Resonant Structure for ECR Plasma Ionization
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Solution Overview
Problem
Achieving low-pressure plasma processing in semiconductor fabrication is challenging due to difficulties in maintaining uniformity and minimizing magnetic fields, which are necessary to confine electrons and ionize neutrals, while avoiding charging damage and processing non-uniformity.
Innovation Solution
A plasma processing system utilizing a resonant structure with distributed resonant elements and embedded magnets to generate electron cyclotron resonant plasma at low pressures, ensuring efficient energy coupling and uniform plasma distribution across the substrate, by synchronizing electromagnetic fields with electron cyclotron motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic fields are applied to confine electrons and ionize neutrals, then plasma generation is improved, but charging damage and processing non-uniformity increase
Solution Approach 1:
The patent divides the plasma processing chamber into multiple zones with independently controlled magnetic field strengths. By segmenting the magnetic field configuration, electrons can be confined in regions where ionization is needed while preventing excessive magnetic field exposure in regions where charging damage occurs, thus resolving the contradiction between plasma generation reliability and charging damage prevention
Solution Approach 2:
The patent implements spatially varying magnetic field characteristics where different regions of the processing chamber have optimized magnetic field strengths tailored to local requirements. This local quality approach allows strong magnetic fields for electron confinement in plasma generation zones while maintaining weak magnetic fields in substrate processing zones to minimize charging damage and non-uniformity
2Quantity of substance
If magnetic fields are strengthened to improve plasma density, then ionization efficiency increases, but processing uniformity deteriorates
Solution Approach 1:
The patent employs asymmetric magnetic field configuration where the magnetic field strength varies intentionally across different spatial locations. This asymmetric design creates high plasma density in specific regions through strong magnetic field confinement while maintaining processing uniformity in other regions through optimized field distribution, resolving the contradiction between plasma density and processing uniformity
3Productivity
If low pressure is applied to remove byproducts efficiently, then byproduct removal is improved, but plasma uniformity becomes harder to maintain
Solution Approach 1:
The patent implements dynamic control of magnetic field parameters that adapt to changing plasma conditions. By dynamically adjusting magnetic field strength and configuration in response to real-time plasma state measurements, the system maintains plasma uniformity even at low pressures where byproduct removal is enhanced, resolving the contradiction between productivity and manufacturing precision
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 high-density plasma generation at low pressures (<10 mTorr) with improved spatial uniformity and reduced magnetic field exposure, facilitating efficient etching and deposition processes while minimizing charge exchange and byproduct removal issues.
Implementation Method 1
The resonant elements generate localized regions of electromagnetic energy by amplifying the energy from the antenna when the energy is transmitted at a particular frequency, which causes the electromagnetic waves to oscillate at larger amplitude than the original or initial transmission from the antenna
Implementation Method 2
the electromagnetic field couples energy very efficiently into the electron cyclotron motion which heats the electrons. The nature of the coupling increases the heating efficiency of electrons while the magnetic field prevents the spatial loss of electrons especially of high energy electrons
Implementation Method 3
When this condition is met, the electromagnetic field couples energy very efficiently into the electron cyclotron motion which heats the electrons
Implementation Method 4
heating electrons to energies sufficient to sustain ionizing collisions. Heated electrons can have energy sufficient to sustain dissociative collisions
Implementation Method 5
Heated electrons can have energy sufficient to sustain dissociative collisions
Data Source
AI summary
Described herein is a technology related to a method for generating a high density plasma ionization on a plasma processing system. Particularly, the high density plasma ionization may include an electron cyclotron resonant (ECR) plasma that is utilized for semiconductor fabrication such as an etching of a substrate. The ECR plasma may be generated by a combination of electromagnetic fields from a resonant structure, radiated microwave energy from a radio frequency (RF) microwave source, and presence of a low-pressure plasma region (e.g., about 1 mTorr or less) on the plasma processing system.