Remote Plasma Source Asymmetric Annular Volume
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Solution Overview
Problem
Open loop RF source configurations in plasma processing systems face challenges in achieving plasma uniformity, leading to non-uniform plasma density distribution and subsequent processing inconsistencies in plasma processing chambers.
Innovation Solution
The design incorporates a plasma source with a magnetically permeable core element and coils generating magnetic fields aligned with the core's axis, creating an annular plasma-generating volume that is symmetrical about multiple perpendicular axes, with a first region closer to the core having a width significantly greater than its depth, ensuring uniform plasma distribution across the processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an open loop RF source configuration with an annular plasma chamber surrounding a linear magnetically permeable core is used, then plasma generation efficiency is improved by creating plasma 360 degrees around the core, but plasma uniformity deteriorates with density peaks skewed in the horizontal direction
Solution Approach 1:
The plasma chamber cross-section is designed with asymmetric dimensions where the width (first dimension) is at least three times greater than the depth (second dimension). This asymmetric geometry compensates for the inherent plasma skewing tendency in open loop configurations, redistributing the plasma density more uniformly across the horizontal direction while maintaining the 360-degree plasma generation capability around the magnetically permeable core.
2Ease of operation
If minor adjustments are made to the RPS hardware configuration such as coil position relative to the plasma chamber, then ease of operation is improved, but plasma uniformity deteriorates with dramatic shifts in plasma density distribution
Solution Approach 1:
The system incorporates adjustable coil positions and orientations that can be dynamically configured to optimize plasma uniformity. The asymmetric plasma chamber geometry provides a stable baseline configuration that is relatively insensitive to minor positional adjustments, while still allowing for deliberate reconfiguration when process optimization is required. This dynamic adjustability enables operators to restore uniformity after adjustments without causing dramatic shifts.
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 configuration enhances plasma uniformity and processing consistency by allowing a broader processing window without increasing hardware or processing costs, ensuring uniform plasma supply to the substrate, thereby improving the quality of electronic device fabrication processes.
Implementation Method 1
one or more coils disposed around respective one or more first portions of the core element
Implementation Method 2
magnetically permeable core element and coils generating magnetic fields aligned with the core's axis
Implementation Method 3
creating an annular plasma-generating volume that is symmetrical about multiple perpendicular axes
Implementation Method 4
plasma-generating volume disposed around a second portion of the core element
Data Source
AI summary
A plasma source is provided including a core element extending from a first end to a second end along a first axis. The plasma source further includes one or more coils disposed around respective one or more first portions of the core element. The plasma source further includes a plasma block having one or more interior walls at least partially enclosing an annular plasma-generating volume that is disposed around a second portion of the core element. The annular plasma-generating volume includes a first region that is symmetrical about a plurality of perpendicular axes that are perpendicular to a first point positioned on the first axis, the first region having a width in a direction parallel to the first axis and a depth in a direction perpendicular from the first axis. The first region has a width that is at least three times greater than the depth of the first region.