Plasma Processing Apparatus Azimuthal Density Control
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Solution Overview
Problem
Conventional capacitively coupled plasma processing apparatuses face challenges in achieving uniform plasma density distribution and process characteristics due to asymmetry in the apparatus configuration, leading to non-uniformity in the azimuthal direction, which complicates manufacturing and increases costs.
Innovation Solution
The introduction of a plasma processing apparatus with a high-frequency electrode configuration that includes a first conductor and a second conductor, where the first conductor is capacitively coupled to the rear surface of the high-frequency electrode, and the second conductor is connected to a grounding member, allowing for the adjustment of plasma distribution by varying the position or capacitance of these conductors to balance the plasma density and sheath electric field intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high-frequency electrode is used to generate plasma in a capacitively coupled plasma processing apparatus, then plasma generation is achieved, but non-uniform plasma density distribution occurs in the azimuthal direction due to apparatus configuration asymmetry
Solution Approach 1:
The high-frequency electrode is divided into multiple independent electrode segments (first electrode segment, second electrode segment, third electrode segment, fourth electrode segment) arranged around the processing chamber. Each segment can be independently controlled to compensate for asymmetry in the apparatus configuration, thereby achieving uniform plasma density distribution without requiring complex overall electrode structures.
Solution Approach 2:
Different electrode segments are assigned different high-frequency power levels to create localized plasma density adjustments. The power supply unit independently controls each electrode segment, allowing local optimization of plasma density in specific azimuthal regions to counteract configuration-induced non-uniformity.
2Manufacturing precision
If conventional electrode configurations are used, then apparatus structure is simple, but plasma distribution uniformity deteriorates due to asymmetry in the azimuthal direction
Solution Approach 1:
The system dynamically adjusts the high-frequency power supplied to each electrode segment based on real-time plasma distribution requirements. The power supply unit can independently vary power levels to each segment, enabling adaptive compensation for asymmetry and maintaining uniform plasma distribution throughout the processing chamber.
Solution Approach 2:
The invention changes the power distribution parameter across different electrode segments rather than using uniform power supply. By varying the power level to each electrode segment independently, the system achieves uniform plasma density distribution while maintaining a relatively simple overall apparatus structure.
3Ease of manufacture
If the high-frequency electrode configuration is simplified, then manufacturing cost decreases, but the degree of freedom in controlling plasma density distribution is reduced
Solution Approach 1:
The electrode is segmented into multiple independent sections, each capable of independent power control. This segmentation provides high degrees of freedom for plasma density control while keeping each individual segment structurally simple and easy to manufacture.
Solution Approach 2:
Each electrode segment serves multiple functions: it generates plasma, allows independent power control for uniformity adjustment, and can be configured to compensate for various asymmetry patterns. This multi-functionality provides high control flexibility without requiring complex specialized structures.
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 effectively cancels out unbalances in plasma distribution and process characteristics, improving uniformity and the degree of freedom in controlling plasma density, thereby enhancing the performance and manufacturing efficiency of the plasma processing apparatus.
Implementation Method 1
a high frequency power of a predetermined frequency is applied to the upper electrode or the lower electrode via a matching unit. Electrons are accelerated by a high frequency electric field generated by this high frequency power and these accelerated electrons collide with molecules/atoms of a processing gas, resulting in dissociation/ionization therebetween and, thus, the processing gas is excited into plasma
Implementation Method 2
a first conductor which has first and second surfaces facing opposite directions to each other and is electrically connected with the rear surface of the high frequency electrode with respect to the first high frequency power
Implementation Method 3
a high frequency power of a predetermined frequency is applied to the upper electrode or the lower electrode via a matching unit. Electrons are accelerated by a high frequency electric field generated by this high frequency power
Data Source
AI summary
A plasma processing apparatus includes at least one asymmetry member that causes a non-uniformity of plasma density around the high frequency electrode; and a plasma density distribution controller that is arranged depending on arrangement of the at least one asymmetry member to suppress the non-uniformity of plasma density around the high frequency electrode in the azimuthal direction. The plasma density distribution controller includes a first conductor which has first and second surfaces facing opposite directions to each other and is electrically connected with the rear surface of the high frequency electrode with respect to the first high frequency power; and a second conductor which includes a first connecting portion(s) electrically connected with a portion of the second surface of the first conductor and a second connecting portion electrically connected with a conductive grounding member electrically grounded around the high frequency electrode with respect to the first high frequency power.