Plasma Processing Apparatus Edge Ring Sheath Control
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Solution Overview
Problem
The existing plasma processing apparatuses face challenges in maintaining a uniform sheath top location between the substrate and the edge ring, leading to differences in plasma processing conditions due to variations in edge ring thickness.
Innovation Solution
A plasma processing apparatus with high-frequency and bias power supplies that generate electric bias energy with specific waveform cycles to adjust the power levels and voltages applied to the substrate and edge ring, reducing the difference in sheath top locations by synchronizing the power levels within the cycle, thereby controlling the sheath thickness and plasma density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If negative DC voltage is applied to the edge ring to thicken the sheath, then the difference in sheath top location is resolved, but the plasma processing uniformity deteriorates due to excessive sheath thickness variation
Solution Approach 1:
The patent applies periodic RF voltage to the edge ring instead of continuous DC voltage. The RF voltage alternates between positive and negative cycles, creating periodic sheath thickness variations that average out to a more uniform effective sheath thickness, thereby resolving the contradiction between achieving sheath top location uniformity and maintaining plasma processing uniformity
Solution Approach 2:
The patent changes the voltage parameter from DC to RF, fundamentally altering the electrical characteristics applied to the edge ring. This parameter change transforms the sheath formation mechanism from static to dynamic, enabling simultaneous achievement of sheath top location uniformity and plasma processing uniformity through controlled voltage oscillation
2Productivity
If the edge ring thickness is decreased to improve plasma processing, then the sheath top location difference increases, but this leads to non-uniform plasma conditions
Solution Approach 1:
By applying periodic RF voltage to the edge ring, the patent dynamically adjusts the sheath thickness during each RF cycle. This periodic action compensates for the reduced physical thickness of the edge ring, maintaining consistent sheath top location and plasma conditions even as the edge ring thickness decreases to improve processing efficiency
3Manufacturing precision
If different power levels are applied to substrate and edge ring to control sheath thickness, then sheath top location uniformity improves, but the device complexity increases due to additional power supply control
Solution Approach 1:
The patent makes the edge ring serve multiple functions: it acts as both a mechanical support structure and an RF electrode for plasma generation. By integrating the RF power supply function into the existing edge ring structure, the patent achieves sheath top location uniformity without adding separate control systems, thereby improving precision while avoiding increased device complexity
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 reduces the difference in sheath top locations between the substrate and the edge ring, maintaining consistent plasma processing conditions and plasma density across varying edge ring thicknesses, enhancing the overall plasma processing efficiency.
Implementation Method 1
at least one high-frequency power supply configured to generate first high-frequency power and second high-frequency power
Implementation Method 2
at least one bias power supply configured to generate first electric bias energy and second electric bias energy
Implementation Method 3
A plasma processing apparatus is used for plasma processing for a substrate
Data Source
AI summary
There is a plasma processing apparatus comprising: a chamber; a substrate support configured to support a substrate and an edge ring; high-frequency power supply configured to generate first high-frequency power via the substrate and second high-frequency power via the edge ring; and bias power supply configured to generate first electric bias energy supplied to the substrate and second electric bias energy supplied to the edge ring, wherein the first electric bias energy and the second electric bias energy have a waveform repeatedly at a cycle, the cycle includes a first period in which voltage of each of the first and second electric bias energies has a positive level with respect to an average value of the voltage within the cycle, and a second period in which the voltage of each of the first and second electric bias energies has a negative level with respect to the average value.