Dipole Ring Magnet Electron Filtering in Plasma Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma etching processes face inefficiencies due to high average electron energies, which impede ion formation and result in reduced dissociative attachment at the substrate, leading to non-uniform plasma distribution and potential substrate damage from electromagnetic waves.
Innovation Solution
A Dipole Ring Magnet (DRM) assembly is used to create a cross-B magnetic field in the processing chamber, directing high energy electrons away from the substrate while allowing lower energy electrons to reach the substrate, thereby achieving uniform low average electron energy flux and reducing electron density irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plasma etching processes are used, then plasma is formed to enable material removal, but high average electron energies impede ion formation and reduce dissociative attachment at the substrate
Solution Approach 1:
A dipole ring magnet assembly is introduced as an intermediary component between the microwave antenna and substrate. The magnet creates a magnetic field that interacts with electrons in the plasma, causing low-energy electrons to be guided along magnetic field lines to the substrate while high-energy electrons are excluded, thereby enabling selective electron energy control at the substrate surface
Solution Approach 2:
The patent changes the magnetic field configuration parameter by using a dipole ring magnet arrangement with specific pole orientations. This creates a unique magnetic field topology that selectively transmits low-energy electrons while blocking high-energy electrons, fundamentally altering the electron energy distribution at the substrate without changing the plasma source parameters
2Object-affected harmful factors
If high energy electrons are allowed to reach the substrate, then plasma density is maintained, but substrate damage occurs from unmitigated electromagnetic waves and high energy electron impact
Solution Approach 1:
The dipole ring magnet serves as a protective intermediary that filters electrons based on their energy levels. The magnetic field configuration creates a selective barrier that allows beneficial low-energy electrons to reach the substrate while blocking harmful high-energy electrons, thereby protecting the substrate without compromising plasma density
Solution Approach 2:
The patent converts the potentially harmful high-energy electron population into a beneficial filtering mechanism. By introducing the magnetic field, high-energy electrons are deflected and excluded, while the same magnetic field structure guides and concentrates low-energy electrons onto the substrate, turning the electron energy distribution challenge into a selective delivery mechanism
3Manufacturing precision
If uniform plasma distribution is desired, then plasma sources are optimized, but electron density irregularities and non-uniformity persist near the substrate
Solution Approach 1:
The dipole ring magnet assembly acts as a uniformizing intermediary by creating a magnetic field that redistributes electron flux across the substrate surface. The magnetic field lines guide electrons in a controlled manner, smoothing out local variations and achieving uniform electron energy and density distribution across the entire substrate area
Solution Approach 2:
The patent changes the spatial distribution parameter of electron flux by introducing the magnetic field. The dipole configuration with alternating poles creates a magnetic field topology that naturally distributes electron flow uniformly across the substrate, transforming the non-uniform electron density profile into a uniform distribution without modifying the plasma source geometry
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
The DRM assembly effectively filters higher energy electrons, enhancing ion formation and plasma uniformity near the substrate, improving etch performance and reducing the risk of substrate damage.
Implementation Method 1
a dipole magnetic field is imposed across a process space between the plasma source and the supported substrate, perpendicular to the direction of electron motion, with sufficient strength, height, and position to cause electrons having energies below an acceptable maximum level to divert from the substrate
Implementation Method 2
The DRM assembly effectively filters higher energy electrons, enhancing ion formation and plasma uniformity near the substrate
Implementation Method 3
plasma is formed when a portion of the gas species is ionized by collisions with energetic electrons. The gas may be ionized by direct current, radio frequency, microwave energy
Data Source
AI summary
A method and apparatus is provided for obtaining a low average electron energy flux onto a substrate in a processing chamber. A processing chamber includes a substrate support therein for chemical processing. An energy source induced plasma, and ion propelling means, directs energetic plasma electrons toward the substrate support. A dipole ring magnet field is applied perpendicular to the direction of ion travel, to effectively prevent electrons above an acceptable maximum energy level from reaching the substrate holder. Rotation of the dipole magnetic field reduces electron non-uniformities.