Dual Plasma Chamber Cleaning NF3 Gas Delivery
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Solution Overview
Problem
Substrate processing systems face inefficiencies in chamber cleaning processes, where film and reactant buildup on chamber surfaces requires prolonged cleaning cycles, disrupting substrate processing operations.
Innovation Solution
The method involves using nitrogen trifluoride (NF3) gas supplied to a remote plasma source and in-situ plasma generation within the processing chamber, with dual NF3 delivery paths to enhance etch rates and reduce cleaning time, employing RF power in specific ranges and varying pressures and temperatures to optimize the cleaning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional single plasma source cleaning is used, then the chamber can be cleaned, but the cleaning time is prolonged and productivity is reduced
Solution Approach 1:
The patent combines two plasma sources (remote plasma source and in-situ plasma source) into a single cleaning system. The remote plasma source provides plasma that travels through the chamber, while the in-situ plasma source generates plasma directly within the chamber. Both plasma sources operate simultaneously to clean the chamber surfaces, effectively merging their cleaning actions to reduce total cleaning time and improve productivity.
Solution Approach 2:
The cleaning function is segmented into two distinct plasma sources with different characteristics. The remote plasma source handles bulk plasma generation and transport, while the in-situ plasma source provides localized plasma generation at the chamber surfaces. This segmentation allows each source to optimize its contribution to the overall cleaning process, with the ability to independently control each source's operation.
2Productivity
If higher NF3 gas flow rate is used to increase etch rate, then cleaning speed improves, but plasma stability and process control deteriorate
Solution Approach 1:
The NF3 gas delivery system is segmented into two separate paths: one path supplies NF3 to the remote plasma source, and another path supplies NF3 directly to the chamber for in-situ plasma generation. This segmentation allows independent optimization of gas flow rates for each plasma source, enabling stable plasma operation at moderate NF3 flow rates while achieving high etch rates through the combined action of both plasma sources.
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 increases the etch rate from 1.4 μm/min to over 5 μm/min, reducing the chamber clean cycle time by over 40% while maintaining equivalent etch performance, as demonstrated by improved etch rate measurements and reduced cleaning periods.
Implementation Method 1
generating RPS plasma using the RPS; supplying the RPS plasma to the processing chamber
Implementation Method 2
cleaning the processing chamber during a cleaning period using both the RPS plasma and the in-situ plasma
Implementation Method 3
striking in-situ plasma in the processing chamber while the RPS plasma is supplied
Implementation Method 4
The in-situ plasma is generated using RF power in a range from 500 W to 3000 W
Implementation Method 5
supplying nitrogen trifluoride (NF3) gas to a remote plasma source (RPS); generating RPS plasma using the RPS
Data Source
AI summary
A method for cleaning a processing chamber of a substrate processing system includes supplying nitrogen trifluoride (NF3) gas to a remote plasma source (RPS); generating RPS plasma using the RPS; supplying the RPS plasma to the processing chamber; supplying NF3 gas as bypass gas to the processing chamber; striking in-situ plasma in the processing chamber while the RPS plasma is supplied; and cleaning the processing chamber during a cleaning period using both the RPS plasma and the in-situ plasma.