Plasma Processing Apparatus Magnetic Field Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional capacitively coupled plasma processing apparatuses face challenges in controlling plasma density distribution, leading to undesirable non-uniformity where the center of the radial direction becomes a singular point, affecting process characteristics like etching rates.
Innovation Solution
A plasma processing apparatus is designed with a main magnet unit and an auxiliary magnet unit, where the main magnet unit includes annular electromagnetic coils around the central axis, and the auxiliary magnet unit forms a magnetic field that perpendicularly or obliquely crosses the central axis, combining to create an obliquely slanted magnetic field that suppresses electron localization and plasma density singularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high frequency power is supplied to the lower electrode at high frequency, then plasma generation efficiency is improved, but high frequency current gathers in the center of the lower electrode causing non-uniform plasma density distribution
Solution Approach 1:
The patent introduces magnetic field forming mechanisms (main magnet unit and auxiliary magnet unit) that create locally differentiated magnetic field strengths across the processing space. The main magnet unit generates a magnetic field that is stronger at the periphery than at the center, while the auxiliary magnet unit provides additional magnetic field components. This local differentiation of magnetic field properties prevents current gathering at the center and achieves uniform plasma density distribution across the substrate surface.
2Manufacturing precision
If a magnetic field forming mechanism is introduced to control plasma density distribution, then plasma uniformity is improved, but device complexity increases
Solution Approach 1:
The magnetic field forming mechanism is segmented into two independent units: a main magnet unit and an auxiliary magnet unit. The main magnet unit (with annular electromagnetic coils) provides the primary magnetic field for plasma uniformity control, while the auxiliary magnet unit (with multiple electromagnetic coils) provides supplementary magnetic field components. This segmentation allows each unit to be optimized independently and provides flexible control over plasma density distribution without requiring a completely complex magnetic field system.
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 controls plasma density distribution and etching rates across the substrate, preventing singular points and enhancing process uniformity and controllability.
Implementation Method 1
a main magnet unit including one or more annular main electromagnetic coils arranged around a central axis passing through the center of the lower electrode in a vertical direction from an upper portion or upper side of the processing container; and an auxiliary magnet unit configured to form a magnetic field that perpendicularly or obliquely crosses the central axis in the processing space
Implementation Method 2
a high frequency power source configured to apply a high frequency power between the upper electrode and the lower electrode; Then, plasma is generated between both electrodes due to high frequency discharge of the processing gas
Data Source
AI summary
Provided is a plasma processing apparatus that performs a processing on a processing target substrate by applying plasma of a processing gas on the processing target substrate. The plasma processing apparatus includes: a processing container configured to accommodate the processing target substrate; a lower electrode disposed in the processing container to mount the processing target substrate thereon; an upper electrode disposed in the processing container to face the lower electrode with a processing space being interposed therebetween; a high frequency power source configured to apply a high frequency power between the upper electrode and the lower electrode; a main magnet unit including one or more annular main electromagnetic coils arranged around a central axis; and an auxiliary magnet unit configured to form a magnetic field that perpendicularly or obliquely crosses the central axis in the processing space.