Dual-Coil Plasma Antenna Shielding for Uniform Density Control
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Solution Overview
Problem
In plasma processing apparatuses, abnormal discharge can occur in the gas line due to high-frequency power radiation from the inner antenna, leading to damage and particle scattering on the substrate, which complicates uniform plasma density control across the substrate surface.
Innovation Solution
A plasma processing apparatus design featuring an inner coil and an outer coil with specific configurations to resonate at different frequencies, where the inner coil is connected through a capacitor and inductively coupled with the outer coil, and a conductive shielding member is used to prevent abnormal discharge by controlling the electromagnetic wave energy entering the gas injection unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the inner antenna is disposed near the gas supply line to control plasma density distribution, then plasma density control is improved, but abnormal discharge occurs in the gas line causing damage and particle scattering
Solution Approach 1:
A conductive shielding member is introduced as an intermediary between the inner antenna and the gas supply line. This shielding member blocks the electromagnetic field from directly interacting with the gas line, preventing abnormal discharge while allowing the inner antenna to maintain its position for plasma density control. The shielding member acts as a mediator that protects the gas line from harmful electromagnetic effects.
Solution Approach 2:
The patent converts the potentially harmful electromagnetic radiation from the inner antenna into a beneficial configuration by using the conductive shielding member to redirect and contain the electromagnetic field. The shielding member transforms what would be harmful radiation into a controlled field distribution that improves plasma uniformity without damaging the gas line.
2Productivity
If the inner antenna resonates at a frequency with wavelength half of the high frequency power to control plasma, then plasma generation is improved, but the antenna structure becomes complex requiring precise frequency matching
Solution Approach 1:
The patent applies parameter changes by adjusting the resonance frequency and wavelength of the inner antenna to be half of the high frequency power supplied. This specific parameter relationship optimizes plasma generation efficiency while the conductive shielding member simplifies the overall system by eliminating the need for complex frequency coordination between multiple antennas.
3Manufacturing precision
If high frequency power is supplied to the inner antenna to generate plasma, then plasma density control is improved, but the high frequency power radiated damages the gas line through abnormal discharge
Solution Approach 1:
The conductive shielding member serves as a protective intermediary that allows high frequency power to be supplied to the inner antenna for precise plasma density control while preventing the radiated electromagnetic energy from damaging the gas line. The shielding member maintains system reliability by blocking harmful radiation paths.
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 allows for precise control of plasma density distribution and suppresses abnormal discharge, ensuring efficient processing and uniformity across the substrate surface while preventing damage to the gas line.
Implementation Method 1
an antenna provided above the chamber to surround the gas supply unit and configured to generate plasma of the processing gas in the chamber by supplying a high frequency power into the chamber
Implementation Method 2
the one coil resonates at a wavelength that is a half of a wavelength of the high frequency power supplied from the power supply unit
Implementation Method 3
the other coil is inductively coupled with the one coil
Implementation Method 4
a conductive shielding member is used to prevent abnormal discharge by controlling the electromagnetic wave energy entering the gas injection unit
Data Source
AI summary
A plasma processing apparatus includes an antenna configured to generate plasma of a processing gas in a chamber. The antenna includes: an inner coil provided around the gas supply unit to surround a gas supply unit; and an outer coil provided around the gas supply unit and the inner coil to surround them. The outer coil is configured such that both ends of a wire forming the outer coil are opened; power is supplied from a power supply unit to a central point of the wire; the vicinity of the central point of the wire is grounded; and the outer coil resonates at a wavelength that is a half of a wavelength of the high frequency power. The inner coil is configured such that both ends of a wire forming the inner coil are connected through a capacitor and the inner coil is inductively coupled with the inner coil.