Plasma Electrode Circuit for Lower Ion Energy at the Substrate
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Solution Overview
Problem
Existing plasma processing technologies face challenges in reducing the energy of ions incident on a substrate, leading to potential damage during plasma processing.
Innovation Solution
A plasma processing apparatus with a circuit portion that connects between a high-frequency power supply and a lower electrode, allowing current to flow from the power supply to the electrode when its potential is higher, thereby equalizing or exceeding the electrode's potential, reducing sheath voltage and ion energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the lower electrode potential is kept low during plasma processing, then plasma generation efficiency is improved, but ion energy incident on the substrate increases causing damage
Solution Approach 1:
The patent segments the electrical connection path by introducing a circuit portion with switching element between the high-frequency power supply and the lower electrode. This allows independent control of plasma generation power and electrode potential, enabling the lower electrode to be segmented into a plasma generation region (connected to power supply) and a substrate support region (with controlled potential)
Solution Approach 2:
The patent changes the electrical parameter (potential) of the lower electrode dynamically by controlling the switching element. The circuit portion adjusts the lower electrode potential to be equal to or higher than the high-frequency power supply potential during certain phases, thereby reducing ion energy incident on the substrate while maintaining plasma generation efficiency
2Object-affected harmful factors
If a circuit portion is added to control lower electrode potential, then ion energy is reduced and substrate damage is prevented, but device complexity increases
Solution Approach 1:
The patent introduces a circuit portion as an intermediary component between the high-frequency power supply and the lower electrode. This intermediary contains a switching element that mediates the electrical connection, allowing controlled potential adjustment to reduce ion energy without requiring complete system redesign
Solution Approach 2:
The circuit portion is designed to perform multiple functions: it controls the lower electrode potential, manages power flow from the high-frequency power supply, and prevents excessive ion energy incident on the substrate. This multi-functionality reduces the need for separate dedicated components for each function
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 reduces ion energy at the substrate boundary, preventing increased sheath voltage when power flows to ground, thus minimizing substrate damage during plasma processing.
Implementation Method 1
a high-frequency power supply electrically connected to the upper electrode and configured to generate a plasma of the processing gas by applying a high-frequency voltage to the upper electrode
Data Source
AI summary
A plasma processing apparatus comprising: a chamber; a lower electrode provided in the chamber and included in a substrate support mounts a substrate thereon; an upper electrode provided in the chamber and disposed to face the lower electrode; a gas supply configured to supply a processing gas between the upper electrode and the lower electrode; a high-frequency power supply electrically connected to the upper electrode and configured to generate a plasma of the processing gas by applying a high-frequency voltage to the upper electrode; and a circuit portion electrically connected between the high-frequency power supply and the lower electrode and provides a potential to the lower electrode. The circuit portion provides the potential to the lower electrode by causing a current to flow from the high-frequency power supply toward the lower electrode when a potential of the high-frequency power supply is higher than a potential of the lower electrode.