Remote Plasma Cleaning Gas Distribution for Chamber Efficiency
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Solution Overview
Problem
Current methods for cleaning process chambers, such as those used in chemical vapor deposition (CVD) and plasma enhanced chemical vapor deposition (PECVD), face inefficiencies due to premature recombination of atomic fluorine radicals and poor gas circulation, leading to low cleaning efficiency, especially in chambers with large volumes and intricate geometries.
Innovation Solution
A method and apparatus that utilize a remote plasma source to supply cleaning plasma from both the top and bottom of the process chamber, with a gas distribution system and conduits that ensure even gas flow and prevent radical recombination, enhancing cleaning efficiency by creating a turbulent flow under the substrate support assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cleaning plasma is supplied from a remote plasma source through complex transport paths, then cleaning plasma can be provided to the deposition chamber, but atomic fluorine radicals recombine into molecular gases prematurely, reducing etching rate
Solution Approach 1:
The gas distribution system is divided into multiple separate conduits: a first gas conduit for supplying cleaning gas to the showerhead and a second gas conduit for supplying cleaning gas directly to the region below the substrate support assembly. This segmentation allows atomic fluorine radicals to reach different chamber regions through shorter, separate paths, reducing premature recombination
Solution Approach 2:
The invention introduces gas supply from a new dimension by adding a second gas conduit that supplies cleaning gas from below the substrate support assembly, in addition to the conventional top-down supply through the showerhead. This multi-directional approach shortens transport paths and maintains higher atomic fluorine radical concentrations
2Productivity
If the chamber pumping port is positioned close to the shower head in large volume chambers, then chamber evacuation is efficient, but gas circulation under the substrate support assembly is poor, decreasing cleaning efficiency
Solution Approach 1:
The gas distribution system is segmented into multiple independent pathways: one through the showerhead for upper chamber regions and another through the second gas conduit for the region below the substrate support assembly. This ensures uniform gas circulation throughout the entire chamber volume
Solution Approach 2:
Gas supply is extended to a new spatial dimension by introducing the second gas conduit that delivers cleaning gas from below the substrate support assembly, creating turbulent flow in previously poorly circulated regions and achieving uniform cleaning across the entire chamber
3Reliability
If cleaning gas is flowed through long complex paths from the remote plasma source, then cleaning plasma can reach the deposition chamber, but cleaning efficiency decreases due to radical recombination
Solution Approach 1:
The single long transport path from the remote plasma source is segmented into multiple shorter pathways through separate gas conduits. The first gas conduit supplies the showerhead while the second gas conduit supplies the region below the substrate support assembly, both receiving cleaning gas through shorter, more efficient paths that maintain higher atomic fluorine radical concentrations
Solution Approach 2:
The invention adds a new gas supply dimension by introducing the second gas conduit from below the substrate support assembly, creating multiple short transport paths instead of relying on a single long path, thereby improving both reliability of plasma delivery and productivity through maintained radical concentration
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 improves cleaning efficiency by reducing radical recombination and ensuring thorough gas circulation, resulting in a higher etching rate and more effective removal of deposition residues from the chamber.
Implementation Method 1
The RPS provides the cleaning plasma, usually formed from a fluorine-based cleaning gas
Implementation Method 2
precursor dissociation efficiency of cleaning gases
Implementation Method 3
enhancing cleaning efficiency by creating a turbulent flow under the substrate support assembly
Implementation Method 4
To obtain a higher etching rate during cleaning, the cleaning plasma is usually supplied in an active form comprised of atomic fluorine radicals
Data Source
AI summary
A method and apparatus for cleaning a process chamber are provided. In one embodiment, a process chamber is provided that includes a remote plasma source and a process chamber having at least two processing regions. Each processing region includes a substrate support assembly disposed in the processing region, a gas distribution system configured to provide gas into the processing region above the substrate support assembly, and a gas passage configured to provide gas into the processing region below the substrate support assembly. A first gas conduit is configured to flow a cleaning agent from the remote plasma source through the gas distribution assembly in each processing region while a second gas conduit is configured to divert a portion of the cleaning agent from the first gas conduit to the gas passage of each processing region.