Movable Ring Gap Tuning for Plasma Stage Edge Deposit Removal
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Solution Overview
Problem
In plasma processing apparatuses, deposits accumulate on the outer periphery of the stage, inner periphery of the ring member, and lower surface of the edge ring, making it difficult to remove them without damaging the stage, as the narrow region between these components restricts plasma entry and prolonging cleaning time can lead to stage damage.
Innovation Solution
A plasma processing apparatus with a stage and elevating mechanism that separates the ring member from the second placement surface, generating plasma with a higher density between the outer edge of the first placement surface and the inner edge of the ring member's lower surface, allowing for targeted removal of deposits while minimizing damage to the stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma is supplied continuously to remove deposits, then deposit removal effectiveness is improved, but stage damage increases
Solution Approach 1:
The ring member is made movable relative to the stage through an elevating mechanism, allowing dynamic adjustment of the gap between them. This enables the plasma density to be dynamically controlled - higher when the gap is smaller for effective deposit removal, and lower when the gap is larger to protect the stage from damage.
Solution Approach 2:
The invention creates localized high-density plasma in the narrow region between the stage and ring member by controlling their relative position. This concentrates the plasma effect where it is most needed (at the edges) while reducing overall plasma exposure to the stage, achieving selective cleaning with minimized damage.
2Productivity
If the gap between stage and ring member is reduced to increase plasma density, then deposit removal speed is improved, but stage damage risk increases
Solution Approach 1:
The elevating mechanism enables dynamic control of the gap distance, allowing the system to operate in different modes: close gap for high-speed deposit removal, and larger gap for stage protection. This dynamic adjustment resolves the contradiction between removal speed and damage risk.
Solution Approach 2:
The cleaning process can be performed in periodic cycles where the ring member is alternately positioned close to the stage for deposit removal and then moved away for stage protection. This periodic action allows intensive cleaning followed by recovery periods.
3Reliability
If cleaning time is prolonged to remove all deposits, then cleaning completeness is improved, but stage lifespan is reduced
Solution Approach 1:
By concentrating plasma density in the narrow edge region through precise positioning of the ring member, the invention achieves effective local cleaning of deposits where they accumulate most heavily. This localized intensive cleaning achieves sufficient cleaning completeness without requiring prolonged overall cleaning time that would damage the stage.
Solution Approach 2:
The ring member is positioned to create the high-density plasma region before the cleaning process begins, preparing the plasma distribution pattern that enables effective deposit removal while inherently limiting stage exposure to damaging plasma levels throughout the cleaning duration.
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
Effectively removes deposits from the outer periphery of the stage, inner periphery of the ring member, and lower surface of the edge ring in a short time while protecting the stage from excessive plasma exposure, thus extending its lifespan.
Implementation Method 1
supplying radio-frequency power from the radio-frequency power source to the stage to generate plasma
Data Source
AI summary
A plasma processing apparatus includes: a stage having first and second placement surfaces; an elevating mechanism for raising and lowering a ring member on the second placement surface with respect to the second placement surface; a radio-frequency power source; and a controller for executing a cleaning process including an operation of separating the second placement surface and the ring member from each other by the elevating mechanism; and an operation of removing deposits accumulated on the stage and the ring member by supplying radio-frequency power from the radio-frequency power source to the stage to generate plasma. In the separation operation, a distance between the second placement surface and the ring member is set such that a density of plasma generated in a region between an outer edge of the first placement surface and a lower surface of the ring member is higher than that of plasma generated in other regions.