to the inner surfaces and scatter as particles, contaminating the wafer due to sudden changes in gas flow rates and pressures when opening/closing the gate valve.
Innovation Solution
A vacuum processing apparatus with a control unit that manages the gas flow rates and pressures by supplying inert gas from the vacuum transfer chamber at a higher flow rate than the processing chamber and maintaining a lower pressure in the processing chamber, thereby suppressing the sudden flow of gas and reducing particle scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the flow rate of gas in the vacuum processing chamber is increased to suppress particle adhesion, then particle contamination is reduced, but particles may scatter into the vacuum transfer chamber
Solution Approach 1:
The patent applies different gas flow rates to different chambers: a first flow rate in the vacuum processing chamber and a second flow rate in the vacuum transfer chamber. This local differentiation allows the processing chamber to have sufficient gas flow to prevent particle adhesion while the transfer chamber maintains lower flow to avoid particle scattering, thus resolving the contradiction between preventing contamination and avoiding particle scattering.
Solution Approach 2:
The patent changes the gas flow rate parameter between chambers and over time. By setting the first flow rate in the processing chamber to be higher than the second flow rate in the transfer chamber during substrate transfer, the system dynamically adjusts parameters to prevent particle adhesion in the processing chamber while minimizing particle scattering into the transfer chamber.
2Object-affected harmful factors
If the pressure in the vacuum transfer chamber is increased to prevent atmosphere flow, then atmospheric contamination is reduced, but gas flow sudden changes cause particle peeling
Solution Approach 1:
The patent applies preliminary action by establishing appropriate gas flow rates and pressure differentials before substrate transfer begins. By pre-setting the first flow rate in the processing chamber and the second flow rate in the transfer chamber before opening the gate valve, the system prevents particle peeling caused by sudden gas flow changes while maintaining pressure differential to prevent atmospheric contamination.
Solution Approach 2:
The patent implements dynamic control of gas flow rates and pressures during the transfer process. The system dynamically adjusts the first and second flow rates to maintain appropriate pressure differential across the gate valve while preventing particle peeling, adapting the parameters throughout the transfer sequence rather than maintaining static conditions.
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 effectively reduces contamination of the substrate by minimizing the scattering of reaction by-products, ensuring cleaner wafer transfer and processing.
Implementation Method 1
a first gas supply unit configured to supply a gas in a shower pattern toward the mounting table
Implementation Method 2
a first gas exhaust port formed below the mounting table and configured to vacuum-evacuate the processing chamber
Implementation Method 3
a second gas supply unit configured to supply an inert gas into the transfer chamber
Implementation Method 4
a second gas exhaust port configured to vacuum-evacuate the transfer chamber
Data Source
AI summary
A vacuum processing apparatus for processing a substrate under a vacuum atmosphere includes a vacuum processing module, a vacuum transfer module, a gate valve and a control unit. The vacuum processing module includes a processing chamber, a mounting table and a first gas supply unit. The vacuum transfer module includes a transfer chamber airtightly connected to the processing chamber through the transfer port, a transfer unit and a second gas supply unit. The gate valve is configured to open and close the transfer port for the substrate. The control unit is configured to open the gate valve in a state where a flow rate of an inert gas supplied from the first gas supply unit is smaller than a flow rate of an inert gas supplied from the second gas supply unit and a pressure in the processing chamber is lower than a pressure in the transfer chamber.