Remote Plasma Source Cleaning End-Point Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Remote plasma source (RPS) cleaning in plasma processing devices lacks effective end-point detection methods, as there is no plasma in the chamber to produce optical or DC bias signals, complicating the determination of cleaning completion, especially for PECVD processes.
Innovation Solution
A method involving the creation of a plasma with radicals and ions in a remote source, where radicals enter the chamber while preventing ions, allowing for the detection of a DC bias on chamber components to determine the cleaning end-point without additional specialist detectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a remote plasma source is used for cleaning, then ion bombardment is reduced and chamber component wear is minimized, but end-point detection becomes impossible without additional specialist detectors
Solution Approach 1:
The chamber components themselves generate the DC bias signal that serves as the end-point detection indicator. The showerhead or chamber walls act as both the cleaning surface and the sensing element, eliminating the need for separate detection devices. The accumulated charge on these components during plasma exposure provides the measurement signal.
Solution Approach 2:
The DC bias voltage acts as an intermediary signal that translates the physical state of cleaning (contaminant removal) into a measurable electrical parameter. This intermediate electrical signal enables indirect detection of the cleaning endpoint without requiring direct optical or physical access to the plasma chamber interior.
2Measurement precision
If direct plasma cleaning is used, then end-point detection is enabled through optical or DC bias signals, but ion bombardment increases causing greater chamber component wear
Solution Approach 1:
The plasma generation function is separated from the cleaning function. The remote plasma source generates plasma in a separate location, which then delivers only the beneficial radical species to the chamber for cleaning, while the harmful ions remain confined to the remote source region. This spatial segmentation allows independent optimization of both cleaning effectiveness and component protection.
Solution Approach 2:
The harmful ions are extracted or removed from the plasma mixture before it contacts the chamber components. The remote plasma source design allows ions to be confined to the plasma generation region while only neutral radicals are allowed to enter the chamber, effectively separating the useful cleaning agents from the damaging species.
3Productivity
If remote plasma source cleaning is used, then chamber maintenance frequency is reduced, but end-point detection requires additional specialist detectors
Solution Approach 1:
The chamber structure itself provides the detection function through accumulated DC bias signals. No external or additional detection equipment is needed - the chamber components serve dual purposes as both cleaning targets and sensing elements, maintaining high productivity while avoiding increased device complexity.
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
Enables reliable and direct end-point detection within the process chamber using a measurable DC bias signal, reducing maintenance needs and ensuring effective cleaning of PECVD devices without requiring optical or infrared detectors.
Implementation Method 1
creating a plasma within a remote plasma source which is separated from the chamber, the plasma comprising radicals and ions
Implementation Method 2
detecting a DC bias developed on a component of the chamber during cleaning; and using the detected DC bias to determine an end-point of the cleaning
Data Source
AI summary
A method of cleaning a chamber of a plasma processing device with radicals includes creating a plasma within a remote plasma source which is separated from the chamber, the plasma including radicals and ions, cleaning the chamber by allowing radicals to enter the chamber from the remote plasma source while preventing the majority of the ions created in the remote plasma source from entering the chamber, detecting a DC bias developed on a component of the chamber during cleaning; and using the detected DC bias to determine an end-point of the cleaning and, on determination of the end-point, to stop the cleaning.