Plasma Treatment Device with Annular Insulating Ring for Density Control
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Solution Overview
Problem
Existing plasma treatment devices using high-frequency waves in the VHF or UHF band face challenges in achieving uniform plasma density distribution due to surface wave interference, making it difficult to flexibly control plasma density according to process conditions.
Innovation Solution
A plasma treatment device with a circular upper electrode and an annular insulating ring, utilizing a high-frequency power supply and a bias power supply to control the attenuation coefficient of surface waves, allowing for flexible control of plasma density distribution by adjusting the bias voltage and wave energy distribution radially across the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-frequency waves in the VHF or UHF band are applied to generate plasma, then plasma density can be increased, but surface wave interference causes non-uniform plasma density distribution
Solution Approach 1:
The patent applies local quality by making different parts of the lower electrode have different thicknesses. Specifically, the electrode thickness is increased toward the outer edge compared to the center region. This creates localized variations in electromagnetic wave propagation characteristics, allowing surface waves to attenuate more uniformly across the electrode surface and reducing the non-uniform plasma density distribution caused by wave interference.
Solution Approach 2:
The patent changes the physical parameter of electrode thickness to control plasma density uniformity. By varying the thickness parameter of the lower electrode across different radial positions, the electromagnetic wave attenuation characteristics are modified, which in turn controls the uniformity of plasma density generation while maintaining high plasma density overall.
2Manufacturing precision
If the lower electrode thickness is increased toward the outer edge to improve plasma density uniformity, then uniformity is improved, but the electrode shape becomes fixed and inflexible
Solution Approach 1:
The patent applies dynamics by making the lower electrode thickness adjustable rather than fixed. The electrode includes a thickness adjustment mechanism that allows the thickness to be changed dynamically according to different processing requirements. This enables flexible control of plasma density distribution while maintaining uniformity when needed, adapting to various process conditions.
Solution Approach 2:
The patent segments the lower electrode into multiple adjustable thickness zones. Rather than a single fixed thickness profile, the electrode is divided into regions with different adjustable thicknesses, allowing independent control of plasma density characteristics in different areas. This segmentation provides flexibility to optimize plasma distribution for different process 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
Enables flexible control of plasma density distribution, improving uniformity and reducing plasma generation interference, thereby enhancing processing efficiency and reducing damage to workpieces during semiconductor manufacturing.
Implementation Method 1
high-frequency waves in the VHF band or the UHF band are applied to an electrode, electromagnetic waves generated by the high-frequency waves propagate as surface waves on the surface of the electrode
Implementation Method 2
a plasma treatment is performed on a workpiece by exposing the workpiece to plasma
Implementation Method 3
a bias power supply configured to apply a second high-frequency wave or a direct current (DC) bias voltage to the upper electrode
Data Source
AI summary
A plasma treatment device includes: a chamber body including a chamber defined therein; a gas supply part that supplies a processing gas into the chamber; a stage disposed within the chamber; an upper electrode having a circular surface that faces the stage; a conductor connected to the upper electrode; a high-frequency power supply that generates a first high-frequency wave; a bias power supply that applies a second high-frequency wave or a direct current bias voltage to the upper electrode; an annular insulating ring extending along an outer edge of the circular surface; a waveguide through which electromagnetic waves generated around the conductor based on the first high-frequency wave propagate, the waveguide being connected to the annular insulating ring outside the upper electrode; and a controller that controls the second high-frequency wave or the direct current bias voltage to be applied to the upper electrode.