Movable Conductive Control Ring for Local Plasma Pressure Stabilization
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Solution Overview
Problem
Existing plasma confinement systems face challenges in maintaining stable pressure control within the confinement region, leading to plasma sheath collapse and unconfined plasma formation due to fluctuations in pressure volume/level, which affects semiconductor processing quality.
Innovation Solution
A local pressure control and plasma confinement arrangement using a movable conductive control ring positioned next to the peripheral ring, allowing for adjustment of slot size to maintain pressure within the confinement region without affecting the outside chamber volume, combined with an automatic feedback system to monitor and adjust pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the pressure volume/level is increased by tightening the vacuum valve, then the pressure control is improved, but the plasma sheath collapses and plasma confinement is lost
Solution Approach 1:
The chamber is divided into two distinct pressure zones: a confinement region (within the peripheral ring) and an outside chamber volume. The peripheral ring with slots acts as a segmented barrier that confines plasma to the confinement region while allowing neutral gas to pass through. This segmentation enables independent pressure control in each zone, allowing pressure increase without plasma sheath collapse affecting the entire chamber.
Solution Approach 2:
The invention implements local pressure control by creating a specific pressure environment within the confinement region that is different from the outside chamber volume. The peripheral ring structure provides localized plasma confinement with slots that have specific geometric properties (cross-sectional area less than two times the plasma sheath) to maintain plasma confinement locally while allowing gas flow. This local quality differentiation resolves the contradiction by maintaining plasma confinement properties locally even when overall chamber pressure increases.
2Quantity of substance
If the slot cross-sectional area is increased to allow neutral gas flow, then the gas exhaust is improved, but the plasma sheath can no longer confine plasma within the confinement region
Solution Approach 1:
The peripheral ring is designed with movable or adjustable slots that can dynamically adapt their opening size. This dynamic structure allows the slots to maintain an opening size that is large enough to exhaust neutral gas species effectively while remaining small enough (cross-sectional area less than two times the plasma sheath) to prevent plasma from traversing through. The dynamic adjustment capability resolves the contradiction between gas flow and plasma confinement requirements.
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 solution effectively stabilizes plasma within the confinement region, maintaining consistent process parameters and preventing plasma leakage, thereby enhancing semiconductor device quality and reducing the risk of chamber component damage from unconfined plasma.
Implementation Method 1
the plasma may be confined to a limited chamber volume, such as the region within a peripheral ring
Implementation Method 2
A local pressure control and plasma confinement arrangement using a movable conductive control ring positioned next to the peripheral ring, allowing for adjustment of slot size to maintain pressure within the confinement region
Implementation Method 3
Each slot has a geometry that is configured to be large enough to allow the neutral gas species to exit the confinement region and flow toward the turbo pump by traversing through the slots. Generally, to be effective in confining the plasma within the confinement area, each slot tends to have a cross-sectional of less than two times the plasma sheath.
Implementation Method 4
To exhaust the neutral gas species from the confinement region (the volume within the peripheral ring), the peripheral ring may include a plurality of slots
Data Source
AI summary
An arrangement for performing pressure control within a processing chamber substrate processing is provided. The arrangement includes a peripheral ring configured at least for surrounding a confined chamber volume that is configured for sustaining a plasma for etching the substrate during substrate processing. The peripheral ring includes a plurality of slots that is configured at least for exhausting processed byproduct gas from the confined chamber volume during substrate processing. The arrangement also includes a conductive control ring that is positioned next to the peripheral ring and is configured to include plurality of slots. The pressure control is achieved by moving the conductive control ring relative to the peripheral ring such that a first slot on the peripheral ring and a second slot on the conductive control ring are offset with respect to one another in a range of zero offset to full offset.