Mesh Electrode Plasma Supply for Lower Sheath Voltage Control
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Solution Overview
Problem
Existing plasma processing apparatuses with remote plasma sources face challenges in reducing the influence of the remote plasma source on plasma, leading to potential damage to electrodes and leakage of particles into the outer region.
Innovation Solution
The plasma processing apparatus includes a plasma supply part with an upper and lower electrode, a gas supply part, and a voltage adjusting part. The voltage adjusting part lowers the sheath voltage of the sheath region formed on the lower electrode part, reducing damage and particle leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a remote plasma source is used to supply radicals to the processing chamber, then plasma processing capability is improved, but the sheath voltage on the lower electrode part increases causing electrode damage and particle leakage
Solution Approach 1:
A mesh electrode is introduced as an intermediary component between the lower electrode part and the plasma. The mesh electrode has a potential slightly higher than the lower electrode part, creating a gentle potential gradient that reduces ion bombardment energy while still allowing radical supply. This intermediary structure prevents direct high-energy ion impact on the lower electrode part, thereby reducing electrode damage and particle leakage.
2Productivity
If the plasma supply part generates plasma with high energy ions, then radical supply efficiency is improved, but particle leakage into the outer region increases
Solution Approach 1:
The mesh electrode is designed with specific local properties: it has a potential that is locally adjusted to be slightly higher than the lower electrode part, creating a localized gentle potential gradient in the sheath region. This local quality adjustment allows high-energy plasma generation for efficient radical supply while simultaneously creating a protective zone that prevents particle leakage into the outer region.
3Power
If the sheath voltage is maintained at high level for effective plasma generation, then plasma generation efficiency is improved, but damage to the lower electrode part increases
Solution Approach 1:
The electrode structure is segmented into multiple components: the lower electrode part, the mesh electrode, and the upper electrode. This segmentation allows the sheath voltage to be maintained at high levels for effective plasma generation in the bulk plasma region, while the mesh electrode acts as a buffer that protects the lower electrode part from direct high-voltage damage. The potential gradient is distributed across the segmented structure rather than concentrated on a single electrode.
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
The solution effectively reduces the sheath voltage, minimizing damage to the lower electrode part and suppressing particle leakage, thereby enhancing the reliability and efficiency of the plasma processing apparatus.
Implementation Method 1
The plasma supply part and the voltage adjusting part may be configured to lower a sheath voltage of a sheath region formed on the lower electrode part during plasma generation in the plasma supply part
Implementation Method 2
The upper electrode may be electrically connected to the RF power supply and to which an RF voltage from the RF power supply may be applied
Data Source
AI summary
A plasma processing apparatus comprises a plasma supply part including an upper electrode being electrically connected to a RF power supply and to which an RF voltage from the RF power supply is applied, and a lower electrode part being disposed to face the upper electrode, a gas supply part configured to supply to the plasma supply part a processing gas, and a voltage adjusting part used for adjusting a voltage of the upper electrode. The lower electrode part includes an electrode plate having a mesh structure and configured to allow communication between an inner region and an outer region of the plasma supply part provided by the lower electrode part. The plasma supply part and the voltage adjusting part are configured to lower a sheath voltage of a sheath region formed on the lower electrode part during plasma generation in the plasma supply part.