Plasma Showerhead Gas Tube Layout for Lower RF Power Loss
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Solution Overview
Problem
Existing plasma processing apparatuses face inefficiencies in electric power utilization due to the absorption of radio frequency waves by dielectric tubes used for gas supply, especially when these tubes are enlarged to ensure uniform gas distribution.
Innovation Solution
The apparatus incorporates a scattered arrangement of cylindrical dielectric tubes connected to the showerhead electrode, which penetrate the radio frequency waveguide, reducing the volume occupied by the dielectric tubes and minimizing power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dielectric tubes are enlarged to ensure uniform gas distribution, then gas supply uniformity is improved, but electric power loss increases due to absorption of radio frequency waves
Solution Approach 1:
The patent divides the single large dielectric tube into multiple smaller dielectric tubes arranged in an array. This segmentation allows the gas supply function to be distributed across multiple channels, maintaining uniform gas distribution while reducing the volume of each individual tube that absorbs radio frequency energy, thereby reducing overall power loss.
Solution Approach 2:
The patent transitions from a single large tube in one dimension to multiple smaller tubes arranged in a two-dimensional array. This dimensional change allows the system to maintain the total gas supply capacity and uniformity while reducing the cross-sectional area of individual tubes exposed to radio frequency waves, minimizing energy absorption.
2Manufacturing precision
If dielectric tubes are enlarged to ensure uniform gas distribution, then gas supply uniformity is improved, but thermal damage risk increases to the dielectric tubes
Solution Approach 1:
By segmenting the gas supply function across multiple smaller dielectric tubes, each tube has reduced exposure to radio frequency energy and associated heating. This segmentation distributes the thermal load, reducing the risk of thermal damage to any single tube while maintaining overall gas supply uniformity through the array configuration.
Solution Approach 2:
The patent applies local quality by making each dielectric tube in the array have optimized dimensions suitable for its local position and function. Each tube is sized appropriately to minimize thermal exposure while contributing to the overall uniform gas distribution, rather than using a single oversized tube that would be prone to thermal damage.
3Loss of energy
If scattered arrangement of dielectric tubes is used, then electric power loss is reduced, but device complexity increases
Solution Approach 1:
The array of scattered dielectric tubes serves multiple functions simultaneously: it provides gas supply channels, acts as a support structure for maintaining electrode positioning, and functions as a distributed radio frequency wave transmission medium. This multi-functionality reduces the need for separate components, offsetting the apparent complexity with functional integration.
Solution Approach 2:
The patent merges the gas supply function with the radio frequency waveguide structure by integrating the dielectric tubes directly into the waveguide assembly. This combination eliminates the need for separate gas supply lines and waveguide components, reducing overall device complexity despite the scattered tube arrangement.
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 suppresses electric power loss and reduces the risk of thermal damage to the dielectric tubes, while ensuring uniform gas supply and improved plasma processing efficiency.
Implementation Method 1
dielectric tubes formed of a dielectric material, wherein each of the dielectric tubes is connected to the electrode and penetrates a space between the electrode and the enlarged diameter portion to supply a gas to the electrode
Implementation Method 2
a waveguide part in order to supply radio frequency waves (VHF waves) to the introduction part
Implementation Method 3
The present disclosure relates to a plasma processing apparatus
Data Source
AI summary
A plasma processing apparatus includes: a coaxial tube that extends in a vertical direction and forms a portion of a radio frequency waveguide; a substrate support configured to support a substrate; an electrode including a gas flow path connected to a gas ejection port opened toward a space above the substrate support, wherein the electrode is provided above the substrate support and an inner conductor of the coaxial tube is connected to a center of the electrode; an enlarged diameter portion forming a part of the radio frequency waveguide together with the electrode and connected to an outer conductor of the coaxial tube; and dielectric tubes formed of a dielectric material, wherein each of the dielectric tubes is connected to the electrode and penetrates a space between the electrode and the enlarged diameter portion to supply a gas to the electrode, wherein the dielectric tubes is scatteredly provided.