Edge Ring Self-Bias Feedback for Plasma Chamber Cleaning Control
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Solution Overview
Problem
The existing plasma processing apparatuses face challenges in effectively controlling the cleaning of the inner chamber surface due to the formation of deposits, which affect substrate processing, and existing methods do not adequately utilize real-time feedback from self-bias potential changes for cleaning determination.
Innovation Solution
A method that involves measuring the self-bias potential of an edge ring during plasma generation and controlling the cleaning process based on this measurement, using a DC voltage applied to the edge ring, and determining the necessity and completion of cleaning by comparing the self-bias potential with a threshold value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cleaning is performed frequently to remove deposits from the inner chamber surface, then the processing quality is improved, but the loss of time and reduced productivity occur
Solution Approach 1:
The system measures the self-bias potential of the edge ring, which changes in response to deposit formation on the inner chamber surface. This real-time feedback allows the cleaning process to be triggered only when actually needed, rather than following a fixed schedule. The self-bias potential serves as an indicator of the chamber's cleaning state, enabling intelligent decision-making about when cleaning should occur.
Solution Approach 2:
The edge ring's self-bias potential automatically reflects the deposition state of the inner chamber surface without requiring direct measurement of the chamber walls. The system uses this self-generated signal to determine cleaning needs, allowing the chamber to essentially report its own cleaning status through the edge ring's electrical properties.
2Productivity
If cleaning is delayed to maintain productivity, then the productivity is improved, but the processing quality deteriorates due to deposit accumulation
Solution Approach 1:
By continuously monitoring the self-bias potential of the edge ring, the system maintains real-time awareness of deposit accumulation on the inner chamber surface. This feedback mechanism ensures that cleaning is initiated at the optimal moment - just when deposits begin to affect processing quality - thereby maintaining high processing quality while minimizing unnecessary cleaning interruptions and preserving productivity.
3Measurement precision
If real-time monitoring of inner chamber surface condition is implemented, then the cleaning control precision is improved, but the device complexity increases
Solution Approach 1:
The edge ring acts as an intermediary element that translates the condition of the inner chamber surface into a measurable electrical signal (self-bias potential). Instead of directly measuring the chamber surface, the system measures the edge ring's potential, which responds to deposit formation. This indirect measurement approach achieves high cleaning control precision while avoiding the complexity of direct chamber surface sensing.
Solution Approach 2:
The edge ring serves multiple functions: it defines the processing region, applies DC voltage during plasma generation, and simultaneously acts as a sensor for detecting chamber cleaning status through its self-bias potential. This multi-functionality eliminates the need for separate sensing components, reducing device complexity while maintaining high measurement precision for cleaning control.
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 allows for precise and responsive cleaning control, ensuring the inner surface of the chamber is maintained in an optimal state by utilizing the self-bias potential as a feedback mechanism, thereby improving substrate processing outcomes.
Implementation Method 1
processing a substrate using plasma generated in the chamber
Implementation Method 2
measuring a self-bias potential of the edge ring during the plasma generation
Data Source
AI summary
A method for controlling cleaning of an inner surface of a chamber of a plasma processing apparatus is provided. The method comprises; processing a substrate using plasma generated in the chamber, the substrate being disposed on a substrate support in the chamber and in a region surrounded by an edge ring placed on the substrate support and to which a DC voltage is applied during the plasma generation; measuring a self-bias potential of the edge ring during the plasma generation in said processing the substrate; and controlling the cleaning of the inner surface of the chamber in response to the self-bias potential.