Dual-Fed Microwave Plasma Source for Uniform PE-ALD Discharge
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Solution Overview
Problem
Existing microwave plasma sources for substrate processing face challenges with discharge stability and uniformity, particularly in generating plasmas with high charge and radical densities while maintaining low ion energies.
Innovation Solution
The proposed solution involves a plasma source assembly with a powered electrode enclosed by a dielectric and a ground electrode, where two microwave generators operate at different frequencies to provide microwave power to both ends of the powered electrode, enhancing plasma stability and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If microwave fields are used to generate plasma with high charge and radical densities, then plasma density is improved, but discharge stability and uniformity deteriorate
Solution Approach 1:
The patent divides the microwave power input into multiple independent sources (first and second microwave generators) positioned at opposite ends of the powered electrode. This segmentation allows each generator to independently control plasma generation at its respective end, preventing the instability that occurs when a single high-power source creates excessive localized plasma density. The segmented approach maintains high overall plasma density while improving discharge stability through distributed power input.
Solution Approach 2:
The patent applies different microwave power levels and frequencies at different locations along the powered electrode. Each end of the electrode can have customized power input characteristics tailored to local plasma generation needs. This local quality approach ensures uniform plasma distribution across the entire electrode length, preventing the non-uniformity that arises from centralized power input while maintaining high plasma density where needed.
2Quantity of substance
If microwave fields are used to generate plasma with high charge and radical densities, then plasma density is improved, but spatial uniformity deteriorates
Solution Approach 1:
By segmenting the microwave power input into multiple independent sources at opposite ends of the powered electrode, the patent creates a distributed plasma generation system. This segmentation ensures that plasma is generated uniformly along the entire length of the electrode, preventing localized plasma concentration that would cause spatial non-uniformity. The segmented approach maintains high plasma density while achieving uniform plasma distribution across the processing area.
Solution Approach 2:
The patent transitions from a single-point or single-region plasma generation approach to a distributed multi-point plasma generation system by positioning microwave generators at opposite ends of the powered electrode. This dimensional expansion of the power input configuration ensures that plasma is generated uniformly across the entire electrode length, achieving spatial uniformity while maintaining high plasma density throughout the processing volume.
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 achieves stable and uniform plasma generation with high charge and radical densities and low ion energies, improving the efficiency and effectiveness of substrate processing in semiconductor manufacturing.
Implementation Method 1
Using microwave fields at frequencies in GHz range instead, in certain resonant or wave-propagation electromagnetic modes, plasma of very high charge and radical densities and with very low ion energies can be generated
Implementation Method 2
in certain resonant or wave-propagation electromagnetic modes, plasma of very high charge and radical densities
Implementation Method 3
A dielectric is on a second side of the powered electrode. The dielectric and ground electrode enclose the powered electrode
Data Source
AI summary
Plasma source assemblies, gas distribution assemblies including the plasma source assembly and methods of generating a plasma are described. The plasma source assemblies include a powered electrode with a ground electrode adjacent a first side and a dielectric adjacent a second side. A first microwave generator is electrically coupled to the first end of the powered electrode through a first feed and a second microwave generator is electrically coupled to the second end of the powered electrode through a second feed.