Edge Ring Bias and RF Control for Stable Plasma Sheath Position
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in maintaining the vertical position of the plasma sheath above the edge ring due to wear, which affects the processing efficiency and requires adjustments in direct-current voltage and radio frequency power levels.
Innovation Solution
The plasma processing apparatus includes a substrate support with a bias electrode and an edge ring connected through an impedance adjuster to adjust the negative bias level and an outer ring receiving radio frequency power to control plasma density distribution, allowing for adjustable sheath thickness and plasma distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the edge ring is worn and thickness is reduced, then the position of the upper end of plasma sheath above the edge ring becomes lower, but the processing uniformity deteriorates
Solution Approach 1:
The patent applies dynamics by making the edge ring height adjustable through a positioning mechanism. The edge ring can be moved vertically along the substrate support to compensate for wear, maintaining the optimal sheath position throughout the edge ring's service life. This dynamic adjustment resolves the contradiction between edge ring durability and processing uniformity.
Solution Approach 2:
The patent changes the physical parameter of edge ring position by introducing a positioning mechanism that allows vertical movement. By adjusting the position parameter of the edge ring relative to the substrate support, the system maintains consistent plasma sheath positioning despite edge ring thinning from wear over time.
2Manufacturing precision
If direct-current voltage is applied to the edge ring to adjust sheath position, then the sheath position can be controlled, but the device complexity increases
Solution Approach 1:
The patent replaces the electrical control system (direct-current voltage application) with a mechanical positioning mechanism. Instead of using complex voltage control to adjust sheath position, the system uses mechanical movement of the edge ring along the substrate support, simplifying the overall device complexity while achieving the same control objective.
3Manufacturing precision
If the position of plasma sheath above edge ring is not adjusted, then the device operation is simple, but the processing quality deteriorates
Solution Approach 1:
The patent implements self-service through an automatic positioning mechanism that adjusts the edge ring position based on detected sheath position or pre-set wear compensation parameters. The system automatically maintains optimal processing conditions without requiring manual intervention, thereby improving processing quality while keeping operations simple.
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 enables precise adjustment of the plasma sheath thickness and density distribution, enhancing the plasma processing efficiency and maintaining optimal conditions despite edge ring wear.
Implementation Method 1
a radio frequency power source configured to generate radio frequency power that is supplied to a radio frequency electrode to generate plasma
Implementation Method 2
The edge ring is electrically connected to the bias power source through an impedance adjuster that provides variable impedance between the bias electrode and the edge ring
Implementation Method 3
an impedance adjuster that provides variable impedance between the bias electrode and the edge ring
Implementation Method 4
The substrate is processed with chemical species such as ions and radicals from the plasma
Data Source
AI summary
The disclosed plasma processing apparatus includes a chamber, a substrate support, a radio frequency power source, and a bias power source. The radio frequency power source generates radio frequency power to generate plasma. The bias power source is connected to a bias electrode of the substrate support, and generates an electric bias. An edge ring mounted on the substrate support receives a part of the electric bias through an impedance adjuster or receives another electric bias. An outer ring extends outside the edge ring in a radial direction, and receives a part of the radio frequency power or other radio frequency power.