Substrate Support Electrode Segmentation for Uniform Plasma Etching
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Solution Overview
Problem
Existing plasma substrate treatment apparatuses face issues with non-uniform electric field generation, increased impedance, and reduced plasma uniformity due to the concentration of electric fields at the connection points of electrodes and power supply rods, leading to decreased substrate treatment efficiency.
Innovation Solution
The substrate support unit includes a dielectric plate, a lower electrode with a deformation portion, a power supply rod, and a ground member with a guide portion, which helps in minimizing electric field concentration, reducing impedance, and enhancing plasma uniformity by optimizing the RF power delivery and impedance control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power supply rod is directly connected to the lower electrode, then RF power can be supplied to generate plasma, but electric field concentration occurs at the connection point leading to non-uniform plasma distribution
Solution Approach 1:
The lower electrode is divided into a first lower electrode and a second lower electrode that are spaced apart from each other. The power supply rod connects to both electrodes rather than a single electrode, which segments the electric field distribution and prevents concentration at one location. This segmentation allows RF power to be supplied while maintaining uniform plasma generation across the substrate surface.
2Productivity
If high power is fed to the lower electrode, then plasma generation efficiency is improved, but impedance increases due to mutual electrical influences between the power supply rod and electrode
Solution Approach 1:
The first and second lower electrodes are positioned at different locations and connected to the power supply rod at different points. This creates localized electric fields at each electrode connection point rather than a single concentrated field. The local quality of the electric field distribution is optimized to reduce mutual electrical influences and impedance while maintaining high power delivery capability for efficient plasma generation.
3Reliability
If the power supply rod and lower electrode are in direct contact, then electrical connection is established, but electric field dispersion occurs leading to non-uniform RF current distribution
Solution Approach 1:
Instead of a single-point connection between the power supply rod and lower electrode, the connection is distributed across multiple points on the first and second lower electrodes. This transforms the connection from a zero-dimensional point contact to a multi-dimensional distributed connection, ensuring uniform RF current distribution across the electrode surfaces while maintaining reliable electrical connection.
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 improves etch rate uniformity across the substrate, minimizes eddy currents and noise during RF power feeding, and provides additional control over plasma density, thereby enhancing the overall substrate treatment efficiency.
Implementation Method 1
a power supply rod that applies RF power to the lower electrode
Implementation Method 2
Plasma is generated by heating a neutral gas to a very high temperature or subjecting the neutral gas to a strong electric field or a radio frequency (RF) electromagnetic field
Implementation Method 3
a lower electrode that is disposed under the dielectric plate... a power supply rod that applies RF power to the lower electrode
Implementation Method 4
A process of treating a substrate, such as a wafer, using plasma is performed by collision of ions and radicals contained in the plasma with the substrate
Data Source
AI summary
The inventive concept relates to a substrate support unit provided in an apparatus for treating a substrate using plasma. In an embodiment, the substrate support unit includes a dielectric plate on which the substrate is placed, a lower electrode that is disposed under the dielectric plate and that has a first diameter, a power supply rod that applies RF power to the lower electrode and has a second diameter, and a ground member disposed under the lower electrode and spaced apart from the lower electrode by a first gap by an insulating member, the ground member including a plate portion having a through-hole formed therein through which the power supply rod passes, in which the through-hole has a third diameter.