Plasma Stage Cleaning by Impedance-Controlled Edge Plasma
Find Innovative SolutionsGenerate Solutions
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
1Reliability
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 locally enhanced at the outer peripheral portions of the stage where deposits accumulate, while maintaining lower density in central areas. This localized plasma concentration enables targeted cleaning of deposit-prone regions without subjecting the entire stage to high-energy plasma that would cause damage.
Solution Approach 2:
The patent changes the impedance parameter of the stage to control plasma distribution. By adjusting the impedance characteristics of the stage structure, the plasma density distribution is modified to concentrate plasma at outer peripheral portions. This parameter change allows the system to achieve effective cleaning in deposit accumulation zones while controlling overall plasma energy to prevent stage damage.
2Productivity
If plasma density is increased to improve cleaning efficiency, then deposit removal speed is improved, but stage damage increases
Solution Approach 1:
The patent implements local quality by creating spatial variation in plasma density. High plasma density is concentrated specifically at outer peripheral portions where deposits accumulate, providing intensive cleaning action where needed. The central regions maintain lower plasma density, reducing unnecessary exposure to high-energy plasma and minimizing stage damage while preserving cleaning efficiency in critical areas.
3Stability of the object's composition
If uniform plasma distribution is maintained, then process stability is improved, but deposit removal effectiveness deteriorates
Solution Approach 1:
The patent deliberately introduces asymmetry into the plasma distribution to match the asymmetric deposit accumulation pattern. Instead of maintaining uniform plasma distribution, the system creates higher plasma density at outer peripheral portions where deposits preferentially accumulate. This asymmetric plasma distribution effectively targets the asymmetric deposit problem while maintaining overall process stability through controlled impedance management.
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 special 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.