Bias Electrode Circuit Layout for Plasma Ringing Suppression
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Solution Overview
Problem
Existing plasma processing apparatuses face issues with ringing superimposition on pulsed DC signals, leading to inefficient energy transmission and unstable ion energy distribution during plasma processing.
Innovation Solution
Incorporation of a ringing suppression circuit with ferrite cores to suppress ringing on pulsed DC signals, utilizing a sequence of voltage pulses with specific polarity and frequency ranges, and parallel conductors to manage parasitic capacitances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pulsed DC signal is applied to the bias electrode without ringing suppression, then the plasma processing can be performed with simple circuit configuration, but ringing superimposition occurs causing unstable ion energy distribution and inefficient energy transmission
Solution Approach 1:
The patent introduces an RF filter as an intermediary component between the pulsed DC generator and the bias electrode. This RF filter acts as a mediator that removes ringing superimposition from the pulsed DC signal without requiring complex circuit reconfiguration, thereby stabilizing ion energy distribution while maintaining relatively simple overall circuit architecture
Solution Approach 2:
The patent applies parameter changes by introducing specific circuit parameters (RF filter characteristics, pulse width, pulse frequency) to control and suppress ringing effects. By optimizing these parameters, the system achieves stable ion energy distribution and efficient energy transmission without fundamentally changing the circuit topology
2Productivity
If ringing suppression circuit is added to suppress ringing on pulsed DC signal, then energy transmission efficiency and ion energy stability are improved, but device complexity increases
Solution Approach 1:
The RF filter serves as an intermediary component that efficiently suppresses ringing with minimal impact on overall system complexity. It is inserted in series between the pulsed DC generator and bias electrode, providing effective ringing suppression while adding only one discrete component to the circuit
3Productivity
If high power RF signal is used for plasma generation, then plasma processing speed and etching rate are improved, but parasitic capacitance effects and ringing become more severe
Solution Approach 1:
The patent converts the harmful effect of parasitic capacitance into a beneficial one by designing the RF filter to resonate at a specific frequency. The parasitic capacitance, which normally causes ringing, is instead utilized as part of the resonant circuit that actively suppresses ringing superimposition on the pulsed DC signal, thereby enabling high power operation without exacerbating ringing effects
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
Enhances efficient energy transmission to the substrate, stabilizes ion energy distribution, and improves etching rates by reducing ringing effects.
Implementation Method 1
a ringing suppression circuit that is connected between the bias electrode and the pulsed DC generator and that is configured to suppress ringing superimposed on the pulsed DC signal
Implementation Method 2
an electrostatic chuck disposed on the conductive base
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber; a substrate support including a conductive base, an electrostatic chuck disposed on the conductive base, a chuck electrode disposed in the electrostatic chuck, and a bias electrode disposed below the chuck electrode; an upper electrode that is disposed above the substrate support; an RF generator that is electrically connected to the conductive base, the bias electrode, or the upper electrode and that is configured such that an RF signal is generated; a pulsed DC generator that is electrically connected to the bias electrode and that is configured to generate a pulsed DC signal; an RF filter that is connected between the bias electrode and the pulsed DC generator; and a ringing suppression circuit that is connected between the bias electrode and the pulsed DC generator and that is configured to suppress ringing superimposed on the pulsed DC signal.