Auxiliary Electrode for Plasma Chamber Wall Potential Control
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Solution Overview
Problem
The challenge in plasma processing is controlling the potential difference between the processing chamber wall and plasma to prevent excessive erosion or deposition, which is exacerbated by the need to perform processes with different optimal high-frequency power levels in the same chamber, leading to instability and increased manufacturing costs.
Innovation Solution
A plasma processing apparatus with a potential-controlling high frequency power supply and a DC power supply, along with an auxiliary electrode, is used to independently control the wall potential by applying high frequency power or DC voltage, allowing for separate management of wall potential and plasma generation without affecting each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high frequency power is increased to improve etching rate and productivity, then productivity is improved, but wall erosion is increased
Solution Approach 1:
The patent divides the power control into two independent parts: plasma generation power (for etching) and wall potential control power (for erosion prevention). This segmentation allows each parameter to be optimized independently without compromising the other.
Solution Approach 2:
The patent introduces an auxiliary electrode as an intermediary component between the plasma chamber wall and the power supply system. This auxiliary electrode serves as a dedicated interface for applying wall potential control without directly affecting the plasma generation process.
2Productivity
If high frequency power is increased to meet throughput demand, then productivity is improved, but sputtering force on wall surface is increased causing more erosion
Solution Approach 1:
The patent changes the electrical parameter (wall potential) independently from the power parameter. By controlling wall potential through the auxiliary electrode, the system can compensate for the increased sputtering force caused by higher power, thereby protecting the wall while maintaining high throughput.
3Adaptability or versatility
If it is difficult to control wall potential under different process conditions, then adaptability is reduced, but device complexity increases with separate control systems
Solution Approach 1:
The auxiliary electrode serves multiple functions: it acts as a wall potential control interface, a plasma generation assistant, and a diagnostic probe. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting complexity increase while improving adaptability.
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 reduces excessive erosion and deposition on the chamber walls, maintaining a stable plasma state and improving productivity by allowing for precise control of the potential difference across varying process conditions.
Implementation Method 1
a plasma-exciting high frequency power supply for applying a plasma-exciting high frequency power
Implementation Method 2
a DC power supply for applying a DC voltage
Implementation Method 3
a high frequency bias power supply for applying a high frequency bias power... and ions are attracted to the lower electrode
Data Source
AI summary
A plasma processing apparatus for generating a plasma in a plasma processing space in a processing chamber and plasma-processing a target object includes a plasma-exciting high frequency power supply for applying a plasma-exciting high frequency power. Further, the plasma processing apparatus includes at least one of a potential-controlling high frequency power supply for applying a potential-controlling high frequency power having a frequency lower than that of the plasma-exciting high frequency power and a DC power supply for applying a DC voltage; and a mounting table for mounting thereon a target object. Furthermore, the plasma processing apparatus includes an auxiliary electrode, provided at a position outer side of the target object mounted on the mounting table while facing the mounting table, connected to at least one of the potential-controlling high frequency power supply and the DC power supply.