Stage Cleaning Gap Control for Edge-Focused Plasma Removal
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Solution Overview
Problem
In plasma processing apparatuses, deposits such as CF-based polymers tend to accumulate more on the outer peripheral portions of the stage due to uneven plasma distribution, leading to incomplete cleaning and potential damage when extended cleaning times are used to remove these deposits.
Innovation Solution
A method involving a lifting mechanism to separate the substrate from the stage, setting a specific separation distance that lowers the combined impedance around the outer peripheral portion, allowing for concentrated plasma generation and efficient removal of deposits on the outer peripheral areas while minimizing damage to the stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma processing is extended to remove deposits on outer peripheral portions, then cleaning completeness is improved, but stage damage increases
Solution Approach 1:
The patent applies local quality by creating non-uniform plasma distribution through specific impedance control. The plasma density is made higher at the outer peripheral portions where deposits accumulate, while maintaining lower density at central portions. This localized plasma concentration enables targeted cleaning of deposit-prone areas without subjecting the entire stage to high-energy plasma that would cause damage.
Solution Approach 2:
The patent changes electrical parameters (impedance values) to control plasma distribution. By adjusting the impedance of plasma-generating electrodes relative to the stage, the system creates optimal plasma density patterns. The impedance ratio between electrodes and stage is specifically controlled to concentrate plasma at outer peripheral portions for effective deposit removal while limiting overall plasma energy to prevent stage damage.
2Device complexity
If uniform plasma distribution is used, then processing simplicity is maintained, but deposit removal efficiency on outer peripheral portions deteriorates
Solution Approach 1:
The patent implements local quality by designing plasma-generating electrodes with spatially varying impedance characteristics. The impedance is configured to be lower at outer peripheral portions and higher at central portions, creating localized plasma concentration. This non-uniform plasma distribution directly addresses the deposit accumulation pattern, improving removal efficiency at problem areas without requiring complex mechanical or procedural modifications.
Solution Approach 2:
The patent replaces mechanical or procedural complexity with electrical parameter control. Instead of using complex electrode geometries, mechanical adjustments, or multi-step processing sequences to achieve non-uniform plasma distribution, the system simply adjusts electrical impedance parameters. This substitution maintains processing simplicity while dramatically improving deposit removal efficiency at outer peripheral portions.
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 enables effective removal of deposits on the outer peripheral stage areas with reduced damage, utilizing uneven plasma distribution to enhance cleaning efficiency without requiring specialized plasma-generating electrodes.
Implementation Method 1
removing a deposit deposited on the stage with plasma generated by supplying a high-frequency power from the high-frequency power supply to the stage
Data Source
AI summary
A method of cleaning a stage in a plasma processing apparatus including the stage on which a substrate is placed, a lifting mechanism configured to raise and lower the substrate with respect to the stage, and a high-frequency power supply connected to the stage, includes: separating the stage and the substrate from each other using the lifting mechanism; and after the separating the stage and the substrate from each other, removing a deposit deposited on the stage with plasma generated by supplying a high-frequency power from the high-frequency power supply to the stage. In the separating the stage and the substrate from each other, a separation distance between the stage and the substrate is set such that a combined impedance formed around an outer peripheral portion of the stage is lower than a combined impedance formed immediately above a central portion of the stage.