Plasma Chamber Electrode Potential Control via Capacitive Grounding
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Solution Overview
Problem
Existing plasma processing chambers face complexity and increased costs due to the need for potential control circuits to manage the electric potential of sidewalls and electrodes, which is not effective in uniformly removing polymer deposits, leading to potential damage and inefficiencies in plasma processing.
Innovation Solution
A structure comprising a grounded conductive member, an electrically floating conductive member, and an insulating member with a predetermined electric capacity, allowing for controlled potential adjustment without a potential control circuit, simplifying the chamber construction and enhancing plasma processing efficiency by managing the potential and reactance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a potential control circuit with impedance adjusting means is disposed between the sidewall and ground potential to control the potential of the sidewall, then the potential of the sidewall can be controlled to adjust the number of times of collision of positive ions against the sidewall, but the construction of the plasma processing chamber becomes complicated and manufacturing costs increase
Solution Approach 1:
The invention extracts the potential control function from a complex impedance adjusting circuit and implements it through a simple capacitor connected between the sidewall and ground. This capacitor-based approach removes the need for variable capacitors, coils, and control circuits, achieving potential control through a passive, simple component that only adds minimal structural complexity.
Solution Approach 2:
The invention uses a simple, fixed-value capacitor instead of expensive, complex impedance adjusting means. The capacitor is a basic electronic component that is inexpensive and requires no active control, thereby reducing both construction complexity and manufacturing costs while maintaining the essential potential control function.
2Reliability
If the anode/cathode ratio of the container is adjusted by changing the gap between electrodes or position of exhaust plate to control sidewall potential, then the potential can be controlled, but the distribution of plasma density and other parameters cannot be set preferably for etching
Solution Approach 1:
The invention segments the potential control function from the plasma generation and density control functions. By adding a dedicated capacitor for potential control, the electrode gap and exhaust plate positions can be independently optimized for plasma density distribution without compromising sidewall potential control, thereby resolving the conflict between these two control objectives.
Solution Approach 2:
The capacitor acts as an intermediary component that provides potential control without interfering with the plasma generation process. It mediates between the sidewall and ground, allowing potential adjustment while leaving the electrode configuration and exhaust plate position free to be optimized for optimal plasma density distribution.
3Reliability
If a potential control circuit is disposed between electrodes and ground potential to control electrode potential, then electrode potential can be controlled to prevent electrode shaving, but the construction becomes complicated and costs increase
Solution Approach 1:
The invention extracts the electrode potential control function from complex impedance adjusting circuits and implements it through simple capacitors connected between each electrode and ground. This approach removes the need for variable capacitors, coils, and active control circuits, achieving potential control through passive, simple components.
Solution Approach 2:
The invention uses simple, fixed-value capacitors instead of expensive, complex potential control circuits. These basic electronic components are inexpensive and require no active control, thereby reducing both construction complexity and manufacturing costs while preventing electrode shaving.
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 enables effective control of potential and reactance, ensuring uniform polymer removal and preventing electrode damage, thereby simplifying the plasma processing chamber construction and improving processing efficiency.
Implementation Method 1
a structure comprising a grounded conductive member, an electrically floating conductive member, and an insulating member with a predetermined electric capacity
Data Source
AI summary
A structure for a plasma processing chamber which makes it possible to control the potential therein and simplify the construction of the plasma processing chamber. A gas-introducing showerhead 34 is disposed in the plasma processing chamber 10 including a container 11 having a process space S for receiving a semiconductor wafer W, and a susceptor 12 disposed in the container 11, for mounting the received semiconductor wafer W thereon. The susceptor 12 is connected to high-frequency power supplies 20 and 46. An electrode support 39 of the gas-introducing showerhead 34 is electrically grounded. An electrically floating top electrode plate 38 of the gas-introducing showerhead 34 is disposed between the electrode support 39 and the process space S. The top electrode plate 38 has a surface exposed to the process space S. An insulating film 48 is formed of a dielectric material and disposed between the electrode support 39 and the top electrode plate 38.